Perception Flashcards
perception
the process of interpreting and understanding sensory information
perception occurs in conjunction with _____
action
a problem with current computer programs designed to detect objects
they make certain mistakes that humans would never make
Information processing model
input -> sensory memory -> STM -> LTM
sensation
the first contact with the stimulus, which is transformed from light, sound, etc. into a neural impulse which is passed to the brain
Where are the photoreceptors located?
the retina
The types of photoreceptors and their purpose
- cones are colour sensitive (red, green, blue)
- rods are luminance sensitive (black, white)
cones are mainly clustered in the
fovea (foveal pit)
where are rods located?
in an increasing concentration coming away from the fovea
the blind spot is where
the information leaves the eye to go to the brain
how information gets passed from photoreceptors to the brain
photoreceptors -> bipolar cells -> ganglion cells -> visual cortex
saccade
the quick movement (25-175 msec) of the eyes from one location to another
fixation
the brief period (~200 msec) when the eyes stop moving and process the visual scene
perceptual span
the number of items that an individual can report form a brief display that did not allow for eye movements (~4.5 items)
George Sperling
introduced the concept of iconic memory (1960)
Sperling’s experiment
- replicated perceptual span studies and found similar results
- introduced partial report (just 1 row), which gave much better results
Sperling’s subjects reported that:
- they saw the whole array of images but forgot it while reporting
- the array seemed to fade but was available to examine mentally even after it went off-screen
Averbach & Coriell
- replicated Sperling’s study but only asked them to report a single item by putting a bar underneath where the item was
- their performance was more accurate than when asked for a row
- when a circle was used instead of a bar, performance was worse
Sperling found that information in the iconic store is ___
very visual and quite unprocessed as to meaning (raw, sensory information)
the duration of information in the sensory store lasts for
- 1/4 to 1 second (iconic)
- 1 to 4 seconds (echoic)
information transfers from sensory memory to working memory through
pattern recognition
template theory
the mind uses templates, a pattern treated as an unanalyzed whole, to recognize whether a stimulus matches it
challenges to template theory
- a stimulus can be interpreted differently depending on the context
- we can still recognize a stimulus when partially blocked out, in a different orientation, etc.
feature theory
a pattern is decomposed into different elements (features) in order to recognize a stimulus
bottom-up
processsing begins with the sensory input and ends with its representation, therefore the outcome of a lower step is never affected by a higher step in the process
top-down
the output of a lower step is influenced by a higher one (knowledge, context), changing the way we process a stimulus
direct perception theories
- bottom-up
- perception comes only from stimuli in the environment
- parts are identified and put together, then recognition occurs
constructive perceptive theories
- top-down processing
- people actively construct perceptions using information based on knowledge and expectations
Gestalt Principles of Perceptual Organization
rules governing how features should be put together (rule of similarity, continuation, etc.)
Law of Pragnanz
every stimulus pattern is seen so the resulting structure is simple as possible
unconscious inference
our perceptions are the result of unconscious assumptions that we make about the environment
likelihood principle
we perceive the world in the way that is “most likely” based on our past experiences
oblique effect
we perceive vertical/horizontals more easily than other orientation because we experience them more regularly
light-from-above assumption
we assume light comes from above because this is common in our environment
scene schema
knowledge of what a given scene ordinarily contains
Bayesian inference
we estimate the probability of an outcome is influenced by:
- the prior probability
- the likelihood of a given outcome
movement adds ____ to perception but also creates more ____ perceptions
- complexity
- accurate
inverse projection problem
there is an infinite number of sources for any given retinal image
viewpoint invariance
the ability to recognize an object seen from different viewpoints
speech segmentation
being able to tell when one word ends and the next one begins
Gestalt psychology
rejected the idea that perception is formed by adding up of sensations, believed that the whole is different from the sum of its parts
apparent movement
when movement is perceived even though nothing is actually moving
physical regularities
regularly occurring physical properties of the environment
semantic regularities
the characteristics associated with the functions carried out in different types of scenes
experience-dependant plasticity
the structure of the brain is changed by experience
what (perception) pathway
leads to the temporal lobe, responsible for determining an object’s identity
where (action) pathway
leads to the parietal lobe, responsible for determining an object’s location
