carl linnaeus was the swedish scientist who developed a naming system based on organisms observable traits.
carl linnaeus was the swedish scientist who developed a naming system based on organisms observable traits.
who was the swedish scientist who developed a naming system based on organisms observable traits?
carl linnaeus
in the 18th century, the swedish scientist carl linnaeus classified organisms according to shared physical characteristics, and not simply based upon differences. he established the idea of a taxonomic hierarchy of classification based upon observable characteristics and intended to reflect natural relationships. at the time, however, it was still widely believed that there was no organic connection between species, no matter how similar they appeared. this view was influenced by european scholarly and religious education, which held that the categories of life are dictated by god, forming an aristotelian hierarchy, the "scala naturae" or great chain of being. however, whether or not it was supposed to be fixed, the "scala" (a ladder) inherently implied the possibility of climbing.
species
lee cronbach and paul meehl (1955) proposed that the development of a nomological net was essential to measurement of a test's construct validity. a nomological network defines a construct by illustrating its relation to other constructs and behaviors. it is a representation of the concepts (constructs) of interest in a study, their observable manifestations and the interrelationship among them. it examines whether the relationships between similar construct are considered with relationships between the observed measures of the constructs. thorough observation of constructs relationships to each other it can generate new constructs. for example, intelligence and working memory are considered highly related constructs. through the observation of their underlying components psychologists developed new theoretical constructs such as: controlled attention and short term loading. creating a nomological net can also make the observation and measurement of existing constructs more efficient by pinpointing errors. researchers have found that studying the bumps on the human skull (phrenology) are not indicators of intelligence, but volume of the brain is. removing the theory of phrenology from the nomological net of intelligence and adding the theory of brain mass evolution, constructs of intelligence are made more efficient and more powerful. the weaving of all of these interrelated concepts and their observable traits creates a "net" that supports their theoretical concept. for example, in the nomological network for academic achievement, we would expect observable traits of academic achievement (i.e. gpa, sat, and act scores) to relate to the observable traits for studiousness (hours spent studying, attentiveness in class, detail of notes). if they do not then there is a problem with measurement (of academic achievement or studiousness), or with the purported theory of achievement. if they are indicators of one another then the nomological network, and therefore the constructed theory, of academic achievement is strengthened. although the nomological network proposed a theory of how to strengthen constructs, it doesn't tell us how we can assess the construct validity in a study.
construct validity