Chapter 3 Flashcards
perception
conscious experiences as a result of sensory stimulation/information
two types of information used by human perceptual systems
- environmental energy stimulating receptors
- knowledge and expectations that the observer brings to the situation
template-matching theory
- early theory of recognition
- suggest a template of every object in our environment is thought to be stored in our memory
- presentation of visual stimulus is compared with templates stored in memory
problems with template-matching theory
- does not explain why we recognize objects that do not match a template in our memory exactly
- the way we see objects is highly variable
- requires a huge number of templates even for a single type of object - this would mean we have an infinite number of templates learned and stored in memory (unlikely)
feature detection theory
- objects can be decomposed into parts (features)
- e.g. the letter “A” - it has 2 diagonal lines and a horizontal line
- the features are matched to the features of objects in memory this will result in recognition
Neissers study of perception
- recognition involves feature detection there should be perceptual confusions - that is impaired recognition of objects that share overlapping features (e.g. angular features)
- the results slower to detect Z among items with similar features (list 2: angular features) compared to dissimilar features (list 1 - curved features)
problems with feature detection
- does not take spatial relationships into account
- detecting individual features can be inadequate for recognizing some patterns
biedermans recognition by components model (1987)
- structural theories focus on how features are combined (recognition by components)
- involves features and the arrangement of features
- all objects are constructed from a small number of 3 dimensional shapes referred to as GEONS
problems with recognition by components model
- relying on features and how they combine us not enough to explain how we can distinguish specific members of a category
- e.g. a granny smother apple vs. a gala apple
helmholtz theory of unconscious inference
- had a realization that the image on the retina is ambiguous
- the process of perceiving what is most likely to have caused the pattern on the retina happens rapidly and unconsciously.
likelihood principle
- states that we perceive the object that is most likely to have caused the pattern of stimuli we have receive
- the unconscious assumptions are based on this principle
unconscious inference
idea that some of our perceptions are the result of unconscious assumptions that we make about the environment
gestalt principle of organization
- had the idea that perceptions could not be explained by adding up small sensations
- proposed the “principles of perceptual organization” to explain the way elements are grouped together to create larger objects
3 principles of of perceptual organization
- the principle of good continuation
- pragnanz/principle of good figure or simplicity
- the principle of similarity
the principle of good continuation
- when points are connected, and result in straight or smoothly curving lines are seen as belonging together
- lines tend to be seen as the smoothest path
- objects that are overlapped by other objects are perceived as continuing behind the overlapping object
pragnanz/principle of good figure or simplicity
- states that every stimulus pattern is seen in such a way that the resulting structure is as simple as possible
- e.g. olympic circles (seen as 5 circles and not a larger number of more complicated shapes
the principle of similarity
states that similar things appear to be grouped together
regularities of the environment
- defined as characteristics of the environment that occur frequently
- e.g. blue is associated with the sky, landscapes are associated with green
2 types of regularities
- physical regularities
- semantic regularities
physical regularities
- regularly occurring physical properties of the environment
There are more vertical and horizontal orientations in the environment - seen in both human-made and natural environments
oblique effect
- finding that vertical and horizontal orientations can be perceived more easily than other (slanted) orientations
- more neurons respond to horizontals and vertical than to oblique orientations
light-from-above-assumption
- the assumption that light is coming from above
- this is a heuristic that can influence how we perceive three-dimensional objects that are illuminated.
semantic regularities
- characteristics associated with the functions carried out in different types of scenes
- e.g. food preparation, cooking, and perhaps eating occur in a kitchen
scene schema
a persons knowledge about what is likely to be contained in a particular scene
bayesian inference - thomas bayes
- proposed that our estimate of the probability of an outcome is determined by two factors:
1. prior probability
2. the extent to which the available evidence is consistent with the outcome
comparing the 4 approaches of perception
- The approaches of Helmholtz, regularities, and Bayes all have in common the idea that we use data about the environment, gathered through our past experiences in perceiving, to determine what is out there (top-down processing)
- in contrast, Gestalt psychologists emphasized the idea that the principles of organization are built in
top-down processing
- processing that involves perceiving things based on your prior experiences and knowledge
- you use what you already know to make sense of the new information you encounter
- also called knowledge-based processing
bottom-up processing
- processing that starts with information received by the receptors
- also called data-based processing
- enables people to rapidly identify objects and scenes
speech segmentation
- the ability to discriminate words in conversation based on:
- context/sentence use/meaning/top-down processing
- meaning of the word
- knowledge of word structure to assess transitional probabilities
transitional probabilities
likelihood that one sound follows another sound (based on our knowledge of that language
statistical learning
- the process of learning about transitional probabilities and about other characteristics of language
- also occurs for vision, based on learning about what types of things usually occur in the environment
- infants as young as 8mo of age are capable of statistical learning
inverse projection problem
- task of determining the object that caused a particular image on the retina
- it involves starting with the retinal image and extending rays out from the eye
viewpoint invariance
the ability to recognize an object seen from different viewpoints
purpose of perception
- create our awareness of what is happening in the environment, as when we see objects in scenes or we perceive words in a conversation
- enable us to interact with the environment
two process streams of the brain
- on involved with perceiving objects
- the other involved with locating and taking action toward these objects
2 physiological research methods
- brain ablation
- neuropsychology
brain ablation
the study of removing parts of the brain in animals, usually done to determine the function of this area by assessing the effect on the animal’s behavior
neuropsychology
the study of the behaviour of people with brain damage
2 tasks completed after a brain ablation
- object discrimination problem
- landmark discrimination problem
object discrimination problem
- the task is to remember an object based on its shape and choose it when presented with another object after a delay
- found to be difficult after the temporal lobes were removed
- associated with research on the ‘what’ processing stream
landmark discrimination problem
- the task is to remember an object’s location and to choose that location after a delay
- found to be difficult after the parietal lobes were removed
- associated with research on the ‘where’ processing stream
‘what’ pathway
- the neural pathway, extending from the occipital lobe to the temporal lobe, that is associated with perceiving or recognizing objects
- corresponds to the perception pathway
- aka the Ventral Pathway
‘where’ pathway
- the neural pathway, extending from the occipital lobe to the parietal lobe, that is associated with neural processing that occurs when people locate objects in space
- roughly corresponds to the action pathway
- aka the Dorsal Pathway
executive attention network
extremely complex and may involve two separate networks and is responsible for executive functions
executive functions
- include a range of processes that involve controlling attention and dealing with conflicting responses
- e.g. stroop test
effective connectivity
- how easily activity can travel along a particular pathway between two structures
- effectivity between different structure in a network changed depending on conditions
synchronization
- occurs when neural responses become synchronized in time
- a mechanism responsible for enhanced effective connectivity and enhanced communication between two areas that accompany shifts of attention
3 mechanisms involved in dealing with conflicting stimuli
- cognitive control
- inhibitory control
- willpower
mirror neurons
- in the premotor cortex
- originally found in monkeys
- neurons in the premotor cortex, originally discovered in the monkey, respond both when a monkey observes someone else (usually the experimenter) carrying out an action and when the monkey itself carries out the action
mirror neuron system
- a network of neurons in the human brain that have mirror neuron properties
- involved with understanding the intentions behind actions
- found using fMRI
purpose of mirror neurons
- involved in determining the goal or intention behind an action
- also involved in responding to the sequence of actions that is most likely to follow