Chapter 9 Pt. 2

Question 1

Spreading activation

Answer 1

Semantic networks

• When a node is activated, activity spreads out along all connected links
• concepts that receive activation are primed and more easily accessed from memory (distance important)

Question 2

Lexical decision task

Answer 2

Participants read stimuli and are asked to say as quickly as possible whether the item is a word or not

Question 3

Coglab:Lexical decision task

Answer 3

Independent variable is association between first and second word (if associated, second word RT faster)

Called priming effect

Dependent variable: reaction time

Question 4

Coglab results

Answer 4

Word then non word had fastest reaction time then:

• nonword then word
• associated words
• unassociated words
• two non words

Question 5

Myer and Schvaneveldt-lexical decision task

Answer 5

• “yes” if both strings are words, “no” if not
• some pairs were closely associated
• reaction time was faster for those pairs (spreading activation)

Question 6

Criticism of Collins and Quillians semantic network

Answer 6

1. Can’t explain typicality effect (canary is a bird is quicker to identify than an ostrich is a bird even though they are same distance from bird node)
2. Cognitive economy (hand example)
3. Some sentence verification results are problematic for the model (e.g. pig as animal instead of mammal)

Question 7

The connectionist approach

Answer 7

• creating computer models for representing cognitive processes
• parallel distributed processing
• knowledge is represented in the distributed activity of many units
• weights determine at each connection how strongly an incoming signal will activate the next unit

Question 8

“Units” in the connectionist approach

Answer 8

Input units: activated by stimulation from enviro

Hidden units: receive input from input units

Output units: receive input from hidden units

Question 9

How learning occurs in the connectionist approach

Answer 9

• network responds to stimulus (might be random at beginning)
• provided with correct response (from feedback etc)
• modifies responding to match correct response

Question 10

Error signal in connectionist approach

Answer 10

-difference between actual activity of each output unit and the correct activity

Question 11

Back propagation (in connectionist approach)

Answer 11

• error signal transmitted back through the circuit
• indicates how weight should be changed to allow the output signal to match the correct signal
• process repeats until the error signal is zero

Question 12

Graceful degradation (connectionist approach)

Answer 12

Disruption of performance occurs gradually as parts of the system are damaged

In semantic network: 1 concept is at one node and if it’s broken it’s gone

In connectionist approach: concept represented at multiple units and if one is damaged, concept may still be there

Question 13

What type of learning process is the connectionist approach

Answer 13

A slow learning process that creates a network capable of handling a wide range of inputs

Learning can be generalized (if for e.g. new concepts share a lot of features with old concepts)

Question 14

Categories in the brain

Answer 14

Different areas of the brain may be specialized to process information about different categories

• double dissociation for categories “living things” and “non living things”
• category specific memory impairment (patient K.C and E.W could name non living objects but not living)

Question 15

Sensory-functional (S-F) hypothesis

Answer 15

• distinguishing living things depends on perceiving their sensory features
• artifacts are more likely to be distinguished by their function

Question 16

Multiple factor approach

Answer 16

Looks at how concepts are divided up within a category rather than identifying specific brain areas of networks for different concepts

Question 17

Crowding

Answer 17

When different concepts within a category share many properties (animals all share eyes and legs)

Results in higher similarity

Question 18

Hoffman and Lambon Ralph experiment

Answer 18

• presented items to subjects
• then asked them how much do you associate this item with a particular ____ (colour, motion or action)

Animals were rated higher for colour and motion

Artifacts rated higher for performed action

Question 19

Semantic category approach

Answer 19

• specific neural circuits in the brain for specific categories
• Huth et al experiment in which participants listened to stories in a scanner

Results: Similar words have similar locations in the brain

Question 20

The embodied approach

Answer 20

-Our knowledge of concepts is based on reactivation of sensory and motor processes that occur when we interact with the object

Mirror neurons: neurons that fire when we do a task or when we observe another doing the same task

Question 21

Semantic somatotopy

Answer 21

• embodied approach
• correspondence between words related to specific body parts and the location of brain activation
• Hauk et al experiment:

Movements: e.g. foot movement
Action word: e.g. kick

Lights up similar areas in the brain

Question 22

Hub and Spoke model

Answer 22

-proposes that areas of the brain specialized for different functions are linked to the anterior temporal lobe (ATL), which integrates the information from these areas

Question 23

Pobric et al TMS experiment

Answer 23

TMS stimulation of the ATL affected subjects speed of naming equally for artifacts and living things

TMS stimulation of the parietal cortex caused an increase in speed of naming only for artifacts

Question 24

TMS

Answer 24

Temporarily disrupts the functioning of a particular area of the brain by applying a pulsating magnetic field using a stimulating coil