L3: Perception Flashcards
What is perception?
Experience resulting from stimulation of the senses.
A complex set of processes by which we organise, recognise and make sense of the sensations we receive from environmental stimuli.
What are the two types of information the perceptual system uses?
- Environmental energy stimulating the receptors.
- Knowledge and expectations the observer brings to the situation
Is human perception special?
Unlike humans, most mammals, many birds, and insects, and fish can see ultraviolet light, goldfish see ultraviolet +
infrared, snakes can see temperature
What is the inverse projection problem?
The task of determining the object
responsible for a particular image on
the retina.
Involves starting with the retinal image,
then extending outward to the source
of that image.
What is meant by direct perception theories?
Bottom-up processing
Perception comes from stimuli in the environment
Parts are identified and put together, and then recognition occurs/
What is meant by constructive perception theories?
Top-down processing
Processing originates in the brain, “top” of the perceptual system.
People actively construct perceptions
Is the perception of pain top-down or bottom-up?
Bottom-up: It depends on the stimulation of the receptors. Pain occurs when receptors in the skin are stimulated.
Pain is influenced by what a person expects, how the person directs their attention and the distracting stimuli present.
What is speech segmentation?
Ability to tell when one word ends and another begins
What is meant by transitional probalities?
Knowing which sound will likely follow another in a word.
What are gestalt principles?
The mind groups patterns according to intrinsic laws of perceptual organization based on knowledge about the world.
What is Helmholtz’s unconscious inference?
Top-down theory to address visual ambiguity
Some perceptions are the results of unconscious assumptions we
make about the environment
– We use our knowledge to inform our perceptions.
We infer much of what we know about the world
Likelihood principle:
– We perceive the world in the way that is “most likely” based on
our past experiences.
What is the figure ground principle?
There needs to be a distinction between an object and it’s background
What is the principle of good continuation?
Lines tend to be seen as following the smoothest path.
Good continuation helps us perceive the rope as a single strand.
What is the law of pragnanz?
Principle of simplicity or good figure
Every stimulus pattern is seen so the resulting structure is as simple as possible.
What is meant by the bayesian inference?
Two factors influence one’s estimate of the probability of a given outcome:
- the prior probability
- the likelihood of a given outcome
