Concepts and Categories

• Concepts are mental representations of things, people, and their properties, which help organize information in the brain
• Concepts are built through exposure to different regularities and patterns

Categories

• Categories encompass all possible examples of a concept and aid in organizing concepts
• Examples include different types of schools like culinary, graduate, and high schools

Definitional Approach

• The definitional approach involves setting up conditions for an object to enter a category
• Definitions are used to organize categories in the brain

Problems with Definitions

• Not all category members share the same features
• Ludwig noted the problem of shared features and introduced the idea of family resemblance in the 1950s
• Family resemblance suggests similarities and relationships exist among category members, but without clear boundaries, existing on a continuous scale

Prototypes

• Prototyping, according to Eleanor Rosch, involves creating an average representation, which is the most typical example of a concept
• Prototypes are useful when learning something new

Categorical Ratings of Typicality

• Categorical ratings of typicality, demonstrated by Eleanor Rosch, involve rating examples based on how well they represent a concept
• In experiments, participants rate examples with values, where 7 indicates poor similarity and 1 indicates very good similarity, developing a continuous scale with new objects

Sentence Completion/Listing

• Sentence completion/listing, studied by Mervis, involves individuals filling in the blanks in a statement without examples
• The first thing that comes to mind is considered the most prototypical

Reaction Times

• Reaction times are faster for items closer to one's prototypes, as they are readily available in the nervous system
• Real categories are determined by individual experiences, so universals cannot be derived from this

Exemplars

• Exemplars involve comparing new instances to real members of a category, rather than relying on an average
• Information is stored as both prototypes and exemplars

Advantage of Exemplars

• Useful with unusual cases, instead of the prototype of sandwich, you have different exemplars, instead of an average idea.
• Determines which category members are most frequent
• Aids in learning exceptional category members and capturing edge cases

Hierarchies

• Hierarchies are based on the basic level of categorization

Superordinate Level

• Superordinate levels include broad categories like "animals"

Basic Level

• Basic levels, such as "birds", involves the most naming efficiency from a presented image
• Naming something at the basic level results in the fastest reaction times, compared to superordinate and subordinate levels
• Level of expertise and experience with an object influence the perceived basic level
• Tanaka and Taylor's bird study showed that experts identify specific types of birds, while non-experts identify them as "birds"

Subordinate Level

• The subordinate level involves specific examples, such as sparrow, robin, or penguin

Sensory-Functional Hypothesis

• It posits two different knowledge structures: one for sensory attributes (how things feel, sound) and another for functional roles (how objects are used)
• Dissociation between sensory and functional knowledge structures exists for attributes and uses
• Patients with problems with artifacts know how to use them
• Individuals with sensory impairment would not be able to have sensory knowledge

Multifactor Approach

• The multifactor approach involves giving concepts and descriptors to people and describing how much they associate with them.
• Like a tiger and a nail and associate them with color, motion and action
• Defining properties of a concept can be determined this way
• Concepts are rated for similarity across factors
• Mechanical devices have high ratings in form and function, as well as color and motion
• Knowledge structures are stored in the brain in a distributed way
• Musical instruments and Vehicle descriptions fit this model

Semantic Categories

• Semantic categories are figured out by where things are in the brain
• Idea, smell, taste and sound of stuff are not all in just one place

Neural Circuits

• Specific categories have neural circuits, which can be identified using fMRI to measure oxygen levels in the brain
• Participants watch a movie and code elements like buildings and animals, correlating the numbers with brain activation from fMRI

Distributed Processing

• Brain processes are local and distributed

Embodied Approach

• The embodied approach activates sensory/motor processes related to objects, linking knowledge to interaction
• Knowledge is stored as a combination of how an object is used and its appearance, reflecting the movements the body makes with that function
• Embodied cognition suggests we cannot think about functions without thinking about movement, connecting the ability to perceive with ability to interact

Brain Stimulation

• Electrodes inserted into the frontal lobe (premotor cortex) between prefrontal areas and the movement center recorded neuron activity in non-human primates during food picking and eating
• The grasping stage revealed neuron firing when picking up food
• Mirror neurons in monkeys fire both when performing an action and when observing someone else performing the same action

Movement/Concept Overlap

• Movement/concept overlap studies, like Hauk's, involve moving the body (up, down, left, right) while under a scanner measuring blood flow, reveals activation in the cortex
• People read words that are actions, not performing movements, just reading the word of action

Semantic Dementia

• Semantic dementia has been helpful to how knowledge is structured on the brain
• Involves a hub (large brain area that control how we way the distributed network items) and spoke model

Anterior Temporal Lobe

• Anterior temporal lobe integrates information from each of the spots
• There are distributed spots that the anterior temporal lobe integrates

TMS

• TMS, or transcranial magnetic stimulation, involves using a metal coil over the brain to disrupt brain activity with magnetic pulses and is calibrated by finger movement
• Pobric's 2010 study compared disruption using a TMS magnet in the parietal lobe, where there are spokes, with brain stimulation in the anterior temporal lobe and parietal lobe
  • Before stimulation was normal
  • During stimulation, reaction times were longer and slower for artifacts in the anterior temporal lobe, but in the parietal lobe the reaction time for living animals was faster