L6 Concepts and Thought

• What is the classical view?

  Concepts can be defined by an exhaustive list of necessary and sufficient semantic features. Example: 'cat' = catches mice, has whiskers, purrs
• Issues with the classical view?


  Very difficult to come up with an exhaustive list of features for a given concept. It is hard to find features which every instance of the concept includes for example not every bird flies and lives in a tree.
• What is family resemblance?

  Some concepts apply by virtue of a ‘family resemblance’, rather than a set of necessary and sufficient properties. A family resemblance concept has an open-ended set of identifying features, such that not all the features need be instantiated for the concept to apply. 
• Typicality: people are quicker at verification tasks when the item is typical to a category e.g. robin is a bird over tomato is a fruit
• Prototype theory: When we make a category instance on a new instance, we compare it to a mental representation of a prototype.
• What is exemplar theory?

  We do not compare the new instance to a prototype. Instead we compare it with stored instances of all other members of the category.
• What is some evidence for category-specific deficits?

  Warrington & McCarthy: patient had normal knowledge of living things, but was selectively impaired on human-made objects.

  Warrington & Shallice: patient had intact knowledge about human-made objects but impaired insight into living things
• What are the categories of category-specific deficits?

  Animate objects, inanimate biological objects, and artefacts
• What is a homo economicus?

  An imagined person which has an infinite ability to make rational decisions.
• What are heuristics?

  Mental shortcuts, which are often effective and fast when having to make a decision, but are often wrong, leading to biases, and violating rationality - a 'thinking error'.
• What is availability bias?

  A probability estimate of occurence is judged by its availability in memory.
• Availability bias:

  For low probability but high-risk events, we tend to use availability bias rather than trying to compute 'objective' risk - e.g. plane crashes
• What is conjunction fallacy?

  People tend to believe that two events are more likely to occur together than either individual event, even though the combined probability of two events is always less than the independent probability of each event.