Week 3

• sensation

  the process of detecting environmental stimuli or stimuli arising from the body
• perception

  the process of interpreting sensory information
• stimulus

  anything that elicits a reaction from our sensory systems
• transduction

  the translation of incoming sensory information into neural signals
• attention

  a narrow focus of consciousness
• sensory adaptation

  the tendency to pay less attention to a nonchanging source of stimulation
• bottom-up processing


  perception based on building simple input into more complex perceptions
• top-down processing

  a perceptual process in which memory and other cognitive processes are required for interpreting incoming sensory information
• psychophysics

  the study of relationships between the physical qualities of stimuli and the subjective responses they produce
• absolute threshold

  the smallest amount of stimulus that can be detected
• difference threshold

  the smallest detectable difference between two stimuli
• signal detection

  the analysis of sensory and decision-making processes in the detection of faint, uncertain stimuli
• vision


  the sense that allows us to process reflected light
• visible light


  the energy within the electromagnetic spectrum to which our visual systems respond
• cornea

  clear surface at the front of the eye that begins the process of directing light to the retina
• pupil

  opening formed by the iris
• iris

  the brightly colored circular muscle surrounding the pupil of the eye
• lens

  the clear structure behind the pupil that bends light toward the retina
• retina

  layers of visual processing cells in the back of the eye
• fovea

  an area of the retina that is specialized for highly detailed vision
• rod


  a photoreceptor specialized to detect dim light
• cone

  a photoreceptor in the retina that processes color and fine detail
• optic nerve


  the nerve exiting the retina of the eye
• optic tracts


  nerve pathways traveling from the optic chiasm to the thalamus, hypothalamus, and midbrain
• analysis of visual input

  pathways from occipital cortex to adjacent temporal + parietal lobes
• parietal pathway


  helps us process movement in the visual environment
• temporal pathway

  responds to shape and color + contributes to our ability to recognize objects + faces
• trichromatic theory

  a theory of color vision based on the existence of different types of cones for the detection of short, medium, and long wavelengths
• opponent process theory


  a theory of color vision that suggests we have a red-green color channel and a blue-yellow color channel in which activation of one color in each pair inhibits the other color
• Gestalt psychologists


  the whole is something else other than the sum of its parts
• proximity

  objects that are close together tend to be grouped together
• continuity


  we assume points that form smooth lines when connected probably belong together
• closure

  people see a complete, unbroken image even when there are gaps in the lines forming the image
• simplicity

  we will use the simplest solution to a perpetual problem
• depth perception


  the ability to use the two-dimensional image projected on the retina to perceive three dimensions
• monocular cue


  a depth cue that requires the use of only one eye
• binocular cue


  a depth cue that requires the use of both eyes
• retinal disparity

  the difference between the images projected onto each eye

  • allows us to spot tiny variations in the depths of objects in the visual field
• astigmatism

  surface of the cornea is uneven
• audition

  the sense of hearing