PSY105: Sensation and Perception

sensation

the process by which our sensory receptors (like eyes) and nervous system receive and represent stimulus energies from our environment and convert them into neural signals

sensory adaptation

diminished sensitivity as a consequence of constant stimulation

perception

the process of organizing and interpreting sensory information, enabling us to recognize meaningful objects and events

bottom-up processing

breaking a sensory into its component parts and then making sense of those parts

top-down processing

the idea that we start with information about what we might expect and fill it in

transduction

reactive sensory stimulation through specialized receptor cells that transform that stimulation into neural impulses and then deliver that neural information to the brain

absolute threshold

the minimum energy needed to detect a stimulus 50% of the time

signal detection theory

predicts how we detect signal from the noise

subliminal threshold

stimuli below the absolute threshold

difference threshold (Weber’s Law)

the minimum difference between two stimuli needed for detection 50% of the time

perceptual sets

our expectations and mental tendencies that can cloud our perceptions

context

perceptions of stimuli can be affected by other things going on

emotions

can impact our perception, especially when used as a tool for priming (sad songs make us hear sad words)

gestalt

clusters of sensations organized to form meaningful perceptions from sensory information

figure-ground perception

organization of the visual field into objects (figures) that stand out from their surroundings (ground)

grouping

our perceptions need to organize the figure into a meaningful form using grouping rules like proximity, continuity, similarity, closure, and connectedness

depth perception

the ability to see things in 3 dimensions, which enables us to judge distances

binocular clues

depth cues that depend on the use of two eyes

retinal disparity

the images from the two eyes differ

monocular clues

depth cues that are available to either eye

relative size

if two objects are similar in size, we perceive the one that casts a smaller retinal image to be farther away

interposition

objects that block other objects tend to be perceived as closer

relative height

we perceive objects that are higher in our field of vision to be farther away than those that are lower

texture

more detail in texture is perceived as being closer

how the eye works

light from the candle passes through the cornea and the pupil and gets focused and inverted by the lens. The light then lands on the retina, which triggers a photochemical process which results in neural impulses being sent out through the optic nerve

lens accommodation

the lens change shape to focus on near or far objects