Sensation and Perception

is the process that detects stimuli from our body and our environment

is the process that organizes sensations into meaningful objects and events

Determining relevance of stimulation

Telling identity of an object, even when appearance is distorted

Keeping the appearance / size of objects constant, even though their retinal images are changing

Cannot process all impinging stimulation

quick search

brief periods (300 msec) during which the eyes are relatively stationary and visual information is acquired from the environment

quick jumps of the eye from one place to the next (20 msec) during which vision is essentially suppressed

attention can move within a modality, such as from one visual stimulus to another, or between modalities, from seeing to listening

Hearing your own name mentioned across a room crowded with conversation

repeating back one auditory message (we consciously remember little, if anything, about nonattended information)

different auditory message received by each ear

the object of interest which appears more solid than the ground and appears in front of it

the region that appears to be behind the figure

if the vertical distance between two dots is reduced, columns will most likely be seen

grouping like objects with like objects

different kinds of visual information that, logically or mathematically, provide information about some object’s depth

Eyes have slightly different views of same object

If view contains similar objects that differ in size, smaller objects seen as further away

If one object obstructs view of another, the overlapping object is seen as closer

Among similar objects, those located closer to the horizon are perceived as further away

Parallel lines seen as converging in the distance are perceived as vanishing in the distance (ASH)

Relative size of shadows perceived as related to height / size of object

Speed at which objects appear to move affects perceived distance

Rapid flashing of still images in which actors’ expressions change subtly from one image to the next

Movement of object through all intermediate locations in space

Selective loss in sensitivity to motion (downward moving stripes), but not to motion that differs significantly in direction or speed

Incorrectly combining two separate features of an object

primitive features (e.g., shape and color) are perceived (visual search task)

Individual, primitive features are combined to form an integrated whole

malleable, task responsive perceptual system

Cells in visual cortex that respond to only specific stimuli the receptive field (RF= part of retinal region)

Respond only to simple line stimuli at a particular orientation and position with the receptive field

Respond to bar or edge in a particular orientation, but stimulus can be anywhere in visual field

Stimulus must be in particular orientation but also must be a specific length

Features are combined through network in memory that allows identification

driven solely by input, raw, sensory data

driven by a person’s knowledge

objects that can be perceived in more than one way

breakdowns or disorders in recognition

difficulty recognizing visually presented objects due to damage in temporal lobe regions of the cortex

category-specific deficits as a result of damage to the right hemisphere

inability to recognize words as a result of damage to the left occipital lobe

The process of reducing the information that comes in from the physical world through our senses to a more manageable set of categories

The brain’s ability to maintain the perception of the underlying physical characteristics of an object, even when the sensory manifestations of the objects change drastically