14.2: Mesoamerica
Cultures of Mesoamerica
Mesoamerica was dominated by three cultures in the Pre-Classical (up to 200 CE) to Post-Classical periods (circa 1580 CE): the Olmec, Maya, and Aztec.
Identify distinctive trends and materials in each of these civilization’s art production
Key Points
- The Olmec people are known for extraordinarily detailed jade figurines and colossal heads of rulers made of basalt.
- Mayan culture achieved an advanced system of hieroglyphic writing, a sophisticated calendar, and a productive system of art patronage .
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The Mayan civilization rose very quickly. Although much of its art was lost to the Spanish Conquest in the 16th century, many stone and wood sculptures
that attest to the Mayan’s distinctive religious beliefs still survive.
Key Terms
- stelae : Upright stone slabs or columns typically bearing a commemorative inscription or relief design, often serving as gravestones. (singular: stela)
- jade : An ornamental rock with green and blue properties.
- Mesoamerica : A pre-Columbian cultural region extending from the southern part of Mexico to an area that comprises some parts of the countries of Central America.
- hieroglyphic : A type of writing consisting of hieroglyphs, a largely pictorial character of the Ancient Egyptian writing system.
Mesoamerica is a region in the Americas that extends from central Mexico to northern Costa Rica. Three cultures dominated the pre-Columbian history of Mesoamerica: the Olmec, Maya, and Aztec civilizations.
Olmec Culture
The Olmec civilization, which flourished from 1200–400 BCE, defines the Pre- Classical period; the Olmecs are generally considered the forerunner of all Mesoamerica cultures including the Maya and Aztecs. Primarily centered in the modern states of Tabasco and Veracruz in the Gulf of Mexico, the Olmec people are known for creating an abundance of small and extraordinarily detailed jade figurines. The figurines typically exhibit complex shapes such as human figures, human-animal composites of deities and gods, and animals like cats and birds. Although we don’t know the specific purpose of these jade objects, their presence in some Olmec graves suggests they served a religious purpose in addition to being signs of wealth and goods for trade.
The Olmec are also known for building massive stone sculptures, many of which were discovered at La Venta in the modern Mexican state of Tabasco. Made from basalt rock from the Tuxtla mountains to the north, the Olmec used this rock to create altars, stelae , and colossal heads. Each head is rendered as a distinct individual and is thought to resemble an Olmec ruler. Each ruler’s personality is represented in the distinct headdresses that adorn the sculptures’ heads.
Mayan Culture
Mayan culture peaked during the Classical period (ca. 200–900 CE) and featured complex organization of large agricultural communities ruled by monarchs. They built imposing pyramids , temples, palaces, and administrative structures in densely populated cities in southern Mesoamerica. The Maya had the most advanced hieroglyphic writing in Mesoamerica and the most sophisticated calendrical system. In Mayan culture, we also see one of the earliest systems of art patronage. Kings and queens employed full-time artists in their courts, many of whom signed their work. It’s thus unsurprising that the most common motifs in Mayan art are mortal rulers and supernatural beings.
In Palenque, Mexico (a prominent Mayan city in the Classical period), the ruler Lord Pakal commissioned a grouping of large structures that stand on high ground in the middle of the town. One of those buildings, the Temple of the Inscriptions, is a nine-level pyramid that is 75 feet high. The layers of the structure probably reflect the Mayan belief that the underworld had nine levels. Inscriptions line the back wall of the temple, giving the building its name.
Aztec Culture
Mayan civilization was in decline by the time of the Spanish Conquest in the early 16th century, and by then the Aztecs controlled much of Mexico. The rise of the Aztec was quick. Once a migratory people, they arrived in the Basin of Mexico in the 13th century where they eventually settled on an island in Lake Texcoco; they called their new home Tenochtitlan. In only a few centuries, the Aztecs aggressively expanded their territory and transformed Tenochtitlan into a capital so grand that the Spanish conquistador Hernan Cortes remarked on its beauty en route to invade the city in November 1519.
Metalwork was a particular skill of the Aztecs. Unfortunately, very few examples of their characteristic small gold and silver objects survive. When the Spanish arrived, most were melted down for currency. Stone sculpture and wood figurines fared much better during the Conquest. Aztec sculpture, most of which took the form of human figures carved from stone and wood, were not religious idols as one might suspect. Instead of containing the spirit of a deity, monumental sculptures were made to “feed” the deities with blood and precious objects in order to keep the gods, who resided elsewhere in the temples, happy. These sculptures are the source of stories told by Spanish conquistadors of huge statues splattered with blood and encrusted with jewels and gold.
Colossal Heads of the Olmec
The Olmec culture of the Gulf Coast of Mexico produced the first major Mesoamerican art and is particularly known for the creation of colossal stone heads.
Describe the colossal stone heads made by the Olmecs
Key Points
- The Olmec built large cities with ceremonial centers. They also made small sculptures and figurines from many types of material. Using huge basalt boulders transported from mountains in another region, the Olmec produced at least 17 sculptures of human heads.
- The monuments are thought to represent Olmec rulers because of their distinct facial features and adornments.
- The heads date from between 1500 and 400 BCE.
- The only example of a colossal head found in a region outside the Olmec’s domain is at Takalik Abaj in Guatemala.
Key Terms
- Olmec : Ancient pre-Columbian people living in the tropical lowlands of south-central Mexico, in roughly the modern-day states of Veracruz and Tabasco.
- earspools : Cylindrical earrings that pierce the earlobe.
- Preclassic period : Also known as the Formative period, dating roughly from as early as 1500 BCE to about 400 BCE.
The First Major Mesoamerican Art
The art of the Olmec, which emerged during the preclassic period along the Gulf of Mexico, was the first major Mesoamerican art. Across the swampy coastal areas of the modern Mexican states of Veracruz and Tabasco, the Olmec constructed ceremonial centers on raised earth mounds. These centers were filled with objects made from materials including jade , clay, basalt, and greenstone. Most of these objects were figurines or sculptures that resembled both human and animal subjects.
While Olmec figurines are found abundantly in sites throughout the Formative period, monumental works of basalt sculpture, including colossal heads, altars, and seated figures are the most recognizable feature of this culture . The huge basalt rocks for the large sculptures were quarried at distant sites and transported to Olmec centers such as San Lorenzo and La Venta. The colossal heads range in height from 5 to 12 feet and portray adult males wearing close-fitting caps with chin straps and large, round earspools . The fleshy faces have almond-shaped eyes, flat, broad noses, thick, protruding lips, and downturned mouths. Each face has a distinct personality, suggesting that they represent specific individuals.
These massive basalt boulders were transported from the Sierra de los Tuxtlas Mountains of Veracruz. When originally displayed in Olmec centers, the heads were arranged in lines or groups; however, the method used to transport the stone to these sites remains unclear. Given the enormous weight of the stones and the manpower required to transport them over large distances, it is probable that the colossal portraits represent powerful Olmec rulers.
The discovery of a colossal head at Tres Zapotes in the nineteenth century spurred the first archaeological investigations of Olmec culture by Matthew Stirling in 1938. Seventeen confirmed examples are traced to four sites within the Olmec heartland on the Gulf Coast of Mexico. Most colossal heads were sculpted from spherical boulders, but two from San Lorenzo Tenochtitlán were recarved from massive stone thrones. An additional monument at Takalik Abaj in Guatemala is a throne that may have been carved from a colossal head. This is the only known example from outside the Olmec heartland.
Dating the monuments remains difficult because of the movement of many from their original contexts prior to archaeological investigation. Most have been dated to the Early Preclassic (or Formative) period (1500–1000 BCE) with some to the Middle Preclassic (1000–400 BCE) period. The smallest weighs six tons, while the largest is estimated to weigh 40 to 50 tons, although it was abandoned and left unfinished close to the source of its stone.
Teotihuacan
At its height, Teotihuacan was one of the largest cities in the world with a population of 200,000. It was a primary center of commerce and manufacturing.
Understand the importance of Teotihuacan as a religious, commercial, and art historical center
Key Points
- The name Teotihuacan means Gathering Place of the Gods.
Key Terms
- taludtablero : A design characteristic of Mayan architecture at Teotihuacan in which a sloping talud at the base of a building supports a wall-like tablero, where ornamental painting and sculpture are usually placed.
Located some 30 miles northeast of present-day Mexico City, Teotihuacan experienced a period of rapid growth early in the first millennium CE. By 200 CE, it emerged as a significant center of commerce and manufacturing, the first large city-state in the Americas. At its height between 350 and 650 CE, Teotihuacan covered nearly nine miles and had a population of about 200,000, making it one of the largest cities in the world. One reason for its dominance was its control of the market for high-quality obsidian. This volcanic stone, made into tools and vessels , was traded for luxury items such as the green feathers of the quetzal bird, used for priestly headdresses, and the spotted fur of the jaguar, used for ceremonial garments.
The people of Teotihuacan worshipped deities that were recognizably similar to those worshipped by later Mesoamerican people, including the Aztecs, who dominated central Mexico at the time of the Spanish Conquest. Among these are the Rain or Storm God (god of fertility, war, and sacrifice), known to the Aztecs as Tlaloc, and the Feathered Serpent, known to the Maya as Kukulcan and to the Aztecs as Quetzalcoatl.
Teotihuacan’s principal monuments include the Pyramid of the Sun, the Pyramid of the Moon, and the Ciudadela (Spanish for fortified city center), a vast sunken plaza surrounded by temple platforms. The city’s principal religious and political center, the Ciudadela could accommodate an assembly of more than 60,000 people. Its focal point was the pyramidal Temple of the Feathered Serpent. This seven-tiered structure exhibits the taludtablero construction that is a hallmark of the Teotihuacan architectural style . The sloping base, or talud , of each platform supports a vertical tablero , or entablature , which is surrounded by frame and filled with sculptural decoration . The Temple of the Feathered Serpent was enlarged several times, and as was characteristic of Mesoamerican pyramids, each enlargement completely enclosed the previous structure like the layers of an onion. Archaeological excavation of this temple’s earlier-phase tableros and a stairway balustrade have revealed painted heads of the Feathered Serpent, the goggle-eyed Rain or Storm God, and reliefs of aquatic shells and snails. The flat, angular, abstract style, typical of Teotihuacan art, is in marked contrast to the curvilinear style of Olmec art.
The Decline
Sometime in the middle of the seventh century disaster struck Teotihuacan. The ceremonial center burned and the city went into a permanent decline. Nevertheless, its influence continued as other centers throughout Mesoamerica and as far south as the highlands of Guatemala borrowed and transformed its imagery over the next several centuries. The site was never entirely abandoned as it remained a legendary pilgrimage center. The much later Aztec people (c. 1300-1525 CE) revered the site as the place where they believed the gods created the sun and the moon. In fact, the name “Teotihuacan” is actually an Aztec word meaning “Gathering Place of the Gods.”
Art of the Maya
Mayan art includes a wide variety of objects, commissioned by rulers, that depict scenes of both elite and everyday society.
Identify the key features of Mayan art from the Classic Period
Key Points
- Maya blue was a distinctive color preserved for centuries due to its unique chemical composition; unfortunately, the technique involved in producing it has been lost.
- The Maya carved stone portraits of their rulers as memorials.
- There is an especially strong tradition of painting and sculpture in Mayan culture . Often sculpture was painted with distinctive dyes and techniques characteristic of the Maya.
- Much Mayan art was commissioned by rulers to accompany them to the Underworld.
Key Terms
- Stele : As stone slab placed vertically and decorated with inscriptions or reliefs. Used as a grave marker or memorial.
- Maya blue : A unique bright azure pigment manufactured by cultures of pre-Columbian Mesoamerica, such as the Maya and Aztec. Made from a combination of a particular kind of clay, indigo, and vegetable dye.
Mayan Portraiture
Strong cultural influences stemming from the Olmec tradition and Teotihuacan contributed to the development of the Mayan city center and the culture’s Classic artistic tradition. The most sacred and majestic buildings of Mayan cities were built in enclosed, centrally located precincts. The Maya held dramatic rituals within these highly sculptured and painted environments. For example, the grand pyramids of Copan and Tikal are among the most imposing buildings the Maya erected; each contains sculpted portraits that glorified the city’s rulers.
Stele H in the Great Plaza at Copan represents one of the city’s foremost leaders, 18-Rabbit, who reigned from 695-738 CE. During the ruler’s long reign, Copan reached its greatest physical extent and breadth of political influence. On Stele H, 18-Rabbit wears an elaborate headdress and ornamented kilt and sandals. He holds across his chest a double-headed serpent bar, symbol of the sky and of his absolute power. His features, although idealized, have the quality of a portrait likeness. The Mayan elite, like the Egyptian pharaohs, tended to have themselves portrayed as eternally youthful. The dense, deeply carved ornamental details that frame the face and figure stand almost clear of the main stone block and wrap around the sides of the stele. The stele was originally painted, with remnants of red paint visible on many stelae and buildings in Copan.
Clay Sculpture
Many small clay figures from the Classic Mayan period remain in existence.  As a group, they are remarkably life-like, carefully descriptive, and even comic at times. They represent a wider range of human types and activities than commonly depicted on Mayan stelae. Ball players, women weaving, older men, dwarves, supernatural beings, and amorous couples, as well as elaborately attired rulers and warriors, comprise one of the largest groups of surviving Mayan art. Many of the hollow figurines are also whistles. They were made in ceramic workshops and painted with Maya Blue, a dye unique to Mayan and Aztec artists. Small clay figures found in burial sites were made to accompany the Mayan dead on their inevitable voyage to the Underworld.
Painted Vases
The Maya painted vivid narrative scenes on the surfaces of cylindrical vases. A typical vase design depicts a palace scene where an enthroned Mayan ruler sits surrounded by courtiers and attendants. The figures wear simple loincloths, turbans of wrapped cloth and feathers, and black body paint. These painted vases may have been used as drinking and food vessels for noble Maya, but their final destination was the tomb, where they accompanied the deceased to the Underworld. They likely were commissioned by the deceased before his death or by his survivors, and were occasionally sent from distant sites as funerary offerings .
Architecture of the Maya
The Maya had complex architectural programs. They built imposing pyramids, temples, palaces, and administrative structures in densely populated cities.
Describe the characteristic style and functional elements of Maya architecture in the Classic and Postclassic periods
Key Points
- The Maya grouped large architectural structures at the centers of major cities.
- Pyramids and temples were used for religious purposes and built by rulers as memorials to themselves.
- Administrative structures such as the Palace demonstrate the sophistication of Maya architecture and technology.
- Maya architecture is ornate and elaborate, incorporating bas- relief , sculpture , and painted murals on the interiors and exteriors of structures.
- The Mesoamerican ball game was a central part of ancient Mesoamerican cultural, religious, and political life.
- The cities of Palenque and Chichen Itza, both in Mexico, contain iconic examples of Mayan architecture from the Classical and Postclassical periods.
Key Terms
- roof comb : In a Mayan building, a masonry wall along the apex of a roof built above the level of the roof proper. Roof combs support the highly decorated false facades that rise above the height of the building at the front.
- mansard roof : A roof with four sloping sides that become steeper halfway down.
- aqueduct : An artificial channel for conveying water, typically in the form of a bridge supported by tall columns across a valley.
- bas-relief : A kind of sculpture in which shapes are carved so that they are only slightly higher than the flat background.
- balustrades : A kind of low wall placed at the sides of staircases, bridges, etc., made of a row of short posts topped by a long rail.
The Mayan civilization emerged during the late Preclassic period (250 BCE-250 CE), reached its peak in the southern lowlands of Guatemala during the Classic period (250-900 CE), and shifted to northern Yucatan during the Postclassic period (900-1521 CE).
Architecture in Palenque
In Palenque, Mexico, a prominent city of the Classic period, the major buildings are grouped on high ground . The central group of structures includes the Palace (possibly an administrative and ceremonial center as well as a residential structure), the Temple of the Inscriptions, and two other temples. Most of the structures in the complex were commissioned by a powerful ruler, Lord Pakal, who reigned from 615 to 638 CE, and his two sons, who succeeded him.
Temple of the Inscriptions
The Temple of the Inscriptions is a nine-level pyramid that rises to a height of about 75 feet. The consecutive layers probably reflect the belief, current among the Aztec and Maya at the time of the Spanish conquest, that the underworld had nine levels. Priests would climb the steep stone staircase on the exterior to reach the temple on top, which recalls the kind of pole-and-thatch houses the Maya still build in parts of the Yucatan today. The roof of the temple was topped with a crest known as a roof comb , and its facade still retains much of its stucco sculpture. Inscriptions line the back wall of the outer chamber, giving the temple its name.
The Palace
Across from the Temple of Inscriptions is the Palace , a complex of several adjacent buildings and courtyards built on a wide artificial terrace. The Palace was used by the Mayan aristocracy for bureaucratic functions, entertainment, and ritual ceremonies .
Numerous sculptures and bas-relief carvings within the Palace have been conserved. The Palace’s most unusual and recognizable feature is the four-story tower known as the Observation Tower. Like many other buildings at the site, the Observation Tower exhibits a mansard roof . The Palace was equipped with numerous large baths and saunas which were supplied with fresh water by an intricate water system. An aqueduct constructed of great stone blocks with a six-foot-high vault diverts the Otulum River to flow underneath the main plaza.
Architecture in Chichen Itza
As the focus of Maya civilization shifted northward in the Postclassic period, a northern Maya group called the Itza rose to prominence. Their principal center, Chichen Itza, (Yucatan State) Mexico, which means “at the mouth of the well of the Itza,” flourished from the 9th to 13th centuries CE, eventually covering about six square miles.
El Castillo
One of Chichen Itza’s most conspicuous structures is El Castillo (Spanish for the castle), a massive nine-level pyramid in the center of a large plaza with a stairway on each side leading to a square temple on the pyramid’s summit. At the spring and fall equinoxes, the setting sun casts an undulating, serpent-like shadow on the stairways, forming bodies for the serpent heads carved at the base of the balustrades .
The Great Ball Court
The Great Ball Court northwest of the Castillo is the largest and best preserved court for playing the Mesoamerican ball game, an important sport with ritual associations played by Mesoamericans since 1400 BCE. The parallel platforms flanking the main playing area are each 312 feet long. The walls of these platforms stand 26 feet high. Rings carved with intertwined feathered serpents are set high at the top of each wall at the center. At the base of the interior walls are slanted benches with sculpted panels of teams of ball players. In one panel, one of the players has been decapitated; the wound spews streams of blood in the form of wriggling snakes.
At one end of the Great Ball Court is the North Temple, also known as the Temple of the Bearded Man (Templo del Hombre Barbado). This small masonry building has detailed bas-relief carving on the inner walls, including a center figure with decorative carvings that resemble facial hair. Built into the east wall are the Temples of the Jaguar. The Upper Temple of the Jaguar overlooks the ball court and has an entrance guarded by two large columns carved in the familiar feathered serpent motif . At the entrance to the Lower Temple of the Jaguar is another Jaguar throne similar to the one in the inner temple of El Castillo.
Ceramics of the Veracruz
Ceramic figurines are a hallmark of Classic Veracruz art. The Veracruz people produced a variety of small clay figures in multiple areas around the modern state of Veracruz, Mexico.
Describe characteristics of ceramic figurines from two parts of Veracruz known for ceramic production in the Classic and Late Classic periods
Key Points
- The Classic Veracruz culture produced ceramic figurines in multiple distinctive styles and depicting many types of people.
- There are strong stylistic differences between ceramic figures from the cities of Remojadas and Nopiloa.
- The highly ritualized Mesoamerican ball game was of crucial importance to the Veracruz culture and was represented in their art.
- Smiling figures from Remojadas called Sonrientes are the most recognizable ceramic figures produced by the Veracruz people.
Key Terms
- Mesoamerican ballgame : A sport with ritual associations played since 1,400 BC by the pre-Columbian peoples of Ancient Mesoamerica. The sport had different versions in different places during the millennia, and a more modern version of the game, ulama, is still played in a few places by the indigenous population.
- Sonrientes : A type of ceramic figurine produced by the Veracruz culture. Literally translates to “smiling” in Spanish.
- appliqués : In the context of ceramics, adding low-relief clay forms to hard surfaces for embellishment.
The modern state of Veracruz lies along the Mexican Gulf Coast, north of the Maya lowlands and east of the highlands of central Mexico. Culturally diverse and environmentally rich, the people of Veracruz took part in dynamic interchanges between three regions that over the centuries included trade, warfare, and migration. During the middle centuries of the first millennium, the artistically gifted Veracruzanos created inventive ceramic sculpture in diverse yet related styles.
Until the early 1950s, Classic Veracruz ceramics were few, little understood, and generally without provenance (known history). Since then, the recovery of thousands of figurines and pottery pieces from sites such as Remojadas and Nopiloa (some initially found by looters), has expanded our understanding and filled many museum shelves. Artist and art historian Miguel Covarrubias described Classic Veracruz ceramics as “powerful and expressive, endowed with a charm and sensibility unprecedented in other, more formal cultures.”
Figurines from Remojadas and Nopiloa
Remojadas-style figurines, perhaps the most easily recognizable from this culture, are usually hand-modeled and often adorned with appliqués . Of particular note are the Sonrientes (Smiling) Figurines, with triangular-shaped heads and outstretched arms. Figurines from Nopiloa are often molded and usually less ornate, without appliqués. The Sonrientes figure from Remojadas (below) provides scholars with an example of the clothing worn in ancient times, such as the loincloth and headdress. The flattened forehead on this smiling figure may represent the practice of intentional cranial deformation or may simply reflect an artistic convention. Many American cultures considered a flattened forehead desirable and used a variety of techniques to flatten the skulls of infants while they were still pliable.
Another smiling figure from the Remojadas region is a hollow ceramic sculpture representing an individual celebrating with music and dance. This bare-chested figure with open mouth and filed teeth stands energetically with legs spread and arms lifted as if caught in mid-motion. He wears a woven cap with geometric patterns, an elaborate skirt, circular earrings, a beaded necklace, and a bracelet. His face and body contain patterns evocative of body paint, including slight lines emanating from his lower eyelids and onto his cheeks. This sculpture evokes a festive dance or ritual accompanied by the rhythmic reverberation of the hand-held rattle and celebratory sound escaping from the figure’s open mouth.
In contrast to Smiling Figures from Remojadas, the mold-made ceramic figure from Nopiloa below depicts a bearded, mustachioed male wearing a ballgame yoke around his waist to protect him from the hard, solid rubber ball used in play. There are cylindrical ear ornaments in his ears and beneath his arm, a baton-like object perhaps related to the local incarnation of the game. The rules and manner in which the Mesoamerican ballgame was played varied among contemporary sites and evolved through time. Surviving evidence suggests human sacrifice was a frequent outcome, but the game may also have been played for other purposes such as sport. The people of ancient Veracruz interacted with people from other Mesoamerican cultures, and this Nopiloa figure displays motifs commonly found in Mayan art. Knotted ties like those around this player’s wrist and neck connote captured prisoners in Mayan pictorial language. A motif similar to the Maya mat, a symbol of rulership, appears on the flanged headdress of the ballplayer. Like Mayan figurines of this type, the body of this figure is a whistle, a musical instrument used in ritual and ceremony .
Codices of the Mixtec
Mixtec culture had a unique and complex writing system that used characters and pictures to represent complete words and ideas instead of syllables or sounds. They made codices to document important historical events in their society.
Understand the uses and structure of Mixtec codices
Key Points
- Mixtec codices were made of deerskin and folded in an accordion pattern. Only eight Mixtec codices survive.
- Mixtec codices allow us to trace Mixtec history from 1550 CE back to 940 CE, deeper in time than any other Mesoamerican culture except the Maya.
- Codices represented historical events on both a micro and macro scale for Mixtec nobility.
Key Terms
- codices : Books constructed of sheets of paper, vellum, papyrus, or similar materials, with hand-written contents. Codex: singular
- logographic : Type of written language in which the characters/pictures used represent complete words and ideas instead of syllables or sounds.
- Mixtec : A Mesoamerican people who lived in southern Mexico before the rise of the Aztecs.
About the Mixtec
The Mixtecs were one of the most influential ethnic groups to emerge in Mesoamerica during the Post-Classic period. Never a united nation, the Mixtecs waged war and forged alliances among themselves as well as with other peoples in their vicinity. They also produced beautiful manuscripts and metal work and influenced the international artistic style used from Central Mexico to Yucatan.
During the Classic period, the Mixtecs lived in hilltop settlements of northwestern Oaxaca, a fact reflected in their name in their own language, Ñuudzahui, meaning “People of the Rain.” During the Post-Classic period, the Mixtecs slowly moved into adjacent valleys and then into the great Valley of Oaxaca. This time of expansion is recorded in a large number of deerskin manuscripts called codices , only eight of which have survived. Nevertheless, these manuscripts allow us to trace Mixtec history from 1550 CE back to 940 CE, deeper in time than any other Mesoamerican culture except the Maya.
Mixtec Codices
Mixtec codices represent a type of writing classified as logographic , meaning the characters and pictures used represent complete words and ideas instead of syllables or sounds. In Mixtec, the relationships among pictorial elements denote the meaning of the text, whereas in other Mesoamerican writing the pictorial representations are not incorporated into the text. Common topics found in the codices are biographies of rulers and other influential figures, records of elite family trees, mythologies, and accounts of ceremonies .
The above detail from the Codex Zouche-Nuttall depicts a group of warriors conquering a town (an event noted by the warriors’ drawn weapons and the arrow piercing the hill). Above each participant’s head is a glyph, or pictograph , with a dot. The glyphs below the warriors are calendrical day signs. They are also, however, the names of Mixtec nobles; among this group, a person’s name was often his or her birthday.
Pre-Columbian Mixtec are mainly concerned with histories. They record events such as royal births, wars and battles, royal marriages, forging of alliances, pilgrimages , and death of rulers. In addition to the calendrical signs used for dating events and naming individuals, the Mixtecs used a combination of conventionalized pictures and glyphs to illustrate the type and nature of the event. One example is the wedding scene, usually shown as two individuals of opposite sex facing each other and sitting on jaguar-pelt chairs, as illustrated by a scene from the Codex Zouche-Nuttall which records the marriage of the legendary Mixtec King 8 Deer “Tiger Claw” of Tilantongo to Lady 12 Snake in 1051 CE.
This arrangement of the bride and groom is a purely pictorial convention, with no connection to the language. This means that no idiom or phrase in the Mixtec language that describing two people sitting face-to-face is a metaphor for marriage. However, the cup of chocolate held by Lady 12 Snake may represent the expression ynodzehua , which means “dowry” in Mixtec, where the root dzehua means “chocolate.” Chocolate or cacao was one of the most expensive and luxurious products in Mesoamerica, and cacao beans were used as currency. It is no surprise the word for dowry would be based on chocolate.
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25.11: Cell-Surface Carbohydrates and Influenza Viruses
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- Chris Schaller, Steven Farmer, & Dietmar Kennepohl
- University of Illinois Springfield
Objectives
After completing this section, you should be able to:
- Explain how carbohydrates are related to blood type.
- Explain how influenza works and how it is influenced by carbohydrates.
Oligosaccharides
An oligosaccharide is a saccharide polymer containing a small number (typically two to ten) of monosaccharides. Oligosaccharides can have many functions; for example, they are commonly found on the plasma membrane of animal cells where they can play a role in cell-cell recognition. In general, they are found attached to compatible amino acid side-chains in proteins or to lipids. Oligosaccharides are often found as a component of glycoproteins or glycolipids . They can be used as chemical markers on the outside of cells, often for cell recognition. Oligosaccharides are also responsible for determining blood type.
Glycoproteins
Carbohydrates are covalently attached to many different biomolecules, including lipids, to form glycolipids, and proteins, to form glycoproteins. Glycoproteins and glycolipids are often found in biological membranes, to which they are anchored by through nonpolar interactions. What is the function of these carbohydrates? Two are apparent. First, glycosylation of proteins helps protect the protein from degradation by enzyme catalysts within the body. However, their main functions arises from the fact that covalently attached carbohydrates that "decorate" the surface of glycoproteins or glycolipids provide new binding site interactions that allow interactions with other biomolecules. Hence glycosylation allows for cell:cell, cell:protein, or protein:protein interactions. Unfortunately, bacteria and viruses often recognize glycosylated molecules on cell membranes as well, allowing for their import into the cell.
Blood Type
Cell markers are carbohydrate chains on the surface of cells where they act as “road signs” allowing molecules to distinguish one cell from another. Blood markers are exclusively made from four monosaccharides: D-galactose, L-fucose, N-acetylgalactosamine, and N-acetylglucosamine.
ABO blood markers found on red blood cells are made up of oligosaccharides that contain either three or four sugar units as shown below. Oligosaccharides attached to red blood cells determine the ABO blood type.
Of the four blood types, type O has the fewest types of saccharides attached to it while type AB has the most. As a result, type O blood is considered the universal donor because it doesn't have any saccharides present that will appear as foreign when transfused into blood of another type. The reverse is not true. For example:
- If type A blood is given to a patient with type O blood, it will be rejected by the body because there is an unknown species being introduced to the body. Type A blood cells contain N-acetylgalactosamine which is not present in type O blood.
- Since type AB blood has all possible saccharides, type AB blood is considered the universal acceptor .
The Rhesus factor (Rh) in blood also affects donor and acceptor properties but it does not depend on carbohydrates. The Rh factor is determined by the presence (Rh+) or absence (Rh-) of a specific protein on the surface of red blood cells.
Influenza and the Avian Flu
Three pandemics of influenza have swept the world since the "Spanish" flu of 1918.
- The "Asian" flu pandemic of 1957;
- the "Hong Kong" flu pandemic of 1968;
- the "Swine" flu pandemic that began in April of 2009.
The influenza virus is a simple yet deadly virus. It interacts with human cells through a surface protein, hemagglutinin (HA). The virus binds to host cells through interaction of HA with cell surface carbohydrates. Once bound the virus internalizes, ultimately leading to release of the RNA genome of the virus into the host cell. The HA protein is the most abundant protein on the viral surface (as surmised by antibody formation).
The influenza virus is typically classified by two kinds of glycoproteins on the surface of the virus: in addition to HA is the enzyme neuraminidase. Two viral strains which have been often discussed are H5N1 and H1N1 which stands for hemagglutinin (H: type 5 or type 1) and neuraminidase (N: type 1). 15 avian and mammalian variants have been identified (based on antibody studies). Only 3 adapted to humans in the last 100 yr, giving pandemic strains H1 (1918), H2 (957) and H3 (1968). Three recent avian variants (H5, H7, and H9) have jumped directly to humans recently but have low human to human transmissibility.
Influenza Virus binds to Cell Surface Glycoproteins with Neu5Ac - A protein on the surface of influenza virus. Hemagluttinin binds to sialic acid (Sia), which is covalently attached to many cell membrane glycoproteins. The sialic acid is usually connected through an alpha (2,3) or alpha (2,6) link to galactose on N-linked glycoproteins. The subtypes found in avian (and equine) influenza isolates bind preferentially to Sia (alpha 2,3) Gal which predominates in avian GI tract where viruses replicate. Human virus of H1, H2, and H3 subtype (cause of the 1918, 1957, and 1968 pandemics) recognize Sia (alpha 2,6) Gal, as the major form in the human respiratory tract. The swine influenza HA bind to Sia (alpha 2,6) Gal and some Sia (alpha 2,3) both of which are commonly found in swine.
The virus, before it leaves the cell, forms a bud on the intracellular side of the cell with the HA and NA in the cell membrane of the host cell. The virus in this state would not leave the cell since its HA molecules would interact with sialic acid residues in the host cell membrane, holding the virus in the membrane. Neuraminidase hydrolyzes sialic acid from cell surface glycoproteins, allowing the virus to complete the budding process and be released from the cell as new viruses. By mimicking the structure of sialic acid, the drugs Oseltamivir (Tamiflu) and zanamivir (Relenza) bind to and inhibit neuraminidase whose activity is necessary for viral release from infected cells. Tamiflu appears to work against N1 of the present H5N1 avian influenza viruses. Governments across the world are stockpiling this drug in case of a pandemic caused by the avian virus jumping directly to humans and becoming transmissible from human to human.


4.4: Person, Gender, and Cultural Differences in Conformity
Person Differences
Even in cases in which the pressure to conform is strong and a large percentage of individuals do conform (such as in Solomon Asch’s line-judging research), not everyone does so. There are usually some people willing and able to go against the prevailing norm. In Asch’s study, for instance, despite the strong situational pressures, 24% of the participants never conformed on any of the trials.
People prefer to have an “optimal” balance between being similar to, and different from, others (Brewer, 2003). When people are made to feel too similar to others, they tend to express their individuality, but when they are made to feel too different from others, they attempt to increase their acceptance by others. Supporting this idea, research has found that people who have lower self-esteem are more likely to conform in comparison with those who have higher self-esteem. This makes sense because self-esteem rises when we know we are being accepted by others, and people with lower self-esteem have a greater need to belong. And people who are dependent on and who have a strong need for approval from others are also more conforming (Bornstein, 1992).
Age also matters, with individuals who are either younger or older being more easily influenced than individuals who are in their 40s and 50s (Visser & Krosnick, 1998). People who highly identify with the group that is creating the conformity are also more likely to conform to group norms, in comparison to people who don’t really care very much (Jetten, Spears, & Manstead, 1997; Terry & Hogg, 1996).
However, although there are some differences among people in terms of their tendency to conform (it has even been suggested that some people have a “need for uniqueness” that leads them to be particularly likely to resist conformity; Snyder & Fromkin, 1977), research has generally found that the impact of person variables on conformity is smaller than the influence of situational variables, such as the number and unanimity of the majority.
Gender Differences
Several reviews and meta-analyses of the existing research on conformity and leadership in men and women have now been conducted, and so it is possible to draw some strong conclusions in this regard. In terms of conformity, the overall conclusion from these studies is that that there are only small differences between men and women in the amount of conformity they exhibit, and these differences are influenced as much by the social situation in which the conformity occurs as by gender differences themselves.
On average, men and women have different levels of self-concern and other-concern. Men are, on average, more concerned about appearing to have high status and may be able to demonstrate this status by acting independently from the opinions of others. On the other hand, and again although there are substantial individual differences among them, women are, on average, more concerned with connecting to others and maintaining group harmony. Taken together, this means that, at least when they are being observed by others, men are likely to hold their ground, act independently, and refuse to conform, whereas women are more likely to conform to the opinions of others in order to prevent social disagreement. These differences are less apparent when the conformity occurs in private (Eagly, 1978, 1983).
The observed gender differences in conformity have social explanations—namely that women are socialized to be more caring about the desires of others—but there are also evolutionary explanations. Men may be more likely to resist conformity to demonstrate to women that they are good mates. Griskevicius, Goldstein, Mortensen, Cialdini, and Kenrick (2006) found that men, but not women, who had been primed with thoughts about romantic and sexual attraction were less likely to conform to the opinions of others on a subsequent task than were men who had not been primed to think about romantic attraction.
In addition to the public versus private nature of the situation, the topic being discussed also is important, with both men and women being less likely to conform on topics that they know a lot about, in comparison with topics on which they feel less knowledgeable (Eagly & Chravala, 1986). When the topic is sports, women tend to conform to men, whereas the opposite is true when the topic is fashion. Thus it appears that the small observed differences between men and women in conformity are due, at least in part, to informational influence.
Because men have higher status in most societies, they are more likely to be perceived as effective leaders (Eagly, Makhijani, & Klonsky, 1992; Rojahn & Willemsen, 1994; Shackelford, Wood, & Worchel, 1996). And men are more likely to be leaders in most cultures. For instance, women hold only about 20% of the key elected and appointed political positions in the world (World Economic Forum, 2013). There are also more men than women in leadership roles, particularly in high-level administrative positions, in many different types of businesses and other organizations. Women are not promoted to positions of leadership as fast as men are in real working groups, even when actual performance is taken into consideration (Geis, Boston, & Hoffman, 1985; Heilman, Block, & Martell, 1995).
Men are also more likely than women to emerge and act as leaders in small groups, even when other personality characteristics are accounted for (Bartol & Martin, 1986; Megargee, 1969; Porter, Geis, Cooper, & Newman, 1985). In one experiment, Nyquist and Spence (1986) had pairs of same- and mixed-sex students interact. In each pair there was one highly dominant and one low dominant individual, as assessed by previous personality measures. They found that in pairs in which there was one man and one woman, the dominant man became the leader 90% of the time, but the dominant woman became the leader only 35% of the time.
Keep in mind, however, that the fact that men are perceived as effective leaders, and are more likely to become leaders, does not necessarily mean that they are actually better, more effective leaders than women. Indeed, a meta-analysis studying the effectiveness of male and female leaders did not find that there were any gender differences overall (Eagly, Karau, & Makhijani, 1995) and even found that women excelled over men in some domains. Furthermore, the differences that were found tended to occur primarily when a group was first forming but dissipated over time as the group members got to know one another individually.
One difficulty for women as they attempt to lead is that traditional leadership behaviors, such as showing independence and exerting power over others, conflict with the expected social roles for women. The norms for what constitutes success in corporate life are usually defined in masculine terms, including assertiveness or aggressiveness, self-promotion, and perhaps even macho behavior. It is difficult for women to gain power because to do so they must conform to these masculine norms, and often this goes against their personal beliefs about appropriate behavior (Rudman & Glick, 1999). And when women do take on male models of expressing power, it may backfire on them because they end up being disliked because they are acting nonstereotypically for their gender. A recent experimental study with MBA students simulated the initial public offering (IPO) of a company whose chief executive was either male or female (personal qualifications and company financial statements were held constant across both conditions). The results indicated a clear gender bias as female chief executive officers were perceived as being less capable and having a poorer strategic position than their male counterparts. Furthermore, IPOs led by female executives were perceived as less attractive investments (Bigelow, Lundmark, McLean Parks, & Wuebker, 2012). Little wonder then that women hold fewer than 5% of Fortune 500 chief executive positions.
One way that women can react to this “double-bind” in which they must take on masculine characteristics to succeed, but if they do they are not liked, is to adopt more feminine leadership styles, in which they use more interpersonally oriented behaviors such as agreeing with others, acting in a friendly manner, and encouraging subordinates to participate in the decision-making process (Eagly & Johnson, 1990; Eagly et al., 1992; Wood, 1987). In short, women are more likely to take on a transformational leadership style than are men—doing so allows them to be effective leaders while not acting in an excessively masculine way (Eagly & Carli, 2007; Eagly, Johannesen-Schmidt, & van Egen, 2003).
In sum, women may conform somewhat more than men, although these differences are small and limited to situations in which the responses are made publicly. In terms of leadership effectiveness, there is no evidence that men, overall, make better leaders than do women. However, men do better as leaders on tasks that are “masculine” in the sense that they require the ability to direct and control people. On the other hand, women do better on tasks that are more “feminine” in the sense that they involve creating harmonious relationships among the group members.
Cultural Differences
In addition to gender differences, there is also evidence that conformity is greater in some cultures than others. Your knowledge about the cultural differences between individualistic and collectivistic cultures might lead you to think that collectivists will be more conforming than individualists, and there is some support for this. Bond and Smith (1996) analyzed results of 133 studies that had used Asch’s line-judging task in 17 different countries. They then categorized each of the countries in terms of the degree to which it could be considered collectivist versus individualist in orientation. They found a significant relationship: conformity was greater in more collectivistic than in individualistic countries.
Kim and Markus (1999) analyzed advertisements from popular magazines in the United States and in Korea to see if they differentially emphasized conformity and uniqueness. As you can see in [the figure], “Culture and Conformity,” they found that while U.S. magazine ads tended to focus on uniqueness (e.g., “Choose your own view!”; “Individualize”) Korean ads tended to focus more on themes of conformity (e.g., “Seven out of 10 people use this product”; “Our company is working toward building a harmonious society”).
Kim and Markus (1999) found that U.S. magazine ads tended to focus on uniqueness whereas Korean ads tended to focus more on conformity.
In summary, although the effects of individual differences on conformity tend to be smaller than those of the social context, they do matter. And gender and cultural differences can also be important. Conformity, like most other social psychological processes, represents an interaction between the situation and the person.
Psychological Reactance
Conformity is usually quite adaptive overall, both for the individuals who conform and for the group as a whole. Conforming to the opinions of others can help us enhance and protect ourselves by providing us with important and accurate information and can help us better relate to others. Following the directives of effective leaders can help a group attain goals that would not be possible without them. And if only half of the people in your neighborhood thought it was appropriate to stop on red and go on green but the other half thought the opposite—and behaved accordingly—there would be problems indeed.
But social influence does not always produce the intended result. If we feel that we have the choice to conform or not conform, we may well choose to do so in order to be accepted or to obtain valid knowledge. On the other hand, if we perceive that others are trying to force or manipulate our behavior, the influence pressure may backfire, resulting in the opposite of what the influencer intends.
Consider an experiment conducted by Pennebaker and Sanders (1976), who attempted to get people to stop writing graffiti on the walls of campus restrooms. In some restrooms they posted a sign that read “Do not write on these walls under any circumstances!” whereas in other restrooms they placed a sign that simply said “Please don’t write on these walls.” Two weeks later, the researchers returned to the restrooms to see if the signs had made a difference. They found that there was much less graffiti in the second restroom than in the first one. It seems as if people who were given strong pressures to not engage in the behavior were more likely to react against those directives than were people who were given a weaker message.
When individuals feel that their freedom is being threatened by influence attempts and yet they also have the ability to resist that persuasion, they may experience psychological reactance , a strong motivational state that resists social influence (Brehm, 1966; Miron & Brehm, 2006). Reactance is aroused when our ability to choose which behaviors to engage in is eliminated or threatened with elimination. The outcome of the experience of reactance is that people may not conform or obey at all and may even move their opinions or behaviors away from the desires of the influencer.
Reactance represents a desire to restore freedom that is being threatened. And an adult who feels that she is being pressured by a car sales representative might feel the same way and leave the showroom entirely, resulting in the opposite of the sales rep’s intended outcome.
Of course, parents are sometimes aware of this potential, and even use “reverse psychology”—for example, telling a child that he or she cannot go outside when they really want the child to do so, hoping that reactance will occur. In the musical The Fantasticks , neighboring fathers set up to make the daughter of one of them and the son of the other fall in love with each other by building a fence between their properties. The fence is seen by the children as an infringement on their freedom to see each other, and as predicted by the idea of reactance, they ultimately fall in love.
In addition to helping us understand the affective determinants of conformity and of failure to conform, reactance has been observed to have its ironic effects in a number of real-world contexts. For instance, Wolf and Montgomery (1977) found that when judges give jury members instructions indicating that they absolutely must not pay any attention to particular information that had been presented in a courtroom trial (because it had been ruled as inadmissible), the jurors were more likely to use that information in their judgments. And Bushman and Stack (1996) found that warning labels on violent films (for instance, “This film contains extreme violence—viewer discretion advised”) created more reactance (and thus led participants to be more interested in viewing the film) than did similar labels that simply provided information (“This film contains extreme violence”). In another relevant study, Kray, Reb, Galinsky, and Thompson (2004) found that when women were told that they were poor negotiators and would be unable to succeed on a negotiation task, this information led them to work even harder and to be more successful at the task.
Finally, within clinical therapy, it has been argued that people sometimes are less likely to try to reduce the harmful behaviors that they engage in, such as smoking or drug abuse, when the people they care about try too hard to press them to do so (Shoham, Trost, & Rohrbaugh, 2004). One patient was recorded as having reported that his wife kept telling him that he should quit drinking, saying, “If you loved me enough, you’d give up the booze.” However, he also reported that when she gave up on him and said instead, “I don’t care what you do anymore,” he then enrolled in a treatment program (Shoham et al., 2004, p. 177).
Person, gender, and cultural differences in conformity are important in a law enforcement context for the reasons discussed below.
Citizens may not obey a lawful order by a police officer when the officer uses power lawfully. This may occur when the citizen perceives the officer is eliminating the citizen’s right to engage in the behavior they wish to. This, according to Dr. Rajiv Jhangiani and Dr. Hammond Tarry, may lead people not to conform, or obey an order, and may indeed lead the citizen to oppose the officer who is trying to make a lawful order.
Furthermore, while person variables may predict conformity, situational variables are usually more important. This would suggest that the behavior and action of the officers may have a strong role to play in determining whether or not the citizen will conform.
Text Attribution
The following discussion comes from the chapter “ Person, Gender, and Cultural Differences in Conformity” from the textbook Principles of Social Psychology: 1st International Edition. and is licensed CC BY 4.0 . All references cited on this page can be found at the end of the chapter “ Person, Gender, and Cultural Differences in Conformity”
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- Culture and Conformity © "Principles of Social Psychology"


2.4: The many modes of capability analysis
If the capability approach is an open framework, then what are the ways in which it has been closed to form more specific and powerful analyses? Scholars use the capability approach for different types of analysis, with different goals, relying on different methodologies, with different corresponding roles for functionings and capabilities. Not all of these are capability theories ; some are capability applications , both empirical as well as theoretical. We can observe that there is a rich diversity of ways in which the capability approach has been used. Table 2.1 gives an overview of these different usages, by listing the different types of capability analyses.
Normative theorising within the capability approach is often done by moral and political philosophers. The capability approach is then used as one element of a normative theory, such as a theory of justice or a theory of disadvantage. For example, Elizabeth Anderson (1999) has proposed the outlines of a theory of social justice (which she calls “democratic equality”) in which certain basic levels of capabilities that are needed to function as equal citizens should be guaranteed to all. Martha Nussbaum (2006b) has developed a minimal theory of social justice in which she defends a list of basic capabilities that everyone should be entitled to, as a matter of human dignity.
While most normative theorising within the capability approach has related to justice, other values have also been developed and analysed using the capability approach. Some theorists of freedom have developed accounts of freedom or rights using the capability approach (van Hees 2013). Another important value that has been studied from the perspective of the capability approach is ecological sustainability (e.g. Anand and Sen 1994, 2000; Robeyns and Van der Veen 2007; Lessmann and Rauschmayer 2013; Crabtree 2013; Sen 2013). Efficiency is a value about which very limited conceptual work is done, but which nevertheless is inescapably normative, and it can be theorised in many different ways (Le Grand 1990; Heath 2006). If we ask what efficiency is, we could answer by referring to Pareto optimality or x-efficiency, but we could also develop a notion of efficiency from a capability perspective (Sen 1993b). Such a notion would answer the question ‘efficiency of what?’ with ‘efficiency in the space of capabilities (or functionings, or a mixture)’.
Table 2.1 The main modes of capability analysis
| Epistemic goal | Methodology/discipline | Role of functionings and capabilities | Examples |
| Normative theories (of particular values), e.g. theories of justice, human rights, wellbeing, sustainability, efficiency, etc. | Philosophy, in particular ethics and normative political philosophy. | The metric/currency in the interpersonal comparisons of advantage that are entailed in the value that is being analysed. | Sen 1993b; Anand and Sen 1994; Crabtree 2012, 2013; Lessmann and Rauschmayer 2013; Robeyns 2016c; Nussbaum 1992, 1997; Nussbaum 2000; Nussbaum 2006b; Wolff and De-Shalit 2007. |
| Normative applied analysis, including policy design. | Applied ethics (e.g. medical ethics, bio-ethics, economic ethics, development ethics etc.) and normative strands in the social sciences. | A metric of individual advantage that is part of the applied normative analysis. | Alkire 2002; Robeyns 2003; Canoy, Lerais and Schokkaert 2010; Holland 2014; Ibrahim 2017. |
| Welfare/quality of life measurement. | Quantitative empirical strands within various social sciences. | Social indicators. | Kynch and Sen 1983; Sen 1985a; Kuklys 2005; Alkire and Foster 2011; Alkire et al. 2015; Chiappero-Martinetti 2000. |
| Thick description/descriptive analysis. | Quantitative empirical strands within various social sciences. | Elements of a narrative. | Unterhalter 2003b; Conradie 2013. |
| Understanding the nature of certain ideas, practices, notions (other than the values in the normative theories). | Conceptual analysis. | Used as part of the conceptualisation of the idea or notion. | Sen 1993b; Robeyns 2006c; Wigley and Akkoyunlu-Wigley 2006; van Hees 2013. |
| [Other goals?] | [Other methods?] | [Other roles?] | [Other studies may be available/are needed.] |
Source: Robeyns (2005a), expanded and updated.
Quantitative social scientists, especially economists, are mostly interested in measurement. This quantitative work could serve different purposes, e.g. the measurement of multidimensional poverty analysis (Alkire and Foster 2011; Alkire et al. 2015), or the measurement of the disadvantages faced by disabled people (Kuklys 2005; Zaidi and Burchardt 2005). Moreover, some quantitative social scientists, mathematicians, and econometricians have been working on investigating the methods that could be used for quantitative capability analyses (Kuklys 2005; Di Tommaso 2007; Krishnakumar 2007; Krishnakumar and Ballon 2008; Krishnakumar and Nagar 2008).
Thick description or descriptive analysis is another mode of capability analysis. For example, it can be used to describe the realities of schoolgirls in countries that may have formal access to school for both girls and boys, but where other hurdles (such as high risk of rape on the way to school, or the lack of sanitary provisions at school) mean that this formal right is not enough to guarantee these girls the corresponding capability (Unterhalter 2003b).
Finally, the capability approach can be used for conceptual work beyond the conceptualisation of values, as is done within normative philosophy. Sometimes the capability approach lends itself well to providing a better understanding of a certain phenomenon. For example, we could understand education as a legal right or as an investment in human capital, but we could also conceptualise it as the expansion of a capability, or develop an account of education that draws on both the capability approach and human rights theory. This would not only help us to look differently at what education is; a different conceptualisation would also have normative implications, for example related to the curriculum design, or to answer the question of what is needed to ensure that capability, or of how much education should be guaranteed to children with low potential market-related human capital (McCowan 2011; Nussbaum 2012; Robeyns 2006c; Walker 2012a; Walker and Unterhalter 2007; Wigley and Akkoyunlu-Wigley 2006).
Of course, texts and research projects often have multiple goals, and therefore particular studies often mix these different goals and methods. Jean Drèze and Amartya Sen’s (1996, 2002, 2013) comprehensive analyses of India’s human development achievements are in part an evaluative analysis based on various social indicators, but also in part a prescriptive analysis. Similarly, Nussbaum’s (2000) book Women and Human Development is primarily normative and philosophical, but also includes thick descriptions of how institutions enable or hamper people’s capabilities, by focussing on the lives of particular women.
What is the value of distinguishing between different uses of the capability approach? It is important because functionings and capabilities — the core concepts in the capability approach — play different roles in each type of analysis. In quality of life measurement, the functionings and capabilities are the social indicators that reflect a person’s quality of life. In thick descriptions and descriptive analysis, the functionings and capabilities form part of the narrative. This narrative can aim to reflect the quality of life, but it can also aim to understand some other aspect of people’s lives, such as by explaining behaviour that might appear irrational according to traditional economic analysis, or revealing layers of complexities that a quantitative analysis can rarely capture. In philosophical reasoning, the functionings and capabilities play yet another role, as they are often part of the foundations of a utopian account of a just society or of the goals that morally sound policies should pursue.
The flexibility of functionings and capabilities, which can be applied in different ways within different types of capability analysis, means that there are no hard and fast rules that govern how to select the relevant capabilities. Each type of analysis, with its particular goals, will require its own answer to this question. The different roles that functionings and capabilities can play in different types of capability analyses have important implications for the question of how to select the relevant capabilities: each type of analysis, with its particular goals, will require its own answer to this question. The selection of capabilities as social indicators of the quality of life is a very different undertaking from the selection of capabilities for a utopian theory of justice: the quality standards for research and scholarship are different, the epistemic constraints of the research are different, the best available practices in the field are different. Moral philosophers, quantitative social scientists, and qualitative social scientists have each signed up to a different set of meta-theoretical assumptions, and find different academic practices acceptable and unacceptable. For example, many ethnographers tend to reject normative theorising and also often object to what they consider the reductionist nature of quantitative empirical analysis, whereas many economists tend to discard the thick descriptions by ethnographers, claiming they are merely anecdotal and hence not scientific.
Two remarks before closing this section. First, providing a typology of the work on the capability approach, as this section attempts to do, remains work in progress. In 2004, I could only discern three main modes of capability analysis: quality of life analysis; thick description/descriptive analysis; and normative theories — though I left open the possibility that the capability approach could be used for other goals too (Robeyns 2005a). In her book Creating Capabilities , Nussbaum (2011) writes that the capability approach comes in only two modes: comparative qualify of life assessment, and as a theory of justice. I don’t think that is correct: not all modes of capability analysis can be reduced to these two modes, as I have argued elsewhere in detail (Robeyns 2011, 2016b). The different modes of capability analysis described in table 2.1 provide a more comprehensive overview, but we should not assume that this overview is complete. It is quite likely that table 2.1 will, in due course, have to be updated to reflect new types of work that uses the capability approach. Moreover, one may also prefer another way to categorise the different types of work done within the capability literature, and hence other typologies are possible and may be more illuminating.
Second, it is important that we fully acknowledge the diversity of disciplines, the diversity of goals we have for the creation of knowledge, and the diversity of methods used within the capability approach. At the same time, we need not forget that some aspects of its development might need to be discipline-specific, or specific for one’s goals. As a result, the capability approach is at the same time multidisciplinary, interdisciplinary, but also forms part of developments within disciplines and methods. These different ‘faces’ of the capability approach all need to be fully acknowledged if we want to understand it in a nuanced and complete way.


13.2: The Nature of NMR Absorptions
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Objectives
After completing this section, you should be able to
- explain, in general terms, the origin of shielding effects in NMR spectroscopy.
- explain the number of peaks occurring in the 1 H or 13 C NMR spectrum of a simple compound, such as methyl acetate.
- describe, and sketch a diagram of, a simple NMR spectrometer.
- explain the difference in time scales of NMR and infrared spectroscopy.
- predict the number of peaks expected in the 1 H or 13 C NMR spectrum of a given compound.
Study Notes
Before you go on, make sure that you understand that each signal in the 1 H NMR spectrum shown for methyl acetate is due to a different proton environment. The three protons on the same methyl group are equivalent and appear in the spectrum as one signal. However, the two methyl groups are in two different environments (one is more deshielded) and so we see two signals in the whole spectrum (aside from the TMS reference peak).
Methyl acetate has a very simple 1 H NMR spectrum, because there is no proton-proton coupling, and therefore no splitting of the signals. In later sections, we discuss splitting patterns in 1 H NMR spectra and how they help a chemist determine the structure of organic compounds.
Nuclear precession, spin states, and the resonance condition
When a sample of an organic compound is sitting in a flask on a laboratory benchtop, the magnetic moments of its hydrogen atoms are randomly oriented. When the same sample is placed within the field of a very strong magnet in an NMR instrument (this field is referred to by NMR spectroscopists as the applied field , abbreviated B 0 ) each hydrogen will assume one of two possible spin states . In what is referred to as the +½ spin state, the hydrogen's magnetic moment is aligned with the direction of B 0 , while in the -½ spin state it is aligned opposed to the direction of B 0 .
Because the +½ spin state is slightly lower in energy, in a large population of organic molecules slightly more than half of the hydrogen atoms will occupy this state, while slightly less than half will occupy the –½ state. T he difference in energy between the two spin states increases with increasing strength of B 0 . This last statement is in italics because it is one of the key ideas in NMR spectroscopy, as we shall soon see.
At this point, we need to look a little more closely at how a proton spins in an applied magnetic field. You may recall playing with spinning tops as a child. When a top slows down a little and the spin axis is no longer completely vertical, it begins to exhibit precessional motion , as the spin axis rotates slowly around the vertical. In the same way, hydrogen atoms spinning in an applied magnetic field also exhibit precessional motion about a vertical axis. It is this axis (which is either parallel or antiparallel to B 0 ) that defines the proton’s magnetic moment. In the figure below, the proton is in the +1/2 spin state.
The frequency of precession (also called the Larmour frequency, abbreviated ω L ) is simply the number of times per second that the proton precesses in a complete circle. A proton`s precessional frequency increases with the strength of B 0 .
If a proton that is precessing in an applied magnetic field is exposed to electromagnetic radiation of a frequency ν that matches its precessional frequency ω L , we have a condition called resonance . In the resonance condition, a proton in the lower-energy +½ spin state (aligned with B 0 ) will transition (flip) to the higher energy –½ spin state (opposed to B 0 ). In doing so, it will absorb radiation at this resonance frequency ν = ω L . This frequency, as you might have already guessed, corresponds to the energy difference between the proton’s two spin states. With the strong magnetic fields generated by the superconducting magnets used in modern NMR instruments, the resonance frequency for protons falls within the radio-wave range, anywhere from 100 MHz to 800 MHz depending on the strength of the magnet.
The basics of an NMR experiment
So far, you may have the impression that all 1 H nuclei in a molecule would absorb the same frequency. However, this would be of little use to organic chemists if that were the case. It turns out that not all 1 H nuclei absorb the same frequency and this is the same for all other NMR active nuclei. It turns out that chemically nonequivalent protons (or other nuclei) have different resonance frequencies in the same applied magnetic field. Nonequivalent protons are in different chemical environments. This allows NMR spectroscopy to provide us with useful information about the structure of an organic molecule.  First, a sample compound (we'll use methyl acetate) is placed inside a very strong applied magnetic field (B 0 ). There are two types of protons in methyl acetate. H a are bonded to a C that is then bonded to a carbonyl, whereas H b are bonded to a carbon that is then bonded to an oxygen atom. This difference in bonding leads to different types of environments for H a and H b . All the H a protons are the same since they all have the same type of bonding and will be in the same chemical environment and the same is true for H b .
The basic arrangement of an NMR spectrometer is displayed below. A sample (in a small glass tube, where the methyl acetate is in solution) is placed between the poles of a strong magnet. A radio frequency generator pulses the sample and excites the nuclei causing a spin-flip. The spin flip is detected by the detector and the signal sent to a computer where it is processed.
In the magnet, all of the protons begin to precess: the H a protons at precessional frequency ω a , the H b protons at ω b . At first, the magnetic moments of (slightly more than) half of the protons are aligned with B 0 , and half (slightly less than half) are aligned against B 0 . Then, the sample is hit with electromagnetic radiation in the radio frequency range. The two specific frequencies which match ω a and ω b (i.e. the resonance frequencies) cause those H a and H b protons which are aligned with B 0 to 'flip' so that they are now aligned against B 0 . In doing so, the protons absorb radiation at the two resonance frequencies. The NMR instrument records which frequencies were absorbed, as well as the intensity of each absorbance.
In most cases, a sample being analyzed by NMR is in solution. If we used a common laboratory solvent (diethyl ether, acetone, dichloromethane, ethanol, water, etc.) to dissolve our NMR sample, however, we run into a problem – there many more solvent protons in solution than there are sample protons, therefore the signals from the sample protons will be overwhelmed. To get around this problem, we use special NMR solvents in which all protons have been replaced by deuterium. Recall that deuterium is NMR-active, but its resonance frequency is very different from that of protons, and thus it is `invisible` in 1 H-NMR. Some common NMR solvents are shown below. There are multiple deuterated solvents since molecules have different solubilities, so one molecule may dissolve in deuterated chloroform while others may not.
The Chemical Shift
Let's look at an actual 1 H-NMR plot for methyl acetate. Just as in IR and UV-vis spectroscopy, the vertical axis corresponds to intensity of absorbance, the horizontal axis to frequency (typically the vertical axis is not shown in an NMR spectrum).
We see three absorbance signals: two of these correspond to H a and H b , while the peak at the far right of the spectrum corresponds to the 12 chemically equivalent protons in tetramethylsilane (TMS), a standard reference compound that was added to our sample.
You may be wondering about a few things at this point - why is TMS necessary, and what is the meaning of the `ppm ( δ )` label on the horizontal axis? Shouldn't the frequency units be in Hz? Keep in mind that NMR instruments of many different applied field strengths are used in organic chemistry laboratories, and that the proton's resonance frequency range depends on the strength of the applied field. The spectrum above was generated on an instrument with an applied field of approximately 7.1 Tesla, at which strength protons resonate in the neighborhood of 300 million Hz (chemists refer to this as a 300 MHz instrument). If our colleague in another lab takes the NMR spectrum of the same molecule using an instrument with a 2.4 Tesla magnet, the protons will resonate at around 100 million Hz (so we’d call this a 100 MHz instrument). It would be inconvenient and confusing to always have to convert NMR data according to the field strength of the instrument used. Therefore, chemists report resonance frequencies not as absolute values in Hz, but rather as values relative to a common standard , generally the signal generated by the protons in TMS. This is where the ppm – parts per million – term comes in. Regardless of the magnetic field strength of the instrument being used, the resonance frequency of the 12 equivalent protons in TMS is defined as a zero point. The resonance frequencies of protons in the sample molecule are then reported in terms of how much higher they are, in ppm, relative to the TMS signal (almost all protons in organic molecules have a higher resonance frequency than those in TMS, for reasons we shall explore quite soon).
The two proton groups in our methyl acetate sample are recorded as resonating at frequencies 2.05 and 3.67 ppm higher than TMS. One-millionth (1.0 ppm) of 300 MHz is 300 Hz. Thus 2.05 ppm, on this instrument, corresponds to 615 Hz, and 3.67 ppm corresponds to 1101 Hz. If the TMS protons observed by our 7.1 Tesla instrument resonate at exactly 300,000,000 Hz, this means that the protons in our ethyl acetate samples are resonating at 300,000,615 and 300,001,101 Hz, respectively. Likewise, if the TMS protons in our colleague's 2.4 Tesla instrument resonate at exactly 100 MHz, the methyl acetate protons in her sample resonate at 100,000,205 and 100,000,367 Hz (on the 100 MHz instrument, 1.0 ppm corresponds to 100 Hz). The absolute frequency values in each case are not very useful – they will vary according to the instrument used – but the difference in resonance frequency from the TMS standard, expressed in parts per million, should be the same regardless of the instrument.
Expressed this way, the resonance frequency for a given proton in a molecule is called its chemical shift . A frequently used symbolic designation for chemical shift in ppm is the lower-case Greek letter delta ( δ) . Most protons in organic compounds have chemical shift values between 0 and 12 ppm from TMS, although values below zero and above 12 are occasionally observed. By convention, the left-hand side of an NMR spectrum (higher chemical shift) is called downfield , and the right-hand direction is called upfield .
In our methyl acetate example we included for illustrative purposes a small amount of TMS standard directly in the sample, as was the common procedure for determining the zero point with older NMR instruments．That practice is generally no longer necessary, as modern NMR instruments are designed to use the deuterium signal from the solvent as a standard reference point, then to extrapolate the 0 ppm baseline that corresponds to the TMS proton signal (in an applied field of 7.1 Tesla, the deuterium atom in CDCl 3 resonates at 32 MHz, compared to 300 MHz for the protons in TMS). In the remaining NMR spectra that we will see in this text we will not see an actual TMS signal, but we can always assume that the 0 ppm point corresponds to where the TMS protons would resonate if they were present.
Example
A proton has a chemical shift (relative to TMS) of 4.56 ppm.
- a) What is its chemical shift, expressed in Hz, in a 300 MHz instrument? On a 200 MHz instrument?
- b) What is its resonance frequency, expressed in Hz, in a 300 MHz instrument? On a 200 MHz instrument?
(Assume that in these instruments, the TMS protons resonate at exactly 300 or 200 MHz, respectively)
Diamagnetic shielding and deshielding
We come now to the question of why nonequivalent protons have different chemical shifts. The chemical shift of a given proton is determined primarily by its immediate electronic environment. Consider the methane molecule (CH 4 ), in which the protons have a chemical shift of 0.23 ppm. The valence electrons around the methyl carbon, when subjected to B 0 , are induced to circulate and thus generate their own very small magnetic field that opposes B 0 . This induced field , to a small but significant degree, shields the nearby protons from experiencing the full force of B 0 , an effect known as local diamagnetic shielding . The methane protons therefore do not experience the full force of B 0 - what they experience is called B eff , or the effective field , which is slightly weaker than B 0 .
Therefore, their resonance frequency is slightly lower than what it would be if they did not have electrons nearby to shield them.
Now consider methyl fluoride, CH 3 F, in which the protons have a chemical shift of 4.26 ppm, significantly higher than that of methane. This is caused by something called the deshielding effect . Because fluorine is more electronegative than carbon, it pulls valence electrons away from the carbon, effectively decreasing the electron density around each of the protons. For the protons, lower electron density means less diamagnetic shielding, which in turn means a greater overall exposure to B 0 , a stronger B eff , and a higher resonance frequency. Put another way, the fluorine, by pulling electron density away from the protons, is deshielding them, leaving them more exposed to B 0 . As the electronegativity of the substituent increases, so does the extent of deshielding, and so does the chemical shift. This is evident when we look at the chemical shifts of methane and three halomethane compounds (remember that electronegativity increases as we move up a column in the periodic table).
To a large extent, then, we can predict trends in chemical shift by considering how much deshielding is taking place near a proton. The chemical shift of trichloromethane is, as expected, higher than that of dichloromethane, which is in turn higher than that of chloromethane.
The deshielding effect of an electronegative substituent diminishes sharply with increasing distance:
The presence of an electronegative oxygen, nitrogen, sulfur, or sp 2 -hybridized carbon also tends to shift the NMR signals of nearby protons slightly downfield:
Table 2 lists typical chemical shift values for protons in different chemical environments.
Armed with this information, we can finally assign the two peaks in the the 1 H-NMR spectrum of methyl acetate that we saw a few pages back. The signal at 3.65 ppm corresponds to the methyl ester protons (H b ), which are deshielded by the adjacent oxygen atom. The upfield signal at 2.05 ppm corresponds to the acetate protons (H a ), which is deshielded - but to a lesser extent - by the adjacent carbonyl group.
Finally, a note on the use of TMS as a standard in NMR spectroscopy: one of the main reasons why the TMS proton signal was chosen as a zero-point is that the TMS protons are highly shielded: silicon is slightly less electronegative than carbon, and therefore donates some additional shielding electron density. Very few organic molecules contain protons with chemical shifts that are negative relative to TMS.