SENSATION AND PERCEPTION

KEY POINTS Distinguish between sensation and perception Psychophysics: absolute threshold and difference threshold Identify each major sensory system, their receptors, and type of sensory information each receives Perception: selection, organization and interpretation

Sensation Input of sensory information Process of receiving, converting, and transmitting information from the outside world

Sensory Systems Vision Hearing Smell (olfaction) Taste (gustation) Vestibular sense (balance) Kinethesis (body movement) Touch (pressure, pain, temperature)

Vision Visual receptor cells located on retina:rods for night vision and cones for color vision The eye captures light and focuses it on the visual receptors, which convert light energy to neural impulses sent to the brain

Hearing Audition (hearing) occurs via sound waves, which result from rapid changes in air pressure caused by vibrating objects Receptors located in the inner ear (cochlea) tiny hair cells that convert sound energy to neural impulses sent along to brain

Smell and Taste Olfaction (smell) receptors are located at top of nasal cavity Gustation - (taste) receptors are taste buds on tongue. Four basic tastes: sweet, salty, sour and bitter

Body Senses Vestibular sense (sense of balance) results from receptors in inner ear Kinethesis - (body posture, orientation, and body movement) results from receptors in muscles, joint and tendons Skin senses detect touch (pressure, temperature and pain)

Processing Sensory reduction - filtering and analyzing of sensations before messages are sent to the brain Transduction - process of converting receptor energy into neural impulses the brain can understand Adaptation- decreased sensory response to continuous stimuli

Psychophysics Study of the relationship between the physical properties of stimuli and a person’s experience of them Absolute threshold - minimum amount of energy we can detect Difference threshold - (jnd) the smallest change in a stimulus we can detect

Perception “…a constructive process by which we go beyond the stimuli that are presented to us and attempt to construct a meaningful situation”.

Perceptual Processing Top-down: perception is guided by higher-level knowledge, experience, expectations, and motivations Bottom-up: perception that consists of recognizing and processing information about the individual components of the stimuli

Perception-Key Concepts 1.Selection 2.Organization 3.Interpretation 4.Subliminal perception and ESP

1. Three Major Factors of Selection Selective attention Feature detectors Habituation

2. Organization Form (Gestalt) Constancy(size, shape, color, brightness) Depth Color

Gestalt Principles Rules that summarize how we tend to organize bits and pieces of information into meaningful wholes

Gestalt Psychology: Form figure ground proximity closure contiguity similarity

Constancy Size constancy Shape constancy Color constancy Brightness constancy

3. Four Major Factors of Interpretation Perceptual adaptation Perceptual set Individual motivation Frame of reference

Subliminal Perception Stimuli that occur below the threshold of our conscious awareness but have a weak, if any effect on behavior

4. Extrasensory Perception (ESP) Alleged perception in the absence of sensory data Types of ESP - telepathy, precognition, clairvoyance, and psychokinesis