Psychology 3130A/B Lecture Notes - Lecture 2: Triangle Inequality, City Block, Lexical Decision Task
22 Jun 2018
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Chapter 2 – The Psychology of Similarity
Goals
- What is similarity
- How similarity is involved in thinking
- Importance of similarity in thinking process
- Ways of assessing/measuring similarity
- Psych theories of similarities and how they work
What is Similarity?
- Domain-general construct
oSame principles whether visually, auditory, etc
oSimilarity is computed in the same way every time regardless of context
- Flexible (surface similarity, conceptual similarity, etc)
Similarity and the Thinking Process
Object Recognition
- Assess similarity of incoming perceptual stimuli w/ mental representations stored in memory
oEg. See a small red object => know apples are small and red => the object is an apple
-Similarity plays a huge role in object recognition!
Memory Retrieval
- Semantic memory: memorization for facts
oOrganized conceptually => will remember SIMILAR things when retrieving specific memory
- Retrieval cue must contact MOST SIMILAR representations in memory
-Spreading Activation: single target concept activated, activation spreads to other concepts
oEg. “gym” likely to spread to “muscles” more than “car”
oInfluenced by similarity (the gym is similar to muscles, not a car)
-Lexical decision task: letter strings presented to subject, required to respond quickly whether the string is a
word or not
oSHOULD respond quicker when presenting “FORK” => “KNIFE”, than “FORK” => “TRUCK”
oFaster reaction time => faster activation b/c SIMILAR concepts
-MINERVA2: model of memory, similarity b/w memory traces is major component of memory retrieval
oMemory retrieval involves a probe which finds as many exemplars as it can
oSimilar exemplars => retrieved more quickly
oProbe finds few exemplars => memories less easily retrieved
Problem-Solving
- Similarity plays role in problem-solving process
oEg. Algebra => finding patterns/similarities in strategies for problems
-Problem-space
oArrangement of current state, goal, obstacles, and operators that allow one to reach the goal
oMoving through problem state to goal state through the problem space
oKeep comparing current state to the goal state to keep track of progress in problem-solving
- Study: undergrad vs PhD physics
oAsked to sort physics problems into groups + explain reasoning
oNovices: group in physical/surface level terms
oExperts: group in deep-feature similarity related to major physics principles
oExperts use similarity to help them solve problems quickly and efficiently
find more resources at oneclass.com
find more resources at oneclass.com
Inductive Reasoning
- Generalizing/making predictions about something based on past experience
oEg. Every apple has seeds, you have an apple and you infer it has seeds
-Similarity-coverage model: inductions/inferences are based on understanding of similarity among
items/concepts being considered
- Similarity b/w 2 items determines STRENGTH of inductive inference
oEg. Every red apple you’ve ate has seeds
You find red apple, you infer it DEFINITELY has seeds
You find green apple, you infer it MAY not have seeds
oHigher similarity => Stronger inductive inference
The Assessment of Similarity
- Similarity judgement is fast and automatic
- Subjective similarity and person’s judgement of similarity can be measured
Ratings Task
- Rate the similarity b/w a Canadian penny and a Canadian nickel
- Simply asking how similar two objects are to each other
- Subject sees series of pairs of things, asked to indicate from 1 to 7 how similar the objects are
-Advantage
oRatings differ b/w people, but there should be agreement about relative similarity among objects
-Disadvantage
oNo insight on process of similarity judgement
oSensitive to contextual factors
Similarities vary based on context (comparing apples in fruit series vs. comparing apples in apple
type series)
oDifficult to assign a number to a similarity judgment (scale of 1-7)
Forced Choice Task
- Choose the most similar to a red apple:
oGreen apple
oRed plum
- Subject asked to choose “most similar” object to the target object
- Sensitive to context
oEg. If they choose green apple, then you know they judge similarity by FRUIT
oEg. If they choose red plum, then you know they judge similarity by COLOR
- Researcher can gain insight into subject’s subjective sense of similarity
Sorting Task
- Sort/Group these objects:
oMany different coins of different values/currencies
- Can sort based on country of origin, of value, of size, etc
- Sensitive to context
- Advantageous when interested in knowing HOW objects are grouped on basis of similarity
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Psych theories of similarities and how they work. Domain-general construct: same principles whether visually, auditory, etc, similarity is computed in the same way every time regardless of context. Assess similarity of incoming perceptual stimuli w/ mental representations stored in memory: eg. See a small red object => know apples are small and red => the object is an apple. Similarity plays a huge role in object recognition! Semantic memory: memorization for facts: organized conceptually => will remember similar things when retrieving specific memory. Retrieval cue must contact most similar representations in memory. Spreading activation: single target concept activated, activation spreads to other concepts: eg. Gym likely to spread to muscles more than car : influenced by similarity (the gym is similar to muscles, not a car) Similarity plays role in problem-solving process: eg. Algebra => finding patterns/similarities in strategies for problems. Generalizing/making predictions about something based on past experience: eg.
