Chapter FiveChapter Five

The Cognitive Approach II: The Cognitive Approach II: Memory, Imagery, and Problem Memory, Imagery, and Problem

SolvingSolving

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MemoryMemory

• MemoryMemory is the capacity to retain information is the capacity to retain information over time.over time.

• Memory allows us to learn from previous Memory allows us to learn from previous experiences.experiences.

• Memory systems can be characterized by Memory systems can be characterized by duration, capacity, and coding.duration, capacity, and coding.

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Sensory memorySensory memory

• Information from the different sensory Information from the different sensory modalities is stored in separate sensory modalities is stored in separate sensory memories.memories.

• Iconic memoryIconic memory is a is a visual sensory store with visual sensory store with a short duration of less than one second.a short duration of less than one second.

• Echoic memoryEchoic memory is an auditory sensory store is an auditory sensory store with a duration several seconds long.with a duration several seconds long.

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Sensory memorySensory memory

• Sperling (1960) presented letter arrays.Sperling (1960) presented letter arrays.

R G C PL X N FS B J Q

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Sensory memorySensory memory

• In the In the whole report conditionwhole report condition, participants attempted to recall , participants attempted to recall the entire array but could only remember several letters.the entire array but could only remember several letters.

• In the In the partial-report conditionpartial-report condition, they were cued after the , they were cued after the display to report the letters in one row only. They could display to report the letters in one row only. They could remember all the letters.remember all the letters.

• This shows iconic memory has a high capacity, capable of This shows iconic memory has a high capacity, capable of storing most of the information seen in the visual field.storing most of the information seen in the visual field.• How does it show this, if subjects could only report one row of letters?How does it show this, if subjects could only report one row of letters?

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• Sometimes also called Sometimes also called short-term memoryshort-term memory..• Has a limited capacity. Can only hold a Has a limited capacity. Can only hold a

small number of items.small number of items.• Capacity can be increased by grouping Capacity can be increased by grouping

items into meaningful wholes called items into meaningful wholes called chunkschunks. . Limit is about 7±2 chunks.Limit is about 7±2 chunks.

Working memoryWorking memory

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Effects of ChunkingEffects of Chunking

N F L C B S I R A M T VN F L C B S I R A M T V

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• Has a limited duration. Information can decay in Has a limited duration. Information can decay in seconds.seconds.

• Duration can be increased by repeating items, a Duration can be increased by repeating items, a process called process called rehearsalrehearsal..

Working memoryWorking memory

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Working memory durationWorking memory duration

Peterson and Peterson (1959).

(Permits rehearsal)

(Prevents rehearsal)

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• Coding can be acoustic, visual, or semantic.Coding can be acoustic, visual, or semantic.• Visually presented lettersVisually presented letters

• Participants confuse “A” & “K”; “E” & “P”Participants confuse “A” & “K”; “E” & “P”

• Mental rotation time to compare patterns.Mental rotation time to compare patterns.• More proactive interference of “apple” with “orange” More proactive interference of “apple” with “orange”

than with “tulip”.than with “tulip”.

Working memoryWorking memory

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Long-term memoryLong-term memory

• Consists of several distinct subtypes.Consists of several distinct subtypes.• Implicit or Implicit or procedural memoryprocedural memory holds holds

knowledge for skills such as riding aknowledge for skills such as riding a bicycle. It is demonstrated by doing and occurs without conscious recall.

• Explicit or declarative memory holds memory for facts and events. It is demonstrated by saying and occurs with conscious recall.

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Declarative memoryDeclarative memory

• Declarative long-term memory consists of two Declarative long-term memory consists of two types.types.

• Semantic memorySemantic memory contains factual knowledge and contains factual knowledge and can be organized hierarchically. Example: George can be organized hierarchically. Example: George Washington was the first president of the United Washington was the first president of the United States.States.

• Episodic memoryEpisodic memory contains personally experienced contains personally experienced events and is organized temporally or spatially. events and is organized temporally or spatially. Example: What you did on your last birthday.Example: What you did on your last birthday.

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Semantic memory durationSemantic memory duration

Bahrick (1984).

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The modal memory modelThe modal memory model

• Formulated by Formulated by Atkinson and Atkinson and Shiffrin (1971).Shiffrin (1971).

• Shows how Shows how information is information is transferred transferred between the major between the major memory types.memory types.

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The ACT* memory modelThe ACT* memory model

Anderson (1983, 1990)

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The working memory modelThe working memory model• From Baddeley From Baddeley

(1986, 1992).(1986, 1992).• Shows interactions Shows interactions

between between components of components of working memory.working memory.

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Visual imageryVisual imagery

• A visual image is a mental representation of A visual image is a mental representation of an object or scene that preserves metric an object or scene that preserves metric spatial information.spatial information.

• Images are constructed internally from Images are constructed internally from information in memory.information in memory.

• Imagery and perception utilize the same Imagery and perception utilize the same neural machinery.neural machinery.• Images interfere with perception [Kosslyn]Images interfere with perception [Kosslyn]

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The Kosslyn-Schwartz theory of The Kosslyn-Schwartz theory of visual imageryvisual imagery

• A A surface representationsurface representation of an image is of an image is quasi-pictorial and occurs in a spatial quasi-pictorial and occurs in a spatial medium.medium.• Think of an elephant.Think of an elephant.

• A A deep representationdeep representation consists of the consists of the information in long-term memory used to information in long-term memory used to generate the surface representation.generate the surface representation.

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Image processesImage processes

• Image generationImage generation refers to the formation or refers to the formation or construction of an image. Examples: part construction of an image. Examples: part placement and resizing.placement and resizing.

• Image inspectionImage inspection is reading off the image to is reading off the image to extract information. Examples: scanning, zooming, extract information. Examples: scanning, zooming, and panning.and panning.• How many windows are on the front of your building?How many windows are on the front of your building?

• Image transformationImage transformation is an operation that is is an operation that is applied to an image. Examples: rotation about applied to an image. Examples: rotation about different axes.different axes.

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Problem solvingProblem solving

• Transforming a given situation into a Transforming a given situation into a desired situation or goal.desired situation or goal.

• Characteristics of problem solving:Characteristics of problem solving:1.1. Goal directednessGoal directedness

2.2. Sequence of operationsSequence of operations

3.3. Cognitive operationsCognitive operations

4.4. Subgoal decompositionSubgoal decomposition

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The problem spaceThe problem space• Represents possible steps toward solving the Represents possible steps toward solving the

problem.problem.• States are nodes. Operators that transform a state States are nodes. Operators that transform a state

produce paths to other states.produce paths to other states.

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The Tower of HanoiThe Tower of Hanoi

• Get all the discs onto peg 3 in the same order.Get all the discs onto peg 3 in the same order.• Move only one disc at a time.Move only one disc at a time.• Can only place a smaller disc on top of a larger Can only place a smaller disc on top of a larger

one.one.

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TofH As State SpaceTofH As State Space

∂

∂ ∂

∂ ∂

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TofH As Problem Reduction SpaceTofH As Problem Reduction Space

∂

∂ ∂

∂

∂

∂∂

∂

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TofH As Problem Reduction SpaceTofH As Problem Reduction Space

∂

∂ ∂

∂

∂

∂∂

∂

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A block-world problemA block-world problem

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The SOAR modelThe SOAR model

• An example of a cognitive architecture used to An example of a cognitive architecture used to solve problems (Newell, 1991).solve problems (Newell, 1991).

• Knowledge in LTM selects operators and guides Knowledge in LTM selects operators and guides search through the problem space.search through the problem space.

• Goes through a decision cycle based on acquiring Goes through a decision cycle based on acquiring evidence andevidence and then executing a decision.then executing a decision.

• Operators can be selected based on preferences.Operators can be selected based on preferences.• Can create novel subgoals when unable to Can create novel subgoals when unable to

proceed further.proceed further.

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How SOAR might solve a block-How SOAR might solve a block-world problemworld problem