headphones. the participants listen to the tones which will vary in pitch and loudness. the test will play with the volume controls and the participant is asked to signal when he or she can no longer hear the tone being played. the testing is completed after listening to a range of pitches. each ear is tested individually. during the tuning fork test, the tester will have the tuning fork vibrate so that it makes a sound. the tuning fork is placed in a specific place around the participant and hearing is observed. in some instances, individuals will show trouble hearing in places such as behind the ear. speech recognition and word recognition tests measure how well an individual can hear normal day-to-day conversation. the participant is told to repeat conversation being spoken at different volumes. the spondee threshold test is a related test that detects the loudness at which the participant is able to repeat half of a list of two syllable words or spondees. otoacoustic emissions test (oae) and auditory brainstem response (abr) testing measures the brain's response to sounds. the oae measures hearing of newborns by placing an emitting sound into the baby's ear through a probe. a microphone placed in the baby's ear canal will pick up the inner ear's response to sound stimulation and allows for observation. the abr, also known as the brainstem auditory evoked response (baer) test or auditory brainstem evoked potential (abep) test measure the brain's response to clicking sounds sent through headphones. electrodes on the scalp and earlobes record a graph of the response. taste modality taste modality in mammals in mammals, taste stimuli are encountered by axonless receptor cells located in taste buds on the tongue and pharynx. receptor cells disseminate onto different neurons and convey the message of a particular taste in a single medullar nucleus. this pheromone detection system deals with taste stimuli. the pheromone detection system is distinct from the normal taste system, and is designed like the olfactory system. taste modality in flies and mammals in insect and mammalian taste, receptor cells changes into attractive or aversive stimulus. the number of taste receptors in a mammalian tongue and on the tongue of the fly (labellum) is same in amount. most of the receptors are dedicated to detect repulsive ligand. perception perceptions of taste is generated by the following sensory afferents: gustatory, olfactory, and somatosensory fibers. taste perception is created by combining multiple sensory inputs. different modalities help determine perception of taste especially when attention is drawn to particular sensory characteristics which is different from taste. integration of taste and smell modality impression of both taste and smell occurs in heteromodal regions of the limbic and paralimbic brain. taste–odor integration occurs at earlier stages of processing. by life experience, factors such as the physiological significance of a given stimulus is perceived. learning and affective processing are the primary functions of limbic and paralimbic brain. taste perception is a combination of oral somatosensation and retronasal olfaction. pleasure of food the sensation of taste come from oral somatosensory stimulation and with retronasal olfaction. the perceived pleasure encountered when eating and drinking is influenced by: sensory features, such as taste quality experience, such as prior exposure to taste-odor mixtures internal state cognitive context, such as information about brand temperature modality description temperature modality excites or elicits a symptom through cold or hot temperature. different mammalian species have different temperature modality. perception the cutaneous somatosensory system detects changes in temperature. the perception begins when thermal stimuli from a homeostatic set-point excite temperature specific sensory nerves in the skin. then with the help of sensing range, specific thermosensory fibers respond to warmth and to cold. then specific cutaneous cold and warm receptors conduct units that exhibit a discharge at constant skin temperature. nerve fibers for temperature warm and cold sensitive nerve fibers differ in structure and function. the cold-sensitive and warm-sensitive nerve fibers are underneath the skin surface. terminals of each temperature-sensitive fiber do not branch away to different organs in the body. they form a small sensitive point which are unique from neighboring fibers. skin used by the single receptor ending of a temperature-sensitive nerve fiber is small. there are 20 cold points per square centimeter in the lips, 4 in the finger, and less than 1 cold point per square centimeter in trunk areas. there are 5 times as many cold sensitive points as warm sensitive points. pressure modality description the sense of touch, or tactile perception, is what allows organisms to feel the world around them. the environment acts as an external stimulus, and tactile perception is the act of passively exploring the world to simply sense it. to make sense of the stimuli, an organism will undergo active exploration, or haptic perception, by moving their hands or other areas with environment-skin contact. this will give a sense of what is being perceived, and give information about size, shape, weight, temperature, and material. tactile stimulation can be direct in the form of bodily contact, or indirect through the use of a tool or probe. direct and indirect send different types messages to the brain, but both provide information regarding roughness, hardness, stickiness, and warmth. the use of a probe elicits a response based on the vibrations in the instrument rather than direct environmental information. tactual perception gives information regarding cutaneous stimuli (pressure, vibration, and temperature), kinaesthetic stimuli (limb movement), and proprioceptive stimuli (position of the body). there are varying degrees of tactual sensitivity and thresholds, both between individuals and between different time periods in an individual's life. it has been observed that individuals have differing levels of tactile sensitivity between each hand. this may be due to callouses forming on the skin of the most used hand, creating a buffer between the stimulus and the receptor. alternately, the difference in sensitivity may be due to a difference in the cerebral functions or ability of the left and right hemisphere. tests have also shown that deaf children have a greater degree of tactile sensitivity than that of children with normal hearing ability, and that girls generally have a greater degree of sensitivity than that of boys. tactile information is often used as additional stimuli to resolve a sensory ambiguity. for example, a surface can be seen as rough, but this inference can only be proven through touching the material. when sensory information from each modality involved corresponds, the ambiguity is resolved. somatosensory information touch messages, in comparison to other sensory stimuli, have a large distance to travel to get to the brain. tactual perception is achieved through the response of mechanoreceptors in the skin that detect physical stimuli. the response from a mechanoreceptor detecting pressure can be experienced as a touch, discomfort, or pain, and the force of pressure is measured by a pressure algometer and a dolorimeter. mechanoreceptors are situated in highly vascularized skin, and appear in both glabrous and hairy skin. each mechanoreceptor is tuned to a different sensitivity, and will fire its action potential only when there is enough energy. the axons of these single tactile receptors will converge into a single nerve trunk, and the signal is then sent to the spinal cord where the message makes its way to the somatosensory systems in the brain. mechanoreceptors there are four types of mechanoreceptors: meissner corpuscles and merkel cell neurite complexes, located between the epidermis and dermis, and pacinian corpuscles and ruffini endings, located deep within the dermis and subcutaneous tissue. mechanoreceptors are classified in terms of their adaptation rate and the size of their receptive field. specific mechanoreceptors and their functions include: thermoreceptors that detect changes in skin temperature. kinesthetic receptors detect our movements and the position of our limbs. nociceptors that have bare nerve endings that detect tissue damage and give the sensation of pain. tests a common test used to measure the sensitivity of a person to tactile stimuli is measuring their two-point touch threshold. this is the smallest separation of two points at which two distinct points of contact can be sensed rather than one. different parts of the body have different degrees of tactile acuity, with extremities such as the fingers, face, and toes being the most sensitive. when two distinct points are perceived, it means that your brain receives two different signals. the differences of acuity for different parts of the body are the result of differences in the concentration of receptors. use in clinical psychology tactile stimulation is used in clinical psychology through the method of prompting. prompting is the use of a set of instructions designed to guide a participant through learning a behavior. a physical prompt involves stimulation in the form of physically guided behavior in the appropriate situation and environment. the physical stimulus perceived through prompting is similar to the physical stimulus that would be experienced in a real-world situation, and is makes the target behavior more likely in a real situation. smell modality sensation the sense of smell is called olfaction. all materials constantly shed molecules, which float into the nose or are sucked in through breathing. inside the nasal chambers is the neuroepithelium, a lining deep within the nostrils that contains the receptors responsible for detecting molecules that are small enough to smell. these receptor neurons then synapse at the olfactory cranial nerve (cn i), which sends the information to the olfactory bulbs in the brain for initial processing. the signal is then sent to the remaining olfactory cortex for more complex processing. odors an olfactory sensation is called an odor. for a molecule to trigger olfactory receptor neurons, it must have specific properties. the molecule must be: volatile (able to float through the air) small (less than 5.8 x 10-22 grams) hydrophobic (repellant to water) however, humans do not process the smell of various common molecules such as those present in the air. our olfactory ability can vary due to different conditions. for example, our olfactory detection thresholds can change due to molecules with differing lengths of carbon chains. a molecule with a longer carbon chain is easier to detect, and has a lower detection threshold. additionally, women generally have lower olfactory thresholds than men, and this effect is magnified during a woman's ovulatory period. people can sometimes experience a hallucination of smell, as in the case of phantosmia. interaction with other modalities olfaction interacts with other sensory modalities in significant ways. the strongest interaction is that of olfaction with taste. studies have shown that an odor coupled with a taste increases the perceived intensity of the taste, and that an absence of a corresponding smell decreases the perceived intensity of a taste. the olfactory stimulation can occur before or during the episode of taste stimulation. the dual perception of the stimulus produces an interaction that facilitates association of the experience through an additive neural response and memorization of the stimulus. this association can also be made between olfactory and tactile stimuli during the act of swallowing. in each case, temporal synchrony is important. tests a common psychophysical test of olfactory ability is the triangle test. in this test, the participant is given three odors to smell. of these three odors, two are the same and one is different, and the participant must choose which odor is the unique one. to test the sensitivity of olfaction, the staircase method is often used. in this method, the odor's concentration is increased until the participant is able to sense it, and subsequently decreased until the participant reports no sensation.