psych unit3

Sensation

Feeling/perception coming from the body

Perception

Brains process of interpreting sensory information

Signal detection theory

theory predicting how and when we detect the presence of a faint stimulus amid background stimulation.  Assumes there is no single absolute threshold.

Sensory adaptation

Respond to changes better than constant stimuli

Perceptual constancy

perceiving objects as unchanging (having consistent shapes, size, lightness, and color) even as illumination and retinal images change

Difference threshold

Noticeable difference

Webers law

The greater the stimulus, the greater the change necessary to notice a difference

Gestalt principles

Figure ground, proximity, similarity, closure, continuity, etc.

Depth perception

1. the ability to see objects in three dimensions although the images that strike the retina are two dimensional; allows us to judge distance

Absolute threshold

1. minimum stimulus required to activate our senses at least 50% of the time

Visual cliff

1. a laboratory device for testing depth perception in infants and young animals

   1. See example:  hasn’t quite held up.  Infants refused to crawl on the glass because it looked like a drop.  Newborn animals tended to respond the same way despite no walking experience

   2. More recent tests have shown the depth perception in these situations may be learned as first time visual cliff participants often crawl (or later walk) right over the edge.  Later they perceive the drop and respond accordingly

Binocular cues

1. depth cues, such as retinal disparity, that depend on the use of two eyes

Monocular views

cues for perceiving depth that only require one eye: linear perspective, relative size, overlap, shading

Phi phenomenon

1. an illusion of movement created when two or more adjacent lights blink on and off in quick succession  (remember the purple circles flashing on and off on Brain Games and you saw a green circle moving around?  The green circle was never there)

Retinal disparity

1. binocular cue for perceiving depth:  By comparing images from the retinas in the two eyes, the brain computes distance – the greater the disparity (difference) between the two images, the closer the object

Top-down processing

1. Analysis that emphasizes the perceiver’s expectations, concept memoires and other cognitive factors, rather than individual characteristics.  Basically, you see what you are looking for

Bottom-up processing

1. analysis that emphasizes the characteristics of the stimuli rather than our concepts and expectations

Contributions of Gustav Fechner

1. absolute threshold.  1860.  lowest level of stimulation that a person can consciously detect 50% of the time the stimulation is present.  

Contributions of David Hubel

1. Hermann Grid example.  Why do we see gray blogs or diamonds?  One explanation for this illusion is attributed to the responses of neurons in the primary visual cortex that respond best to bar light of a specific orientation.  Such neurons are called “simple cells” and were first discovered by David Hubel and Torsten Wiesel.  They also discovered other cells including “complex cells,”  which respond to orientation and movement, and “end-stopped cells,” which respond best to corners, curvature, or sudden edges.  Collectively these cells have been referred to as feature detectors because they respond to specific features of a stimulus.  

Context effects

1. Context and situation matter.  We can be primed or cued to perceive things through suggestion both overt and subliminally 

Perceptual set

1. mental predisposition to perceive one thing and not another.  Perception meets expectation

Sensation

Feeling/perception coming from the body

Perception

Brains process of interpreting sensory information

Signal detection theory

theory predicting how and when we detect the presence of a faint stimulus amid background stimulation. Assumes there is no single absolute threshold.

Sensory adaptation

Respond to changes better than constant stimuli

Perceptual constancy

perceiving objects as unchanging (having consistent shapes, size, lightness, and color) even as illumination and retinal images change

Difference threshold

Noticeable difference

Webers law

The greater the stimulus, the greater the change necessary to notice a difference

Gestalt principles

Figure ground, proximity, similarity, closure, continuity, etc.

Depth perception

1. the ability to see objects in three dimensions although the images that strike the retina are two dimensional; allows us to judge distance

Absolute threshold

1. minimum stimulus required to activate our senses at least 50% of the time

Visual cliff

1. a laboratory device for testing depth perception in infants and young animals 1. See example: hasn’t quite held up. Infants refused to crawl on the glass because it looked like a drop. Newborn animals tended to respond the same way despite no walking experience 2. More recent tests have shown the depth perception in these situations may be learned as first time visual cliff participants often crawl (or later walk) right over the edge. Later they perceive the drop and respond accordingly

Binocular cues

1. depth cues, such as retinal disparity, that depend on the use of two eyes

Monocular views

cues for perceiving depth that only require one eye: linear perspective, relative size, overlap, shading

Phi phenomenon

1. an illusion of movement created when two or more adjacent lights blink on and off in quick succession (remember the purple circles flashing on and off on Brain Games and you saw a green circle moving around? The green circle was never there)

Retinal disparity

1. binocular cue for perceiving depth: By comparing images from the retinas in the two eyes, the brain computes distance – the greater the disparity (difference) between the two images, the closer the object

Top-down processing

1. Analysis that emphasizes the perceiver’s expectations, concept memoires and other cognitive factors, rather than individual characteristics. Basically, you see what you are looking for

Bottom-up processing

1. analysis that emphasizes the characteristics of the stimuli rather than our concepts and expectations

Contributions of Gustav Fechner

1. absolute threshold. 1860. lowest level of stimulation that a person can consciously detect 50% of the time the stimulation is present.

Contributions of David Hubel

1. Hermann Grid example. Why do we see gray blogs or diamonds? One explanation for this illusion is attributed to the responses of neurons in the primary visual cortex that respond best to bar light of a specific orientation. Such neurons are called “simple cells” and were first discovered by David Hubel and Torsten Wiesel. They also discovered other cells including “complex cells,” which respond to orientation and movement, and “end-stopped cells,” which respond best to corners, curvature, or sudden edges. Collectively these cells have been referred to as feature detectors because they respond to specific features of a stimulus.

Context effects

1. Context and situation matter. We can be primed or cued to perceive things through suggestion both overt and subliminally

Perceptual set

1. mental predisposition to perceive one thing and not another. Perception meets expectation