From Prototypes to From Prototypes to Abstract IdeasAbstract Ideas

A review of On The Genesis of A review of On The Genesis of Abstract Ideas by MI Posner Abstract Ideas by MI Posner

and SW Keeleand SW KeeleSiyi Deng

Concept and CategorizationConcept and Categorization

►What cognitive events happen when you tWhat cognitive events happen when you think about a hink about a chairchair? ?

►How is the concept of How is the concept of chairchair represented in represented in the cognitive system? the cognitive system?

►Surely, a seat at a formal dining table is Surely, a seat at a formal dining table is “chair", but what about a recliner, a stoo“chair", but what about a recliner, a stool, a couch, or a tree stump?l, a couch, or a tree stump?

Categorization and ConceptsCategorization and Concepts

►Why do we need categories? Because Why do we need categories? Because they make our life easier. (Coding of they make our life easier. (Coding of experience and Licensing of inferences.)experience and Licensing of inferences.)

►Categorization and Concepts are Categorization and Concepts are inseparable, concept is a mental inseparable, concept is a mental representation of a category.representation of a category.

►How we think and what we can learn is How we think and what we can learn is largely determined by how we largely determined by how we represent concepts.represent concepts.

SimilaritySimilarity

► It seems that our rule of categorization is It seems that our rule of categorization is to maximize within-category similarity to maximize within-category similarity while minimize between-category while minimize between-category similarity.similarity.

►One traditional approach to measure One traditional approach to measure similarity is to assign objects to locations similarity is to assign objects to locations in a multidimensional space thus the in a multidimensional space thus the metric distance between any two of them metric distance between any two of them could be measured in the Geometric could be measured in the Geometric standard.standard.

SimilaritySimilarity

An example of a two-dimensional space for representing the similarity relations among some common fruits and the category of fruit itself.

Abstract IdeasAbstract Ideas

►Posner and Keele’s designed a series of Posner and Keele’s designed a series of experiments to study how does general inexperiments to study how does general information about individual objects is abstformation about individual objects is abstracted and what is stored during the learnracted and what is stored during the learning process.ing process.

Abstract IdeasAbstract Ideas

Hypotheses about abstraction:Hypotheses about abstraction:I.I. The prototype is abstracted and it alone The prototype is abstracted and it alone

is stored)is stored)

II.II. The abstracted prototype is stored in The abstracted prototype is stored in addition to the individual instances.addition to the individual instances.

III.III. Prototype only enjoy a higher recognition Prototype only enjoy a higher recognition level than individual instances.level than individual instances.

IV.IV. No abstraction takes place during No abstraction takes place during learning.learning.

The Dot Pattern Prototype The Dot Pattern Prototype TestTest

►The method developed by Posner and The method developed by Posner and Keele to investigate the origin and Keele to investigate the origin and storage of concept representations.storage of concept representations.

►Using patterns of dots, rather than well-Using patterns of dots, rather than well-known concepts (such as “chair”).known concepts (such as “chair”).

►Use statistical distortion rules to get Use statistical distortion rules to get patterns varied around a prototype.patterns varied around a prototype.

►Benefit of dots: systematic and Benefit of dots: systematic and controlled.controlled.

The Dot Pattern Prototype TestThe Dot Pattern Prototype Test►Nine Dots within a 30 x 30 matrix to Nine Dots within a 30 x 30 matrix to

form prototype patterns of a triangle, form prototype patterns of a triangle, letter M and letter F, as well as a letter M and letter F, as well as a random pattern.random pattern.

►For each of the four prototypes, six For each of the four prototypes, six distortions were constructed at each of distortions were constructed at each of three different levels (1, 5 and 7.7 three different levels (1, 5 and 7.7 bits/dot).bits/dot).

Example Pattern of DotsExample Pattern of Dots

Posner and Keele’s ExperimenPosner and Keele’s Experimentsts

►Experiment IExperiment IIn the first step, 3 distorted versions (ranging froIn the first step, 3 distorted versions (ranging from small distortion to large distortion) of a same m small distortion to large distortion) of a same prototype were presented to 3 different groups prototype were presented to 3 different groups of participants, this is the learning process. After of participants, this is the learning process. After learning, in the second step, they were asked to learning, in the second step, they were asked to classify some more major distortions, together classify some more major distortions, together with a control group (no learning).with a control group (no learning).

Experiment IExperiment I►Results:Results:

In the first step, Level 1 Group (which learn In the first step, Level 1 Group (which learn the small distortion version) performs better the small distortion version) performs better than Level 5 Group (large distortion than Level 5 Group (large distortion version). version).

However, during the second step, Group 5 However, during the second step, Group 5 are significantly better than Group 1.are significantly better than Group 1.

Posner and Keele’s ExperimenPosner and Keele’s Experimentsts

►Experiment IIExperiment IIThe purpose of this Exp. Is to eliminate some potThe purpose of this Exp. Is to eliminate some potential problems that might affect performance iential problems that might affect performance in Exp. I.n Exp. I.

In Exp. II, the learning procedure was similar to tIn Exp. II, the learning procedure was similar to that of Exp. I. Then subjects were asked to classifhat of Exp. I. Then subjects were asked to classify patterns into one of the four categories they hy patterns into one of the four categories they had learned during the first step. ad learned during the first step.

Experiment IIExperiment II►Results:Results:

Once again, Ss who had been trained with Once again, Ss who had been trained with the high variability patterns did better in the the high variability patterns did better in the second step.second step.

Conclusion of Exp I, IIConclusion of Exp I, II

►The result of the first 2 Exp. favors the hypThe result of the first 2 Exp. favors the hypnoses that it is not the prototype alone thnoses that it is not the prototype alone that being stored.at being stored.

► It also indicates that Ss are learning someIt also indicates that Ss are learning something about the individual patterns.thing about the individual patterns.

Posner and Keele’s ExperimenPosner and Keele’s Experimentsts

►Experiment IIIExperiment IIIThe purpose of this Exp. is to judge directly whetThe purpose of this Exp. is to judge directly whether Ss are also learning information about the prher Ss are also learning information about the prototype.ototype.

In Exp. III, all Ss learned the large distortion versiIn Exp. III, all Ss learned the large distortion version. They were then asked to classify the followinon. They were then asked to classify the following patterns: old distortion they just learned, the pg patterns: old distortion they just learned, the prototype of the old distortion, and control patterrototype of the old distortion, and control patterns at varying distances from the old patterns.ns at varying distances from the old patterns.

Experiment IIIExperiment III►Results:Results:

Old distortions, schema, and new Level 5 Old distortions, schema, and new Level 5 patterns have nearly identical mean patterns have nearly identical mean distances from the memorized patterns, but distances from the memorized patterns, but the old distortions and schema are better the old distortions and schema are better recognized than the Level 5s and are not recognized than the Level 5s and are not different from each other.different from each other.

General ConclusionsGeneral Conclusions

►The prototype (schema) is more easily claThe prototype (schema) is more easily classified than other new patterns which are ssified than other new patterns which are also within the learned category.also within the learned category.

►The Exp. I and II suggests against the hypoThe Exp. I and II suggests against the hypothesis that only abstracted prototype is stthesis that only abstracted prototype is stored. Instead, variability shows its importored. Instead, variability shows its importance in the training process.ance in the training process.

Time of AbstractionTime of Abstraction

►When does the abstraction take place?When does the abstraction take place?

►During the learning task?During the learning task?

►When the Schema patter is first When the Schema patter is first shown?shown?

What is AbstractedWhat is Abstracted

►Mental image?Mental image?►Verbal description?Verbal description?

ThankThanks!s!

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