Memory Span and Updating in Working Memory Independent or inter-related processes?
Gidon T. Frischkorn, Anna-Lena Schubert, Jan Rummel & Dirk Hagemann
Contact:
Heidelberg University
[email protected]
Theoretical Background
Experimental Paradigm
I. Cognitive Processes in Working Memory (WM)
F
No Updating
0.5 s 1s
1s 0.5 s 1s Updating
G
0.5 s 1s 1.5 s
S
(Barrouillet, Bernardin & Camos, 2004) • Memory traces are activated in WM • The activation for a specific memory trace decays over time • Decay can be counteracted by refreshing • Processing of information and storage rely on the same cognitive resource (i.e. attention) • Lower activation of a memory trace results in lower recall probabilities for a memory item Overload and additional processing demands (e.g. Updating) impair refreshing of memory traces and lead to forgetting in WM
• In Updating trials two new letters were presented at two randomly selected positions • Participants had to remove the initially encoded letters at these positions and remeber the newly presented letters • In No Updating trials participants only saw the empty boxes for the same time as in Updating trials
0.5 s
task focus
R
until reaction max 3s 0.5 s
?
0.5 s
F
until reaction max 3s 0.5 s until reaction max 3s
• The probe letter was a completely new letter not presented within the respective trial (No Interference) • The probe letter was a to remembered letter from another position (Memory Set Interference) • Only in Updating Trials: The Probe letter was the initially encoded letter that had to be removed during updating (Updating Interference)
• Match: matched vs. non-matched retrievals • In non-matched retrievals: No Interference - Memory Set Interference - Updating Interference • Position Updated: Position was updated vs. was not updated
Dependent Variables:
• Mean Reaction Times • Percent Correct • Parameters of the drift diffusion model
time in seconds
10
recall probability
ME Pos. Upd.: BFIncl.= 0.2
HDI Pos.Upd.: [-.25; .25]
ME Int. (NoUp.): BFIncl.= 6.7 · 105 ME Int. (Upd.): BFIncl.= 6.9 · 103
ME Int. (NoUp.): BFIncl.= 69.6 ME Int. (Upd.): BFIncl.= 38.6
HDI Updating: [-.43; .06] HDI Mem. Int.: [-.86; -.37] HDI Upd. Int.: [-.72; -.06]
1. Storage and Processing in Working Memory are functionally related and may rely on similar cognitive processes limiting WMC 2. The drift rate of a decision processes during memory retrieval may underlie the accuracy of representation and the speed of memory retrieval.
2
3
1
2
3
4
1
2 4
3
3. Information from other Positions in Memory or Information that is no longer relevant (i.e. updated) interferes with other Information in WM
5
0.25
8
ME Pos. Upd.: BFIncl.= 0.9
Take Home Messages:
Procedure:
1
0.5
6
HDI SetSize: [-.49; -.17] HDI Updating.: [-.33; .23] HDI Interaction: [-.42; .02]
Retrieval Conditions:
0.75
4
ME SetSize: BFIncl.= 1.1 · e12 ME Updating: BFIncl.= 8.4 · e8 Interaction: BFIncl= 82.5
• Memory Set Size: 3 - 5 • Updating: No Updating - Updating in a Trial
1
2
ME SetSize: BFIncl.= ∞ ME Updating: BFIncl.= 18.9 Interaction: BFIncl= 3.2
• After a short cue (i.e. question mark) probe letters were presented in each box • The order of retrieval was random for each trial • Participants had to decide as quickly and accuractely as possible wether the probe letter matched the letter they remebered at the respective position • If the letter did not match the to be remembered letter, there were two or three additional conditions:
• 6 Practice Trial (one in each Set Size and Updating condition) • 114 experimental trials
0
(estimated in Hier. Drift Diff. Model)
Experimental Manipulations:
Decay
0
(Bayesian ANOVA)
Drift Rate
3. Retrieval Phase
?
G
Accuracies
2. Updating Phase
? 0.5 s
II. Limitations for Working Memory Capacity (WMC)
Context Cues with additional information (e.g. Updating) should have less accurate representations
H
(student sample; N = 39, 60.5% female)
• Random letters (consonants) appear serially in each of the 3 to 5 boxes • Each letter had to be encoded at the position it was presented • Each letter was only used once within each trial
1s 0.5 s
W
(Bayesian ANOVA)
1. Encoding Phase
1s
Are processing and storage in WM related or independent processes?
(Oberauer, Lewandowsky, Farrell, Jarrold & Greaves, 2012) • Information is stored in WM by binding content information to context cues • Context Cues as well as content information is represented by a unique set of distributed acitvations in a content or feature layer • Bindings, especially from close context cues, interfere with each other • Ambigous bindings lead to misreprensetations (e.g. transposition errors) in working memory
Mean Reaction Times
Trial Procedure
• WM is a cognitive system for storing and maintaining information for cognitive processing (Baddeley, 2003) • Current theories often distinguish between storage processes and attentional control mechanisms in WM (Baddeley, 2003) • The attentional control mechanisms, often called Executive Functions (EF), are needed for switching between tasks or modalities, updating information or separating relevant from irrelevant information (Miyake, Friedmann, Rettinger, Shah & Hegarty, 2001) • Correlational studies have shown strong relationships between EF, especially updating, and WM (McCabe, Roedinger III, McDaniel, Balota, Hambrick, 2010) • Experimental studies suggest that updating is independent from memory storage in WM (Ecker, Lewandowski & Oberauer, 2014)
Interference
Results
12
4. There is no clear evidence for decay in WM.
Positions of boxes on the screen in the three memory set sizes. Numbers in the boxes refer to the serial encoding in each trial.
References
Baddeley, A. (2003). Working Memory: Looking Back and Looking Forward. Nature Reviews Neuroscience, 4(10), 829-839. Barrouillet, P., Bernardin, S., & Camos, V. (2004). Time constraints and resource sharing in adults’ working memory spans. Journal of Experimental Psychology: General, 133(1), 83–100. Ecker, U. H., Lewandowsky, S., & Oberauer, K. (2014). Removal of information from working memory: A specific updating process. Journal Of Memory And Language, 7477-90. Miyake, A., Friedman, N. P., Rettinger, D. A., Shah, P., & Hegarty, M. (2001). How are visuospatial working memory, executive functioning, and spatial abilities related? A latent-variable analysis. Journal Of Experimental Psychology: General, 130(4), 621-640. Oberauer, K., Lewandowsky, S., Farrell, S., Jarrold, C., & Greaves, M. (2012). Modeling working memory: An interference model of complex span. Psychonomic Bulletin & Review, 19(5), 779-819.
