BRS 214 Introduction to Psychology Sensation & Perception Ms. Dawn Stewart BSC, MPA, PHD

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

Sensation & Perception Sensation: Sensation: stimulation of sensory receptors. stimulation of sensory receptors. transmission of sensory information to the brain. transmission of sensory information to the brain. Perception: Perception: Process by which sensations are organized and interpreted, forming an inner representation of the world. Process by which sensations are organized and interpreted, forming an inner representation of the world.

Sensation and Perception Sensation occurs: Sensation occurs: a) Sensory organs absorb energy from a physical stimulus in the environment. a) Sensory receptors convert this energy into neural impulses and send them to the brain.

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

Sensation and Perception Sensations can be defined as the passive process of bringing information from the outside world into the body and to the brain. Sensation refers to the process of sensing our environment through touch, taste, sight, sound, and smell. The process is passive in the sense that we do not have to be consciously engaging in a "sensing" process.

Sensation and Perception Perception can be defined as the active process of selecting, organizing, and interpreting the information brought to the brain by the senses Perception is the way we interpret these sensations and therefore make sense of everything around us.

Sensation and Perception Perception can be defined as the active process of selecting, organizing, and interpreting the information brought to the brain by the senses Perception is the way we interpret these sensations and therefore make sense of everything around us. Perception is the way we interpret these sensations and therefore make sense of everything around us.

Sensation and Perception Perception follows: Perception follows: a) The brain organizes the information and translates it into something meaningful.

Vision Visual receptor cells located on retina:rods for night vision and cones for color 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 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 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 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 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 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 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 Kinethesis - (body posture, orientation, and body movement) results from receptors in muscles, joint and tendons Skin senses detect touch (pressure, temperature and pain) Skin senses detect touch (pressure, temperature and pain)

Processing Sensory reduction - filtering and analyzing of sensations before messages are sent to the brain 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 Transduction - process of converting receptor energy into neural impulses the brain can understand Adaptation- decreased sensory response to continuous stimuli 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 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 Absolute threshold - minimum amount of energy we can detect Difference threshold - (jnd) the smallest change in a stimulus 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”. “…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 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 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 Selective attention Feature detectors Feature detectors Habituation Habituation

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

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

Gestalt Psychology: Form figure ground figure ground proximity proximity closure closure contiguity contiguity similarity similarity

Constancy Size constancy Size constancy Shape constancy Shape constancy Color constancy Color constancy Brightness constancy Brightness constancy

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

Subliminal Perception Stimuli that occur below the threshold of our conscious awareness but have a weak, if any effect on behavior 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 Alleged perception in the absence of sensory data Types of ESP - telepathy, precognition, clairvoyance, and psychokinesis Types of ESP - telepathy, precognition, clairvoyance, and psychokinesis