PSY 445: Learning & Memory Chapter 7 - Human Memory: Conceptual Approaches

Memory Processes involved in retaining, retrieving, and using information about stimuli, images, events, ideas, and skills after the original information is no longer present Three theoretical approaches to memory Memory components Different types of memory Stages of memory Series of steps are involved in memory process Processes of memory Emphasis is on how memories are processed

Partitioning Memory Why do we think there are multiple memory systems? General principles differ for STM and LTM Heuristic value – guideline that is fairly accurate Empirical evidence supporting the existence of multiple processes Dissociation – occurs when an experimental variable has different effects on different tasks Double dissociation – experimental variables differentially affect performance on two or more tasks

Double Dissociation Kesner, Hopkins, & Chiba (1992) Procedure Group 1: Left-hemisphere brain damage Group 2: Right-hemisphere brain damage Words or an X was flashed on a screen Participants were asked to recall the word and the location of the X Results Group 1 did worse on the word-recognition test; Group 2 did worse on the spatial-location test Interpretation The two cerebral hemispheres are playing different roles in verbal and spatial learning; double dissociation

Components of Memory Approach Dual-Store Theory Short-Term Memory Long-term memory Atkinson & Shiffrin (1968)

Short-Term Memory (STM) Psychology 101 On Line Short-Term Memory (STM) A limited capacity memory system involved in the retention of information for brief periods; it is also used to hold information retrieved from long-term memory for temporary use Duration of STM Without maintenance rehearsal something stays in STM for between 15-30 seconds Capacity of STM About 7 items

STM vs. LTM Differences in capacity STM is relatively small and easily measured LTM is immeasurable and probably limitless Differences in duration STM can hold only items briefly LTM are relatively permanent; not affected by the passage of time much Evidence for the STM vs. LTM Distinction Serial-position curve results

Divisions of LTM Explicit memory Is long-term memory for factual knowledge and personal experiences and requires conscious recall Two types of explicit memories: Episodic memories are memories for personal life experiences (e.g., your senior prom night) Semantic memories are memories for factual knowledge that is true of everyone (e.g., the current President of the United States)

Divisions of LTM Testing Episodic and Semantic Memories Limitations It is difficult to differentiate episodic and semantic memories in lab tests The two forms of memory require different testing materials, procedures, or tasks Word-frequency effect is an example of this See next slide 

Neely (1989) Procedure Group 1: given a test of episodic memory High-frequency and low frequency words are presented to participants; later, word recognition test Group 2: given a test of semantic memory High-frequency and low frequency words are presented to participants; later strings of letters are briefly flashed on the screen; task is to decide which strings form real words and which do not

Neely (1989) Results Group 1: More low-frequency words from original list are recognized; this paradoxical result is referred to as the Word-Frequency Effect Group 2: More high-frequency words from original list are recognized Interpretation Confounding of the type of test with the type of memory Not necessarily testing episodic vs. semantic processes but rather recognition memory vs. identification memory

Divisions of LTM Implicit memory Long-term memory that influences our behavior, but does not require conscious awareness or declarative statements (e.g., for most adults, driving a car; walking) Procedural memory is a type of implicit memory See next slide 

Procedural Learning The acquisition of knowledge of how to do things and includes perceptual skills, motor skills, and cognitive skills Memory for highly practiced skills (often referred to as skill memory) Bike-riding, Shoe-tying Automatic or implicit nature to it (implicit memory) Do you think about reading a book? Do you think about riding your bike? Mirror drawing 

Repetition Priming The facilitated response to a stimulus that has been recently experienced Occurs when the test stimulus is the same as or resembles the priming stimulus The initial presentation of a stimulus affects subsequent presentations

Repetition Priming Rajaram & Roediger (1993) Procedure Word completion test Phase 1: Present priming stimuli Example: table Phase 2: Open-ended recall Example: Complete this word: tab___ Results Primed participants (49%) are more likely than non-primed participants (30%) to use a particular word Interpretation Participants responses are manipulated by implicit processes

Divisions of LTM: Visual Object Priming Warrington & Weiskrantz (1968) Procedure Participants are patients with Korsakoff’s syndrome (cannot form new LTMs); Researchers trained them to identify incomplete pictures Subjects never remembered their previous days of training

Divisions of LTM: Visual Object Priming Results Performance improves even though the person does not remember being trained Interpretation Priming can occur with pictorial stimuli as well; previous experiences affect current behavior without awareness Warrington & Weiskrantz (1968) Results

Stages of Memory Theory: Series of steps are involved in memory process 3 stages of processing for manipulation of mental representations: Encoding (acquisition of info) Storage (retention of info) Retrieval (recovery of info) Encoding/Failure Retrieval? (LTM) STM  Retention time

Stages of Memory Dissociating Stages Experimental Neuropsychological

Experimental Dissociations Experimental manipulations often detect functional dissociations of the stages Encoding, storage, or retrieval may be affected differently Different things are involved depending on the stage of memory

Experimental Dissociations Storm & Caird (1967): Experiment 1 Procedure Alcoholic inpatients were given lists to learn either while sober or after consuming alcohol; both groups tested later in sober state (two groups: S/S, A/S) Results S/S outperforms A/S Interpretation Alcohol impaired encoding However, alternative explanation is performance is related to state-dependent retrieval

Experimental Dissociations Storm & Caird (1967): Experiment 2 Procedure Two more groups were added (total of four groups now) Studied sober and tested when drinking alcohol (S/A) Studied when drinking alcohol and tested while drinking alcohol (A/A) Results S/S > A/A Interpretation More than just retrieval failure; due to impaired encoding

Neuropsychological Dissociations Neuropsychologists attempt to dissociate certain stages by finding individuals with impairment at one stage or another Hippocampus: brain structure plays a key role in allowing us to store new information The classic case of H.M. who had this part of brain removed In 2008 (at the time of his death at age 82), was his name revealed as Henry Molaison 

Neuropsychological Dissociations From neuropsychological dissociation view, H.M.’s problem could be explained in several ways: Encoding deficit Storage deficit (encoding okay) Retrieval deficit (encoding and storage okay)

Processing Approaches: Depth of Processing Craik & Lockhart (1972) A single memory system is hypothesized Rapid forgetting is due not to a loss from transient STM but rather because of shallow processing Retention is due not to transfer from one memory store to another, but rather to deeper processing

Storage How does storage of information take place? Maintenance Rehearsal Repeating things over and over Spacing effect Elaborate Rehearsal Involves thinking about how new material relates to information already stored in memory

Depth of Processing Shallow Processing Deep Processing Little attention to meaning Focus on physical features of the word (number of vowels, letters in all capitals) Occurs during maintenance rehearsal Deep Processing Close attention to meaning Relating item to something else

Experimental Evidence for DOP Craik & Tulving (1975) Procedure Recall Test was a surprise to participants

Experimental Evidence for DOP Procedure Types of questions Shallow: Is the word printed in capital letters? Deeper: Does the word rhyme with train? Deepest: Does the word fit into the sentence “He saw a ____ on the street?”

Experimental Evidence for DOP Results Craik & Tulving (1975) Shallow: Deeper: Deepest: Deep processing takes longer but results in better memory

What DOP tells us? Interpretation Memory for words is better when they are linked to other knowledge Craik & Tulving (1975)

Depth of Processing: Limitations Depletion of Memory Capacity When participants are attempting to perform two cognitive tasks at once, (for example, doing math calculations and remembering words), if the primary task requires deeper processing, this leaves little left over for the other task Deeper processing on the first task is shown by poor performance on the second task Semantics Issue The term “depth” appears to be taking on different meanings Elaboration of an item in memory or more distinctive representation in memory

Processing Approaches: Transfer Appropriate Processing Morris, Bransford, & Franks (1977) Similarity between encoding and retrieval conditions During retrieval, we need to reinstate the cognitive operations that were used at encoding Explicit memory: match mental operations of encoding and retrieval Implicit memory: match perceptual operations at encoding and retrieval

Processing Approaches: Transfer Appropriate Processing Weldon & Roediger (1987) Procedure Phase 1:Students studied lists of both pictures and words Phase 2: Either a picture fragment or word-completion test was given Task for both groups was to name the picture or word

Processing Approaches: Transfer Appropriate Processing Weldon & Roediger (1987) Results Studying pictures produced more priming than did words on a picture-fragment test; studying words produced more priming than did pictures on the word-fragment test Results 

Processing Approaches: Transfer Appropriate Processing Interpretation Transfer-appropriate processing was necessary for optimal recall to occur Picture-fragment test: inspecting a picture is similar at both encoding and at retrieval; dissimilar to word-reading Word-fragment test: Reading words is a cognitive operation similar to completing words, but inspecting pictures is not

Connectionist Models Simulate various memory phenomenon by using a network of hypothetical neurons Attempt to statistically model the nervous system on a computer Each neural unit can potentially have connections to many other units; the more connections the better memory

Connectionist Models Modeling Person Identification Many possible connection between names and identities For example, John has a connection to several potential features 

Connectionist Models The Delta Rule Connections can vary in strength Mathematical formula used for increases and decreases in strength

The Study of Abnormal Memory: Amnesia Classification of Amnesias Two dimensions Cause: physical or psychological (psychogenic amnesia) Time: loss of memory preceding (retrograde) or following the trauma (anterograde) Retrograde amnesia Loss of memory for events that have happened prior to trauma or disease Anterograde amnesia The inability to form long-term memories for events following brain surgery or trauma  Retrograde amnesia—TRAUMA—Anterograde amnesia

Types of Amnesias Amnesias caused by psychological traumas are almost retrograde Psychogenic Amnesia 3 main categories: Limited Amnesia Forgetting of a specific traumatic experience Fugue state Loss of one’s entire past life and identity; often travel away from home Dissociation Disorder A person exhibits multiple personalities or identities

Everyday Forgetting ABC News Poll (1997) 46% more worried about failing memory than failing health Plethora of self-help books, websites, and herbal medications Most worry is unjustified

Credits Some of the slides in this presentation prepared with the assistance of the following website: www.csupomona.edu/.../PSY335%20PPTs/Baddeley/BChap6....