Chapter 4: Sensory & Primary Memory PowerPoint by Glenn E. Meyer, Trinity University ©2004 Prentice Hall Cognition – 2/e Dr. Daniel B. Willingham

2 What is Sensory Memory? Early Span of Apprehension Studies Early Span of Apprehension Studies Early Span of Apprehension Studies Early Span of Apprehension Studies Sperling’s Partial Report Procedure Sperling’s Partial Report Procedure Sperling’s Partial Report Procedure Sperling’s Partial Report Procedure Characteristics of Iconic Memory Characteristics of Iconic Memory Characteristics of Iconic Memory Characteristics of Iconic Memory What is Iconic Memory For? What is Iconic Memory For? What is Iconic Memory For? What is Iconic Memory For? Echoic Memory Echoic Memory Echoic Memory Echoic Memory ©2004 Prentice Hall

3 Early Span of Apprehension Studies Span of apprehension: The amount of information that can enter consciousness at once. Span of apprehension: The amount of information that can enter consciousness at once. Early Studies: Early Studies:  Jevons (1871) – counted beans thrown into a small box. Accuracy was usually perfect at < 4 beans. 95% at 5 beans. Declined above that as seen in Fig Using 50% criteria, span of apprehension = 9 beans.  Point made by others that subjects could perceive seeing more than they could report – Glanville and Dallenbach (1929), Woodworth (1938)  Lead to Sperling’s work ©2004 Prentice Hall

4 Sperling’s Partial Report Procedure Developed by Sperling (1960) to examine iconic memory Developed by Sperling (1960) to examine iconic memory Participants are shown an array of stimuli (usually letters or numbers) very briefly. Array can contain 4 to 12 items Participants are shown an array of stimuli (usually letters or numbers) very briefly. Array can contain 4 to 12 items They are given a cue (visual or auditory) telling them which subset of the stimuli to report. This is the Partial Report They are given a cue (visual or auditory) telling them which subset of the stimuli to report. This is the Partial Report The cue delay can vary. Since subjects don’t know which items will be cued, the percent of the subset reported estimates the percent of items available at a given time after the cue The cue delay can vary. Since subjects don’t know which items will be cued, the percent of the subset reported estimates the percent of items available at a given time after the cue This method showed that participants perceive most of the stimuli in a complex array. This method showed that participants perceive most of the stimuli in a complex array. Sperling argued the items held in a large capacity iconic memory Sperling argued the items held in a large capacity iconic memory ©2004 Prentice Hall A Q 6 8 T P W 1 2 Y 6 L Typical Sperling Display Immediate Report – 4 correct – 33% of array Immediate Cue of Row -3 correct – implying 75% of array available

5 Characteristics of Iconic Memory Large Capacity Large Capacity  Up to 17 letters, 2 seconds  Depends on stimulus conditions – dark fields enhance, bright pre and post fields cut down duration Spontaneous Decay and Potential to be Erased Spontaneous Decay and Potential to be Erased  Loss of info due to spontaneous decay  Decay begins at onset of target, not offset (DiLollo, 1980) as seen in Fig 4.3.  Information can also be lost due to a following stimulus acting as a mask (Breitmeyer & Ganz, 1976; Turvey, 1973) Brief Duration – 500 milliseconds to 1 second typically Brief Duration – 500 milliseconds to 1 second typically Representation – Initially thought to be a physical representation as selection of items on physical characteristics (ex. color) possible but not on semantic characteristics (digits vs. letters) (Sperling, 1960). This has been challenged and there may be some semantic info in iconic memory Representation – Initially thought to be a physical representation as selection of items on physical characteristics (ex. color) possible but not on semantic characteristics (digits vs. letters) (Sperling, 1960). This has been challenged and there may be some semantic info in iconic memory ©2004 Prentice Hall

6 What is Iconic Memory For? Haber (1983) argues against Iconic Memory as a useful concept Haber (1983) argues against Iconic Memory as a useful concept  Icon supposed to maintain stable image of the world through eye movements – Not supported by Irwin et al. (1983) as seen in Fig. 4.4 where iconic information not useful in integrating across saccades (rapid eye movements)  Haber suggests the only thing the icon would be useful for is trying to read at night during a thunder storm Loftus (1983) argues that the iconic experimental paradigm is a useful tool and the real world argument of Haber is not appropriate as in many sciences lab situations don’t mirror the real world but give us insights Loftus (1983) argues that the iconic experimental paradigm is a useful tool and the real world argument of Haber is not appropriate as in many sciences lab situations don’t mirror the real world but give us insights Iconic research has been robust and an important tool for examining the visual system and is still on-going. Iconic research has been robust and an important tool for examining the visual system and is still on-going. ©2004 Prentice Hall

7 Echoic Memory Auditory variety of sensory memory. Auditory variety of sensory memory. Experimental Evidence: Experimental Evidence:  Massaro (1970) – identification of a short tone was masked by a random auditory stimulus. If the tone was delayed identification improved. Echoic memory duration was estimated to be 250 milliseconds  Efron (1970a) – estimated echoic duration of 30 ms tone to be 130 ms Neural Representation: Neural Representation:  Lu, et al. (1992) – Echoic memory is the lifetime of neural activity in auditory sensory cortex by measuring activity with magnetoencephalography as seen in Box 4- 2 ©2004 Prentice Hall

8 What are the Characteristics of Primary Memory? Impetus to Study Primary Memory Impetus to Study Primary Memory How Forgetting Occurs How Forgetting OccursHow Forgetting OccursHow Forgetting Occurs Representation RepresentationRepresentation Capacity CapacityCapacity ©2004 Prentice Hall

9 Impetus to Study Primary Memory Broadbent (1958) likened mind to an electronic information processing system. Flow of information was: Broadbent (1958) likened mind to an electronic information processing system. Flow of information was:  Large capacity sensory memory  Filter  Primary memory – associated with consciousness and fades if not rehearsed Miller (1956) Miller (1956)  Reviewed literature suggesting what became known as the magic number 7+ 2 – the limited capacity of primary memory  Suggested the process of chunking : A unit of knowledge that can be decomposed into smaller units of knowledge. Similarly, smaller units of knowledge can be combined (“chunked”) into a single unit of knowledge (e.g., chunking the numbers 1, 9, 0, and 0 into a unit to represent the year 1900). This is a way to get around the primary memory limit above Brown (1958) and Peterson & Peterson (1959) demonstrated the difference between primary and secondary memory by suggesting the forgetting processes of primary memory was decay and not interference. Brown (1958) and Peterson & Peterson (1959) demonstrated the difference between primary and secondary memory by suggesting the forgetting processes of primary memory was decay and not interference.  Had subjects learn a trigram (ex. TPW) and then count backwards by threes from a large number  Plotted percent correct recall as time of counting varied  As seen in Fig 4.5,recall was very low by 18 seconds, suggesting decay of primary memory ©2004 Prentice Hall

10 How Forgetting Occurs Two types of interference also contribute to forgetting: Two types of interference also contribute to forgetting:  Proactive Interference - Earlier learning interferes with new learning.  Retroactive Interference - Later learning interferes with earlier learning  Keppel and Underwood (1962) demonstrated in the Brown-Peterson & Peterson task that repeated trials produced more forgetting of the target – suggesting a role for proactive interference in primary memory  Reitman (1971) – varied type of activity during the delay period in Brown- P&P and found matching types of activity to the target type increased forgetting, demonstrated the role of retroactive interference in primary memory Decay Again Decay Again  Baddeley and Scott (1971) demonstrated decay on one trial as seen in Fig 4.8 when there is no chance for proactive interference  Researchers suggest decay necessary or interference would overwhelm the system. Altmann and Gray (2002) demonstrate such in a rule based categorization task as seen in Fig ©2004 Prentice Hall

11 Representation Material in Primary Memory Can Be Coded: Material in Primary Memory Can Be Coded:  Visuospatially  Acoustically  Semantically  Perhaps also with a tactile representation Early Research Suggested Primary Memory Was Solely Acoustic Early Research Suggested Primary Memory Was Solely Acoustic  Baddeley (1966) found primary tasks hurt if all items sounded similar (ex. Mad, man, mat, cap, cad, can,cat)  Conrad (1964) demonstrated acoustic confusion errors in primary memory: Errors in primary memory based on sound (e.g., thinking one heard g instead of d). The presence of such errors indicates that participants use an acoustic code in primary memory on the task. For example, they might mistake an “M” for “N” when they hear it. ©2004 Prentice Hall

12 Representation - Continued Spatial Information in Primary Memory: Spatial Information in Primary Memory:  Baddeley, et al. (1975) reports a secondary tracking task interfered with subjects remembering a visuospatial instruction set for imagining a matrix. The secondary task did not interfere with a nonvisual task Semantic Information in Primary Memory Semantic Information in Primary Memory  Demonstrated by Release from Proactive Interference  Refers to the effect in which proactive interference dissipates if one changes the stimulus materials.  Experimental test  Uses Brown-Peterson paradigm with repeated trials. Target words are used instead of trigrams  There are up to 5 trials with the first trials semantically related, the last item wasn’t (for example: trial 1 = apple, 2 = orange, 3 = pear, 4 = doctor)  Recall declined over the first 3 trials (Proactive Interference) but the recall of the last item was significantly increased ( release from PI), indicating that semantic context was present in primary memory ©2004 Prentice Hall

13 Capacity Miller (1956) - magic number 7 + 2, also known as digit span at turn of the century (1900’s) Miller (1956) - magic number 7 + 2, also known as digit span at turn of the century (1900’s) Capacity of Different Primary Memory codes Capacity of Different Primary Memory codes  Acoustic code best described as the number of items you can say in two seconds as found in the word length effect (Baddeley, et al. 1975). Subjects can remember more short than long words.  Semantic code best described by chunks - Simon (1974) - as seen in Fig. 4.11, subjects can remember more total words if organized into semantically related chunks - but chunk number in primary member seems fairly constant  Visuospatial code about 4 objects (Luck and Vogel, 1997; Lee and Chun, 2001). For example, which is easier to remember? The object on the left or its 9 component lines on the right? ©2004 Prentice Hall

14 How does Primary Memory Work? Models of Primary Memory Models of Primary Memory Models of Primary Memory Models of Primary Memory Working Memory Working Memory Working Memory Working Memory Primary Memory Contributions to Secondary Memory Tasks Primary Memory Contributions to Secondary Memory Tasks Primary Memory Contributions to Secondary Memory Tasks Primary Memory Contributions to Secondary Memory Tasks Working Memory as a Workspace Working Memory as a Workspace Working Memory as a Workspace Working Memory as a Workspace ©2004 Prentice Hall

15 Models of Primary Memory Modal Memory (Murdock, 1974) based on sensory, short- term and long-term systems as seen in Fig Modal Memory (Murdock, 1974) based on sensory, short- term and long-term systems as seen in Fig  Attended info from Sensory Memory moves into Short Term Memory  Information remains in Short Term Memory for 30 seconds unless rehearsed  More processing in STM leads to information being sent to Long Term Memory  Information can also enter Short Term Memory from Long Term Memory  Information can be forgotten from Sensory Memory and Short Term Memory through decay. Long Term Memory loss due to interference  Model now seen as inadequate for several reasons. ©2004 Prentice Hall

16 Working Memory - Baddeley, 1986 Secondary Memory & Sensory Memory - slaves to Central Executive, not shown Secondary Memory & Sensory Memory - slaves to Central Executive, not shown Phonological Loop: The part of the working memory model in which auditory information is stored. It has two components: Phonological Loop: The part of the working memory model in which auditory information is stored. It has two components:  Phonological store: The part of the phonological loop that can store about 2 s of auditory information.  Articulatory Control Processes: The process that allows one to enter information into the phonological store; it is literally the process of talking to yourself.  Evidence for the Phonological loop comes from Articulatory Suppression studies: Refers to demanding that participants keep the articulatory system busy with nonsense during encoding (usually by saying “thethethethe” or something similar), thereby ensuring that they will not code stimuli in the phonological store.  Speech can gain access to the Articulatory Store through obligatory access which refers to the fact that verbal information (but not all sounds) appear to be entered into the phonological loop by its mere presence, even if the participant does not want it to enter. ©2004 Prentice Hall Phonological Loop LoopCentralExecutive VisuospatialSketchpad

17 Working Memory - Continued Visuospatial sketchpad is the visual analog of the phonological loop. Conceived as a buffer on which visual or spatial information can be manipulated and briefly stored. It is thought to be similar to visual imagery. Visuospatial sketchpad is the visual analog of the phonological loop. Conceived as a buffer on which visual or spatial information can be manipulated and briefly stored. It is thought to be similar to visual imagery.  Spatial Information (where things are) and visual information (what they look like) are separable according to Baddeley (as seen in Baddeley and Lieberman (1980) Central Executive - Baddeley suggests Norman and Shallice’s (1986) model of attention is a good starting place for the central executive. The model is seen in Figure Model has two important selection processes: Central Executive - Baddeley suggests Norman and Shallice’s (1986) model of attention is a good starting place for the central executive. The model is seen in Figure Model has two important selection processes:  Contention Scheduling:The process by which the relative importance of two tasks is weighed if executing the tasks simultaneously is not possible.  Supervisory Attentional System:The SAS selects action when a task must be planned in advance; when automatic processes appear to be having negative or unexpected consequences; when a new, unfamiliar action must be taken or ; when or a strong habit must be suppressed. Model is supported by: Model is supported by:  Baddeley (1966) - subjects unable to produce random letter strings as speed increased as the SAS couldn’t keep up  Neural imaging - MacDonald et al. (2000) using modified Stroop task found evidence for control processes in the dorsolateral frontal cortex and monitoring in the anterior cingulate cortex ©2004 Prentice Hall

18 Primary Memory Contributions to Secondary Memory Tasks ©2004 Prentice Hall First Last Position in the List % Recall Primacy Recency Serial Position Effect Serial position: The position of a word (or other stimulus) in a list, usually of to-be-remembered stimuli. Recency effect: Refers to the fact that memory for items at the end of a list is quite good in a task demanding immediate free recall. Thought to be due to retrieval from Primary Memory. Primacy Effect: Refers to the fact that memory for items at the beginning of a list is good (relative to that for items in the middle of the list). Thought to be due to first words being more likely to enter secondary memory. Serial Position Effect Serial position: The position of a word (or other stimulus) in a list, usually of to-be-remembered stimuli. Recency effect: Refers to the fact that memory for items at the end of a list is quite good in a task demanding immediate free recall. Thought to be due to retrieval from Primary Memory. Primacy Effect: Refers to the fact that memory for items at the beginning of a list is good (relative to that for items in the middle of the list). Thought to be due to first words being more likely to enter secondary memory. Experimental Evidence Glanzer and Cunitz (1966) Delay of recall weakens Recency as primary memory had supposedly faded as seen in Fig Increasing time between items enhances primacy as more time given for item rehearsal and entry into secondary memoryExperimental Evidence Glanzer and Cunitz (1966) Delay of recall weakens Recency as primary memory had supposedly faded as seen in Fig Increasing time between items enhances primacy as more time given for item rehearsal and entry into secondary memory

19 Working Memory as a Workspace Phonological Loop: Important in acquiring new vocabulary (Baddeley, Gathercole, & Papagno, 1998): In children digit span (measure of phonological loop) positively correlates with vocabulary size Phonological Loop: Important in acquiring new vocabulary (Baddeley, Gathercole, & Papagno, 1998): In children digit span (measure of phonological loop) positively correlates with vocabulary size Daneman & Carpenter (1980): Working memory span is good predictor of reading comprehension in college students Daneman & Carpenter (1980): Working memory span is good predictor of reading comprehension in college students Working memory span is good predictor of performance on reasoning tasks and may be seen in age related deficits (Salthouse, 1992) Working memory span is good predictor of performance on reasoning tasks and may be seen in age related deficits (Salthouse, 1992) ©2004 Prentice Hall

20 Neurological Findings of Interest Counting and Subitizing: The latter is process for recognizing the number of items in a display in an effortless manner. It usually can be done for a set of 1 to 4 items. Piazza, et al. (2002) found that counting and subitizing had similar patterns of cortical activation (see Box 4-1) using PET scans. Counting and Subitizing: The latter is process for recognizing the number of items in a display in an effortless manner. It usually can be done for a set of 1 to 4 items. Piazza, et al. (2002) found that counting and subitizing had similar patterns of cortical activation (see Box 4-1) using PET scans. Brain Components of the Phonological Store: Paulseu, et al. (1993) attempted to localized the two components of the phonological loop – 1) phonological store and 2) the articulatory control process. As seen in Box 4-3 some patients indicate separation of processes. Ventrolateral prefrontal cortex (Broca’s area) critical for the maintenance of phonological material Brain Components of the Phonological Store: Paulseu, et al. (1993) attempted to localized the two components of the phonological loop – 1) phonological store and 2) the articulatory control process. As seen in Box 4-3 some patients indicate separation of processes. Ventrolateral prefrontal cortex (Broca’s area) critical for the maintenance of phonological material Brain Basis of the Central Executive: Dorsolateral prefrontal cortex – manipulation of phonological material Brain Basis of the Central Executive: Dorsolateral prefrontal cortex – manipulation of phonological material  Petrides (1989)  D’Esposito, et al. (1999, 2000) – concludes ventrolateral prefrontal cortex contributes to maintenance, dorsolateral to manipulation. Not clear if the latter contributes to maintenance. ©2004 Prentice Hall