Language and Knowledge Flashcards
What is family resemblance? Who proposed it?
Wittgenstein proposed family resemblance - things in a particular category resemble one another in a number of ways.
What is the prototype approach to categorisation?
Membership is determined by comparing objects to a prototype that represents category (a typical member).
Rosch presented subjects with category title and 50 members of that category (i.e. birds). Subjects rated on a 1-7 scale based on how good an example the item was.
Rosch and Mervis- for items, subjects had to list as many attributes about them as possible. Items with a high interaction of the attributes showed a high family resemblance.
Smith and co - used sentence verification technique - subjects had to determine is a sentence is true or not and then answer yes or no (i.e. is an apple a fruit or is a pomegranate a fruit). Subjects answered faster for prototypical objects - called the typicality effect.
Subjects listed prototypical items first when creating a list of members in the category.
Rosch - subjects heard a prime (i.e. green) and then 2 seconds later, were presented with 2 colours side-by-side. Had to indicate if the colours were the same or different. Subjects were presented with either same colour (prime colour - good example); same colour (dull - poor example); different colours. Subjects responded faster for good example of same colour. Rosch theorised that when subjects heard green, they imagined a prototypical green, and hence seeing it resulted in faster recognition.
What is the exemplar approach to categorisation?
Exemplar approach is when actual members of the category are encountered in the past to form the persons understanding of the category. Rosch’s experiments can be explained by the exemplar approach, as most exemplars are prototypical.
What is the better approach to categorisation?
The exemplar approach. It can more easily take into account atypical cases.
However, some research says that small categories may work best for exemplars (i.e. US presidents) and larger categories using the prototype approach (i.e. birds).
What was Rosch’s approach to categorisation?
Rosch proposed the heirarchial level of categories. There were different levels of categories:
Superordinate or Global (Furniture)
Basic (Chair/table/bed)
Subordinate (Kitchen;dining/kitchen;dining/single;double)
Rosch got participants to do the family resemblance task. Subjects listed 3 categories on average for superordinate, 9 for basic and 10.3 for subordinate.
Rosch found that subjects generally labeled things by their basic title, unless they were an expert, and then they might label it as subordinate.
Tanaka and Taylor - asked students to walk around campus and label things - found that subjects generally labelled things by basic level, expect experts who labelled them by subordinate. Learning affects categorisation.
Describe the semantic network approach
The semantic network approach was introduced by Collin and Quillian. It says that nodes are connected by links in a hierarchical model. The nodes have properties at them that are common to the node (i.e. bird might have property can fly). Properties are located as high as possible to common nodes. Sharing properties relates to cognitive economy. Exceptions to property rules may be added at lower levels (i.e. ostrich can’t fly but is a bird).
Collins and Quillian tested model by using sentence verification technique. Found subjects answered slower when distance between nodes was greater (i.e. canary is a bird vs canary is a mammal).
What is spreading activation?
Spreading activation is when activity spreads out along links connected to activated node. At node bird, canary and ostrich are primed so that they can be retrieved more easily.
Meyer and Schraneveldt - lexical decision task - subjects read stimuli (word-pair) - words or not words and have to indicate if word or not. Push no if one of the word pair is not a word. A close association with the word pair resulted in a faster response time, due to spreading activation.
What are some criticisms of the Collins and Quillian model?
The theory doesn’t explain the typicality effect (i.e. faster response time for items that are typical of a category).
Issues with cognitive economy - i.e. faster response time for animal than mammal.
What is the connectionist approach?
McClelland and Rumelhart. AKA parallel distributed processing (PDP).
Circles are units, lines are connections that transfers info between units, input units send signals to hidden units which sends signals to output units, connection weights determine strength of signal.
McClelland and Rogers - more complex model.
Connectionist model indicates category, the relationship and the various attributes. Concept, such as canary, is represented by pattern of activity in the units in the network.
The network needs to be trained in order for results to occur. Weights need to be adjusted - occurs through learning process. Error responses in property unit cause an error signal to be sent back (back propagation). Errors result in a change and a new activation pattern.
McClelland and Rogers created a programme for computer activation and found that the patterns change over time.
What is the sensory-functional hypothesis?
Warrington and Shallice - found that some people had category-specific memory impairment (unable to identify one type of object but could identify others). This was caused by encephalitis. Patients were unable to identify animals but could identify nonanimals. Warrington and Shallice hypothesised that differentiation of living things requires sense.
Proposed sensory-functional hypothesis - ability to differentiate living things and artifacts depends on semantic memory system that distinguishes sensory attributes and a system that attributes function.
What is the semantic category approach?
Specific neural circuits for some specific categories. Mahon and Caramazza - limited number of categories innately determined because of importance for survival.
What is the multiple-factor approach?
Searching for factors that determine how concepts are divided up within a category.
Hoffman and Ralph - subjects rated on a 1-7 scale based on features such as colour, taste, smell. Found that artifacts and animals were different, however overlap in machines which can move.
Proposed crowding - animals tend to share properties (i.e. eyes, legs). Artifacts share fewer properties.
What is the embodied approach?
Emobided approach - knowledge of concepts is based on reactivation of sensory and motor processes that occur when we interact with the object (i.e. when we see a hammer, sensory and motion areas activated as well as areas involved in the motion of it).
Gallese and co - watched a monkey grabbing food and then researcher grabbing food. Discovered mirror neurons - cause activation of areas associated with movement when we see someone doing something.
Semantic somatotopy - correspondence between words related to specific parts of the body and location of brain activity.
Garcea and co - patient AA. Unable to perform action associated with object but able to identify objects - concluded ability to represent motor activity is not necessary for recognising objects - as embodied approach would predict.
Problem with this approach is the difficulty to explain concepts such as truth.
What is the definitional approach to categorisation?
Decide if something is a member of a category based on if the object meets the definition.
What is language?
Language is a system of communication using sounds or symbols that enables us to express our thoughts, feelings, ideas and experiences.
It is hierarchical - series of small components that can be combined to make larger units.
It is governed by rules - components must be arranged in certain ways.
