Sem2 Week 6

A grouping of things that are equivalent or similar; also called a concept. Members of a category are called instances.

Learning (less memory), generalisation (infer new info), prediction, interaction, and communication.

Plato’s idea that good categories reflect real divisions in the world — but in practice, those divisions aren’t always obvious.

A category defined by a set of necessary and sufficient rules. E.g. triangle, integer, bachelor.

Space and time both depend on the number of rules.

(1) Many categories are hard to define with rules eg. Chair, Foods. (2) They don’t account for typicality effects (e.g. robin vs ostrich as birds) or ambiguity (e.g. is a priest a bachelor?).

The finding that some members of a category are judged more typical than others — e.g. people respond faster to ‘robin’ as a bird than ‘ostrich’.

A category defined by an abstract template that averages over all members — not a concrete example, but a generalised representation.

Space: small (one prototype). Time: fast (compare to one prototype). Learning: modify the prototype by incorporating the new example.

A category defined by a set of previously encountered specific instances, rather than an abstract average.

Space: large (stores many exemplars). Time: slow (must compare to multiple exemplars). Learning: fast — just store the new instance.

A category defined by subjective sensory experience, such as colours, tastes, or emotions. May have biological bases but is represented experientially.

A category defined by a framework of related concepts and relations — more complex and ambiguous than rules. Common for abstract and social concepts like love, justice, or infinity.

A category created in the moment to serve a current goal. Eg. Object that could be used as a paper weight. No long-term storage; high processing cost. Often relevant to creativity.

Prototypes are abstract averages (generic); exemplars are specific stored instances (concrete). Prototypes are space-efficient; exemplars are slower to query but faster to update.

A symbol that stands for something (its referent). A symbol is said to be grounded when it is attached to a concept.

Mostly yes — there is no inherent reason ‘cat’ refers to a cat. The main exceptions are onomatopoeia (buzz, meow), where the sound mirrors the meaning.

A cross-cultural finding that people consistently match rounded shapes to round-sounding words (bouba/maluma) and spiky shapes to sharp-sounding words (kiki/takete), suggesting some sound-meaning links are not fully arbitrary.

A 2021 study (Ćwiek et al., Phil. Trans. R. Soc. B) found the effect holds across speakers of 25 languages, 9 language families, and 10 writing systems.

A conventional pairing of meaning and sound with no inherent connection between the two — the basis of most words in a language.

The full set of words a person knows in their language. It is thought to be organised as a hierarchy or network, mirroring how our concepts are structured.

By adulthood, people know around 40,000 words and idioms. Word meaning is accessed by a listener in ~0.2 seconds. The brain takes ~0.25 seconds to name an object, and another ~0.25 seconds to program articulation.

A dramatic acceleration in children’s productive vocabulary that occurs during the second year of life.

A research tool developed from 1975 to study how children acquire language — crucially, it studies children before they have fully learned language, since that is when acquisition can be observed.