BRS 214Introduction to

PsychologySensation & Perception

2013-2014

Ms. Dawn Stewart BSC, MPA, PHD

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 & Perception

Sensation: stimulation of sensory receptors. transmission of sensory

information to the brain.

Perception: Process by which sensations are

organized and interpreted, forming an inner representation of the world.

Sensation and Perception

Sensation occurs:a) Sensory organs absorb energy from a

physical stimulus in the environment.

b) Sensory receptors convert this energy into neural impulses and send them to the brain.

Sensory Systems

Vision Hearing Smell (olfaction) Taste (gustation) Vestibular sense (balance) Kinethesis (body movement) 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. 

Sensation and Perception

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

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