Attention

What is Attention?

• “Everyone knows what attention is. It is the taking possession by the mind, in clear and vivd form, of one out of what seem several simultaneously possible objects or trains of thought. It implies withdrawal from some things in order to deal effectively with others, and is a condition which has a real opposite in the confused, dazed, scatterbrained state which is called distraction” William James (1890)

Varieties of Attention

• Selective Attention

• Attention as a Resource

• Control vs. Automaticity

Selective Attention

• The ability to focus on a subset of perceptual information that reaches the senses

• When participants are told which year to attend, they can effectively filter out the other non-relevant message

• Task is easier if physical characteristics of the two voices differ (if voices sound similar it is difficult to differentiate)

• Our ability to attend is in some part reliant on the environment and whether or not the stimulus are similar

• What happens to the unattended message?

  • Is all that info lost?

  • What at stage of listening does the unattended message get filtered out?

Evidence for the Late Selection

• Cocktail party effect

  • Despite blocking out background chatter during conversation many of us will notice if our name is spoken in a different conversation

  • Suggests that at least at some level some information from an unattended channel gets processed at the semantic level

• Treiman’s Shadowing Study (1960)

  • Shadowed message suddenly shifted to unattended channel

  • Instead of continuing to repeat attended channel, participants started to repeat the unattended channel to maintain the meaning of the sentence

• Must be some form of semantic analysis in unattended channel

Selection can be Space-Based- Spotlight Metaphor

• Attention acts as a spotlight selecting a region of space for further visual processing

• Overt: movement of eyes toward attended regions

• Covert: Eyes remain stationary shift of “minds eye”

• Attention is often shifting covertly with conscious overt movement

• Posner Cueing Exam: WILL BE ON THE EXAM!!   

Selection can also be Object-Based

• We can selectively attend to either the face or house presented at the same spatial location

• RT faster on same object trails compared to different object trials, even though the target is equidistant from fixation in both cases

Visual Search

• Pop-out (feature search is carried out in parallel

• Conjunctive search is carried out in serial

• Conjunctive search requires feature ‘binding”, which is attentional demanding

• Attention is the ‘glue’ that binds features together

• It is harder for us to find something if it is rare

Illusory Conjunctions

• When attention is divided participants often make ‘conjunction errors’- falsely believed that “green T” was presented if display contained ‘green’ and ’T’ features

Selection at a Cost- Inattentional Blindness

• Participants are asked to focus on the cross and judge which of the two lines is longer many participants were unaware of the black square flashed unexpectedly

• However, when faces were flashed they were detected 85% of the time

• Black square goes unnoticed while the face does not

What is Temporal Resolution of Selective Attention

• A moment that comes after complete attention may be missed

• Participants are asked ti identify two red letters from a rapid stream of distractors

• Vary the time between T1 and T2

• Accuracy of reporting T2 is dependent on how quickly it follows T1

  • The closer to T1 the less we are able to identify it

  • I.e. the period after we are paying attention comes at a cost

  • If the stimulus is emotionally charged however we can focus on it

Attention as a Resource

Can We Attend to More Than One Thing At A Time?

• Our complex environment often demands that we performs multiple tasks simultaneously- divided attention

• Despite considerable ability too process information in parallel there are limits as to the types of mental operations that can be carried out simultaneously

Capacity Limitations

• There is a limited amount of mental ‘energy’ that can be spent at any give moment

• When we actively attend to a stimulus a portion (or all) of this limited pool of resources is taken up, leaving little left over for other tasks

• Central Processing Bottleneck

  • At what processing stage does this limitation arise?

  • Central process occurs for only one task at a time

  • More complicated tasks will slow down the processing of other tasks

  • When do we loose the ability to process in parallel

  • Stimulus onset asynchrony (SOA): how much time is there between on stimulus and the next

  • Making a decision and selecting a response cannot be done in parallel

  • Longer SOA would lesson the slack and the RT2 response time would be quicker

Dual Task Perfomance- Summary

• Performance on Task 2 suffers at short SOAs because response selection/decision processes for Task 1 drain resource pool

• This forces response selection/decisions processes for Task 2 to ‘wait’ until this stage is complete for Task 1, prolonging overall response time for Task 2 (PRP effect)

• The PRP effect can often be reduced, but not entirely eliminated with practice

Sustained Attention

• Are there limits to how long we can ‘concentrate’?

• What happens when we’re forced to maintain focus for extended periods  of time?

• How do we asses this in the lab?

  • Sustained attention to response task (SART)

  • Vigilance Task (Mack worth Clock Task)

• Under-load View- attention has been spent on ‘mind wandering’ which we are now attending to due to under stimulation

The Role of Task-Unrelated Thoughts (TUT)

• As mind wandering goes up attention goes down

• Increase in mind wandering over time leads to vigilance decrement

ON EXAM!!!!

Control vs, Automaticity

Control Processing

• A process that requires conscious use of attentional resources

• Allows for purposeful, goal-directed behaviour

• Effortful and cannot be done mindlessly

  • e.g. driving a car

Automatic Processing

• A process that does not require attention for its execution

• Can be carried out unconsciously with little awareness

Stroop Effect

• Faster Res for congruent (GREEN) relative to incongruent (GREEN) items

• Must suppress automatic process of word reading in order to name ink colour- examples of a controlled process

• Automatic and controlled processes placed in opposition

• Involves activation of multiple brain regions

  • ACC - Anterior Cingulate Cortex (conflict detection)

  • DLPFC - Dorsal prefrontal cortex (active control to suppress word reading)

• Privy to environmental influences:

• Strategies/expectations can help effectiveness of controlled processes

• Logan & Zbrodoff (1979): vary block-wide proportion of congruent trails

• If the amount of incongruent stimulus s large it will shorten the Stroop effect as we learn through experience to not word read

How Flexible is Cognitive Control?

• Mental Set: A preparatory mental state that ‘tunes’ cognitive processing to achieve a particular goal

  • Gets your brain ready to do something

  • We have to switch the mental set when we have a different type of task to do

• We are not good at switching from mental ‘set’ to another even when the task is simple

• Switch cost- amount of extra time it takes for us to complete a task when we switch mental set

  • Cost gets bigger with age

  • Switch cost is not eliminated when more time to prepare is given although it does get smaller

  • Voluntary task switching is just as costly as forced task switching

• Residual switch cost: switch cost that remains even after people are given time to prepare for task switching

Instance Theory if Automaticity

• Performance is initially controlled by an algorithm

• Overtime, reliance on this algorithm dissipates , as more and more memory instances accumulate

• Performance is eventually based on the revival of instances from memory

• “Solving the problem” gives way to “remembering the solution”

• Performance improves with practice following a ‘power law’

• If training leads participants to retire instances from memory, than RT should no longer increase with number of dots

• Cost of automaticity = if routine is changed it is useless (I.e. it does not generalize well)

PSYC*2650- Memory

The Many Forms of Memory

• Almost all behaviours are shaped by some form of memory

• System vs. Processes

• Forgetting is more like information being unavailable rather than information being gone

Traditional Memory Models

Sensory Memory

• Sensory memory is the name given to the store that briefly retains sensory information

• Hasn’t undergone meaningful processing

• Thought to store sensory information in a raw or uninterrupted form

• Sensory input from the environment contains far too much information for the brain to process all at once

  • We need something to filter what is important

• The sensory memory system is thought to be responsible for two major phenomena in the visual system:

  • 1. Visible persistence

    • Both peripheral (retinal) and neural origins

    • Like an “afterimage”- visual information remains visible briefly after it’s physical presentation

    • Duration of persistence is inversely related to stimulus duration

  • 2. Informational persistence

    • Information can be extracted from a stimulus for a brief period of time after the stimulus itself is no longer present

    • How much information can be apprehended from a brief exposure to a visual stimulus?

    • People can typically only retrieve 3-4 out of 12 letters

• Iconic memory

  • Large capacity

  • Brief duration

Short-Term/ Working Memory

• Combines storage aspect of STM with active attention component

• WM is a memory system that allows for short-term retention AND active manipulation of information

WM as a Trait

• Individual differ in terms of their working memory abilities; WMC predicts many different outcomes

• Working memory capacity (WMC): “is not really about storage or memory per se but about the capacity for controlled, sustained attention in the face of interference or  distraction” (Engle, 1999)

Distinction Between Working Memory and Long-Term Memory

• Primacy Effect: Rehearsal of the first few items results in transfer to LTM

• Recency Effect: ‘Dumping out’ of information in WM - recent info still left in the working memory

• Predictions:

  • 1) preventing rehearsal of last few items should wipe out recency effect

  • 2) allowing for more rehearsal during item presentation should boost primacy effect

• Variables that affect the primacy effect do not effect the recency effect as both effects are controlled by different  systems

Long-Term Memory

Declarative Memory

• Episodic Memory

  • Bound to context (i.e. time and place)

  • Concerned with personal past

• Semantic Memory

  • Not contextually-bound

  • Concerned with general knowledge knowledge and facts

Episodic Memory

• Laboratory-based method that allows fro experimental examination of learning and memory encoding: study-test paradigm

  • Study: judge the following words in terms of your liking

  • Test: what were the words you say 20 minutes ago (recall) was this one of the words you saw (recognition)

• Study phrase serves as episode whose details need to be recovered at test

Processing Principles

• Craig & Lockhart (1972)

• Critical how info is processed at time of encoding -> level/depth of processing

• Different levels of processing words:

  • Perceptual feature analysis

  • Processing of sounds (phonology)

  • Processing of meaning (semantics)

• Empirical test of framework with incidental orienting tasks (level of processing induced by experimenter)

• Typical advantage of deep over phonological over shadow encoding on recognition memory test

• LoP effect does not just reflect differences in time spent processing item at encoding

• Instead type of processing, and integration with existing knowledge critical (integration more effective in yes decisions )

• There are limits on when semantic processing is beneficial for memory

• Memory performance depends not only on how information is encoded by also on the way in which it is tested -> transfer-appropriate processing

• Memory is related to how it is encoded (meaning, sound, etc.)

• Memory for an event depends on the interaction between properties of the encoded information and properties of the retrieval cue -> encoding specificity principle

• Contextual reinstatement: change of circumstances between learning and test decreases memory

• State-dependent memory: you will remember info better if you are in the same state as when you learned information in (e.g. drunk, sober, etc.)

• Mood -dependent memory: you will remember info better if you are in the same mood as when you learned information in (e.g. happy, sad, etc.)

Autobiographical Memory

• Childhood/Infantile Amnesia: little reliable memory for events experiences before four years old

  • Paucity of language (difficult to ‘label’ our experiences)

  • Difficultly binding different elements of an experience into a whole

  • We have difficultly binding memories which is why we have issues saving these memories

• Reminiscence Bump:  enhanced memory for (episodic and semantic) facts of adolescences and young adulthood

  • Disproportionate enhancement of memory from 18-30 yo

  • Many autobiographically consequential experiences- experiences that shape a persons identity

  • Highly distinctive events- birth of first child, marriage, etc.

• Semantic memory: information in semantic memory is though to be organized in a network with related concepts near each other

  • Things are connected by similarities (red= fire, apples, stop signs, etc)

  • Pieces of information are all connected and can connect each other

  • Spreading activation: activation of one concept ‘primes’ the activity of related concepts

  • Semantic priming- RT to targets is faster when preceded by a related primes  (i.e. nurse- BUTTER; bread- BUTTER)

    • Reaction time is much faster when words are related

• Semantic priming is influenced by automatic spreading activation activation AND controlled expectations

  • When prime is BODY expect a target from the building category (i.e. BODY- door) RT will become faster over time than automatic processes RT as we have overwritten the automatic processes

  • Spreading activation yields facilitation at short SOAs, but inhibition at long SOAs as expectancy develops

Non declarative (Implicit)  Memory

Memory Without Awareness

• Prior experience can shape behaviour without conscious awareness

• Direct tests: probes memory with explicit reference to prior experience (e.g. recall; recognition)

• Indirect tests: probes memory without making any reference to prior experience (e.g. priming)

  • Measures behaviour to demonstrate how memory affects behaviour

• Example of direct vs. Indirect:

Sequence Learning (Nissan & Bullemer 1987)

• Sequence learning- patients shown four boxes and asked to push a button (1-4) about where the circle shows up in the box

  • The circle should follow a subtle pattern

  • RT’s of when people press buttons get faster as they implicitly learn where to except the next

  • RT’s are faster to trained sequences as compared to random sequences

• Implicitly Sequence Learning is often acquired without any explicit knowledge of actual sequence itself

• Sometimes environment is predictable and the brain will implicitly pick up on these patterns even when we are not consciously aware of them

Jacoby experiment

• Jacoby (1983) proposed that explicit memory was conceptually-driven and implicit memory was data-driven

  • Phase 1: read aloud a word preceded by (a) no context, (b) an antonym read silently, or (c) an antonym to which the word was generated

  • Phase 2: Given one of two tests

    • direct test- recognition test for words in Phase 1

    • Indirect test- identify briefly presented word

• Recognition in direct test is best when word is generated in Phase 1

• Perceptual identification is better in No Contact condition

• Recognition is better in the Context and Generate conditions

• The same manipulation has different effects depending on whether the test is direct or indirect- different processes involved in each type of test

• If explicit and implicit were the same and playing by the same rules than they should respond the same thus proving they are different

• Explicit contamination-Just because the experimenter doesn’t make reference to the encoding list doesn't mean that participants want intentionally use words from the lost to complete each stem

Method of Opposition (Jacoby, 1991)

• How can we test apart implicit vs. Explicit influences on performance?

• Two different conditions:

  • Inclusion: complete stem with word from list or with first word that comes to mind

  • Exclusion: complete stem using words no in the encoding list

• If stems are still completed with studied words in the exclusion condition, then it must be an implicit influence of prior experience

• THIS WILL BE ON THE MIDTERM

Memory Distortion and Illusions

• Memory is not always accurate; susceptible to various forms of error

• Important real-world implications

• Legal system- wording of questions can inform an individuals memory

• Medicine- questions the doctors ask can inform and shape our memory of our symptoms

• Different types of memory errors

  • Are all errors in episodic memory errors of omission?

    • i.e. lack of availability of information due to poor encoding and/or forgetting

  • Or do we also make errors of commission

    • i.e. false remembering of episode or episodic detail that happened in different way or even never happened at all?

Memory Metaphors

• Memory as a storage warehouse

  • Once memory is retrieved it is just as it was when it was stored

• Memory as a detective

  • Memory as an active process of inference and re-construction

  • Reconstruct the past using clues, inferences and heuristics (rules of thumb)

Episodic Memory Illusions

• Merry illusions studied with Deese / Reedier-McDermott (DRM) paradigm:

  • Highly robust effect of false remembering of critical lures in recall and recognition

  • Occur even when subject is informed about potential for memory illusions and instructed to avoid them

  • Underscores the powerful role of inference and re-construction in episodic memory

What Leads to False Memory?

• Role of heuristics

  • Rules of thumb that guide our judgements

  • Serve to maximize cognitive cognitive economy

• False remembering in DRM paradigm results from an over-reliance on gist information

• Note that relying on such simple heuristics can have a profound effect on subjective experience

• Prone to error but often right

• When they work they work incredibly well

• ‘False Fame’ Study by Jacoby et al. (1989)

  • Phase 1: participants read a list of fictitious names aloud for a study or pronunciation (spread and accuracy)

  • Phase 2: later, shown a lost of names along with old and new fictitious names. Test was either immediate or delayed (24 hr)

  • Reminded that the earlier list was non-famous name

  • Results: probability of judging a name as famous

    • Famous= .55

    • Non famous

      • New= .08

      • Old = .16

  • Some non famous names became famous overnight

  • That is the of “familiarity” was miss attributed to the fame of the name rather than the source (it was on the first list)

  • There is no such effect if the test is immediate because the surge of the familiarity is recalled-that is “I recall it being on the list”

The Role of Heuristic in Memory Judgements

• Jacoby & Whitehouse (1989)- manipulate fluency of test items with masked priming

• Showing individuals a brief flash of the word ‘river’ will make it more likely for participants to misattribute river as a word on the list

• When unaware of the matching prime, participants attribute facilitated processing to prior exposure

• When aware of the matching prime, participants attribute facilitated processing to the prime

• Fluency Heuristic leads to false recognition

• Fluency Heuristic- judgements of familiarity are the result of ease of processing (fluency)

  • Fluency may be due to prior exposure (as in false alarm)

  • Fluency may be due to experimental manipulation (illusion familiarity)

Episodic Memory: Suggestibility

• Individual’s tendency to incorporate incongruent for from external sources into personal recollections from episodic memory

• Situations in which suggestibility can be important factor:

  • Eyewitness tetsimony in police investigations and courtroom

    • Can reports from eyeywtiness reflect memory illusions due to suggestions during interrogations

    • When witnesses have high confidence in their memory they are often right

    • Witness’ memory can only be questioned once to avoid suggestion

  • Recovered memories from abuse in psychotherapy

    • Can they reflect memory illusions due to suggestions in therapy?

• E.Loftus conducted groundbreaking research on suggestibility in memory

  • Demonstrated the misinformation effect when people who witnessed an event are later exposed to new and incongruent information about it their recollections often become distorted

  • Shown a video of a car pulling up to a stop sign and getting to a collision and then ask “how fast was the car going when they car pulled up to the yield sign” and people will misremember the sign as a yield sign

  • Wording also greatly important (smashed vs. Hit car)

Memory Illusions and Emotion

• Are memories for emotional, impactful events immune to error

• “Flashbulb memories”

• Tend to be believed with greater confidence

• Tend to be associated wth great vividness

• But are they more accurate than everyday?

  • Talarico & Rubin (2003)

  • Asked 54 people to answer questionnaires about their memories for the 9/11 attacks and ordinary events right after 9/11

  • Re-tested either 1 week later, 6 weeks later or 32 weeks after

  • Participants recalled emotional events with higher confidence but were not anymore accurate than everyday events

Memory Disorders

Patient H.M

• When told a joke, despite the fact H.M had no recollection of the joke he acted as though he had heard it before and was less amused

Amnesia

• The hippocampus is thought to be critical for long-term declarative memory

• Medial temporal lobes- in the temporal lobe and contains the hippocampus

• Anterograde amnesia- inability to form new lasting memory

  • Most patients suffer at least a little anterograde

• Retrograde amnesia- inability to remember events that occurred prior to injury

  • Usually only forget events around the time you suffered the injury (you won’t forget your entire life just more recent memories)

• Global amnesia - having both anterograde and retrograde amnesia

Are all forms of memory impaired?

• Amnesia often have preserved implicit memory and can still learn even if they cannot recall it

• Impairment in tests of declarative memory (e.g.g free recall, cued recall)

• Normal performance on indirect test of memory (e.g. stem completion- implicit memory)

• Normal semantic priming

Neurodegenerative Dementia

• Progressive and slow decline of nervous system

• Symptoms referred to as “dementia”

Alzheimer’s Disease

• Build up of neurofibrillary tangles and amyloid plagues

• Plagues and tangles “choke off” neurons killing them

• AD can only be formally diagnosed  post-mortem

• Post-mortem analysis often finds plaques and tangles present in asymptomatic individuals

• Strong genetic component

• Difficult to diagnose as many diseases are similar to one another

• Education and exercise seems to be a protective factor

• Some have suggested it is more prevalent among women but it is unclear as to why (seems to be due to longer life expectancy)

• Neurodegeneration often begins in medial temporal lobe structures (e.g. entorhinal cortex)

• Results in progressive memory decline

• Pathological changes can begin 10-20 years before symptoms appear

• Episodic memories are typically first affected by degeneration spreads to other cortical areas, yielding additional cognitive impairment as disease progresses

Concepts & Categories

• Mental representations of classes of things (Murphy, 2002)

• ‘Glue’ that hold out world together

What are Concepts for?

• Concepts allow us to make sense of the world, and to make accurate predictions about novel items of a category

The Classical View of Concepts

• Grounded in philosophical tradition of formal logic

• Concepts can be defined by the presence or or absence of features (e.g. if conditions A,B,C and D are satisfied, then object X belongs to category Y)

• Necessity and Sufficiency: Properties A, B, C, and D are both necessary and sufficient for object X to be categorized as an instance of Y

• Concepts are merely lists of necessary and sufficient conditions

Problems with Classical View

• Wittgenstein: What are the necessary and sufficient conditions for the concepts of ‘game’?

• Even fairly simple concepts do not have a definition making it difficult to create a concept list

• Wittgenstein: What are the the necessary and sufficient conditions for concept of ‘game’

  • Inconsistency with an individual-

    • McCloskey and Glucksberg (1978): when asked whether an olive is a fruit, people changed their minds when asked more than once

  • A dog is a dog is a dog is a dog?

    • Classical view predicts that all members of a category are ‘equal’. In other words, a Chinese crested dog is equally as good of an example of ‘dog’ as a golden retriever

Typicality and The Fall of the Classical View

Eleanor Rosch and Typicality

• Rosch: members of a category differ in terms of how well they represent the category as a whole. A sparrow is a typical bird, whereas a chicken is a atypical bird.

• Typical it’s are categorized more quickly and more consistently

• What makes an item “typical”?

• Family Resemblance- the extent to which exemplar X shares attributes with other exemplars in category A, but not exemplars from carry B, determines ‘typicality’

Typicality

• Exemplars of a category can vary widely in terms of how ‘typical’ they are for that category

• Categorization behaviour is sensitive to exemplar typicality

• Rips, Shoben, & Smith (1973): participants were faster to verify the robin is a bird than ostrich because it is a more typical

• Induction: the ability to generalize or extend properties of some category members to others

  • Premise: Robins have sesamoid bones?

    • Do sparrows have sesamoid bones?

• Rips (1975): People are more likely to believe sparrows have  sesamoid bones when the premise involves a typical category member (e.g. robin) than when we premise involves an atypical category member (e.g. penguin)

Typicality and Fear Generalization

• Dunsmoor and Murphy (2014): Does stimulus typicality determine how broadly conditioned fear is generalized?

  • Typical group: Typical mammals paired with aversive shock during conditioning phase

  • Atypical group: Atypical mammals paired with aversive shock during conditioning phase

• Does stimulus typicality determine how broadly conditioned fear is generalized?

  • Typical mammals paired with aversive shock during conditioning phase

  • Atypical mammals paired with aversive shock during conditioning phase

• Does stimulus typicality determine how broadly conditioned fear is generalized

  • Broad conditioning makes generalized fear easier

Alternatives to the Classical View

Prototype Theory

• Concepts are represented by a categorical ‘prototype’

• Prototypes capture the central tendency of a category- ‘summary’ representation

• Categorization is based on the similarity between an exemplar and the prototype for that concept

Posner and Keele (1968)

• Training Phase

  • Participants see multiple exemplars from ‘different’ categories

  • Exemplars consist of low and high distortion items from each ‘category’

• Test Phase

  • Participants are shown new exemplars and the prototypes themselves from each ‘category’ and asked to classify them

• Results: Better accuracy for low vs. high distortion exemplars

• Accuracy highest for prototypes despite never seeing them

• Exposure to exemplars created a ‘prototype’ representation for each category

• Categorization of new exemplars was based on comparison to prototype representation

Exemplar Theory

• Subjects do not form an abstract ‘prototype’ for each category

• Individual exemplars are stored in memory

• Categorization is based on the similarity between a new test item and stored exemplars

Whittlesea (1983)

• Created categories based in CVCV strings (i.e.FRUIG, NOBAL) as prototypes

• Only children of the words are shown and people were told to guess which parent the word came from

• Similarity of exemplars to prototype varied by changing one, two, or three letters from category prototype

• Do people categorize based on similarity to stored exemplars?

• Exemplar theory suggest as we move away from the children of the exemplar it should become more difficult to recognize as belonging to that category

• Prototype theory suggests as we move away it should not matter as we are comparing the example to a prototype we’ve made up

Brooks, Norman, Allen (1991)

• Seasoned dermatologist and inexperienced medical residents shown labelled pictures of different skin diseases- asked to judge how ‘typical’ each one is of that diagnostic category

• The asked to categorize new pictures (unlabeled) that were from the same diagnostic categories, but were either superficially similar or dissimilar from the original images

• Results showed that doctors were more likely to diagnose images that looked typical to examples they had just been shown

Alternatives to Classical View

• A general consensus regarding the correct theory of concepts (prototypes vs. Exemplars) has yet to be reached

• There is evidence for both theories

• Some have suggested that when leaning a new category, people initially use individual exemplars to guide their categorization decision , but switch to using a prototype once sufficient experience accrues

  • Not whoever eve experts rely on similarity between novel exemplars and previously encountered examples (possibly even more than novices)

The Role of Prior Knowledge

• Majority of research on concepts has focuses on category leaning with artificial materials

  • This is done to ensure that prior knowledge can’t influence category learning

  • Allows researchers to examine ‘pure’ category representations

• However, most new concepts that we learn are in some way associated with related  prior knowledge

Lin & Murphy (1997)

• When groups were told different uses for an item then showed a collection of images of FINSIHHHHHH

• Prior knowledge has a large impact on how people categorized objects

How are Concepts Organized?

• Categorical knowledge is structured in a nested hierarchy- taxonomic organization

• Transitivity- All dogs are mammals, and all mammals are animals. Therefore all dogs are animals

• Property Inheritance- all lower categories inherit the properties associated with higher taxonomic

Importance of Basic Categorization

• Preferred Level of categorization

  • Most often used when spontaneously naming an object

• Balance the trade between informativeness and distinctiveness

• Are often the first categories that children learn based on sorting and naming

Rosch et Al. (1976)

• Faster Res to verify category image pairs when category label is at basic category level

• Demonstrates that there is seemingly something special about the basic level (default level)

• Basic category identification is the last to degenerate in patients with dementia

Categorization and Expertise

• Does expertise in a particular domain affect preferred level of categorization?

• Expertise on some level represents categorization at its highest level

• It takes a dog expert the same amount if time to classify a cocker spaniel as a

  • Expertise eliminates the advantage FINSIH THIS

Chi Feltovich, Glaser (1981)

• Asked novices and experts to classify different types if physics problems

• Novices tended to sort problems based on superficial properties, whereas experts tended to sort based on underlying commonalities, forming few overall groups

• Experts know when to lump and when to split when appropriate and are not distracted by false commonalities