Introduction to Perception Flashcards
what is sensation?
a passive process which brings external information into sensory systems.
what is perception?
an active process which is an interpretation of the sensations.
what did the visual cliff experiment find and what do the findings show?
most of the babies did not cross the cliff. this shows that once we start crawling (about 6.5 months) we have depth perception.
what did campos et al. add to the findings of the visual cliff experiment?
infants with more crawling experience did not cross the cliff.
what are the limitations of the visual cliff experiment?
depth perception starting at crawling can’t be a robust evolutionary concept, as 1/3rd of the babies did cross the cliff.
what are some features of perception?
intermodal, subjective.
why do we study perception?
it is an important process that affects human behaviour. it is how we understand the world around us and react accordingly.
what do Arcimbaldo’s fruit arrangements show?
we easily perceive objects that are in a facial configuration as faces.
explain the inversion effect.
it is harder to recognise faces when they are upside down. children with autism were not as susceptible to the inversion effect in a study looking at Arcimbaldo’s art.
what is the McGurk effect?
when we see someone saying a word (e.g ba ba ba) if their mouth movement changes, we hear what it looks like they’re saying (e.g far far far). visual system overrides auditory.
the visual system is:
always active. the perception of contourless figures reflect this.
what is top-down processing? give an example.
the identification of objects using existing knowledge. previous experience guides the processing of sensory information. e.g the muller-lyon illusion, the hollow mask.
what is bottom-up processing?
the representation of the object in view being gradually built up from what you can see.
what are the theoretical explanations of perception?
constructivism, gestalt theory, computational theory.
what is the Thatcher effect?
when a faces is inverted it looks normal and we recognise it as a face, but when it’s turned the right way round, the eyes and mouth are the wrong way round. this is top-down in nature as we use our previous experience of faces to identify an inverted face.
what does constructivism say about perception?
much of the visual information we take in is lost by the time it reaches the brain. we constantly use top-down processing to actively construct our own perception of reality. formation of incorrect hypotheses leads to errors of perception.
who formed the constructivism perception theory?
Gregory, 1970.
what is gestalt theory?
bottom-up.
we understand the world using sensory information we are provided with. we organise this information to make it understandable for us.
the whole is greater than the sum of the parts.
what is the law of proximity?
we favour grouping items that are close to each other together.
what is the law of similarity?
we group items that are similar together.
what is the law of closure?
when objects are grouped together we will naturally complete the contour lines and ‘close’ the image.
what is the law of continuity?
objects are grouped together if they are co-linear, or follow a direction. lines are seen as following the smoothest path.
what is the law of pragnanz?
reality is reduced to the simplest form possible.
what is the computational theory of perception?
used the stages of processing required for a computer to process a natural scene. the initial retinal image is the starting point of perception, bottom-up until the final stage of object description.
who formed the computational theory of perception?
Marr, 1982
what is the hollow mask illusion?
when looking in the inside of a rotating hollow mask, it looks like the nose is sticking out. even though it is concave. this is an example of top-down processing as our brains are not using to perceiving hollow faces.
