WM 3 - training effects Flashcards
brain training
- does it work?
- aim is to make brain bigger and stronger
- can use apps to help
–> but do they?
The N back task
- brain training task
- test of working memory
- remember the list of letters
–> is the presented letter the same as the letter two letters before
–> e.g. A J L = no
–> e.g. F H F = yes
Ericcson et al (1980) study
- after more than 230 hours of practice in the laboratory, a subject was able to increase his memory span from 7 to 79 digits
- with an appropriate mnemonic system, there is seemingly no limit to memory performance with practice
define transfer
improvements in a practiced task leads to improvements in unpracticed tasks
was the task specific in Ericcson’s et al (1980) study?
- in one experimental session, S.F. was switched from digits to letters of the alphabet after 3 months of practice and exhibited no transfer
- his memory span dropped back to about six consonants
strategy based training
- introduction and acquisition of strategies
–> e.g. a pneumonic to remember the name and order of planets - helpful for material-or-task specific tasks
- difficult to transfer to other contexts
process based training
- repeated practice of specific tasks targeting cognitive processes
–> e.g. daily practice of complex span tasks - assumed to transfer to other contexts
functional overlap between training and transfer
transfer is expected if practiced and non-practiced tasks share underlying processes
working memory as a core ability
- variation in working memory is correlated with variation in many other abilities
- by enhancing working memory, we might be able to improve a wide range of related cognitive abilities
success between training and transfer
- practise = working memory training tasks (N-back)
- near transfer = untrained working memory tasks (complex-span task)
- far transfer = different (but related) cognitive ability (e.g. reasoning)
how do we measure training effects?
- methodological rationale
- performance at a pretest (baseline) assessment is compared to performance at a post-test after training
–> e.g. you do all tasks (practise, near and far) before training, one task during training (practise) and then all tasks again post-test
how do we compare results in a methodological rationale?
- change is evaluated relative to a control group
–> passive group = no intervention
–> active group = alternative intervention
evaluate use of passive control groups
- appropriate to control for:
–> test-retest effect (improved performance with familiarity - better in test 2) - not appropriate to control for:
–> other factors that affected the period in between test and retest (e.g. motivation) because they don’t have the in between period
–> placebo effect as no training is done so the believed benefits of training aren’t present
evaluate the use of active control groups
- appropriate to control for:
–>other factors that affected the period in between test and retest (e.g. motivation)
–> placebo effect
Klingberg et al (2002) - seminal trainign study
- can intensive working memory training help children with attention deficits such as in ADHD?
- computerised training program with a variety of working memory tasks
- tested improvements relative to an active control group in the trained and in untrained tasks
- did training and transfer tasks
what was the design of Klingberg et al (2002)?
- pre test
- experimental group did training 5x a day (high dose)
- active control group did training 1x a day (low dose)
–> trained for 5 weeks - post-tests measured the change in the training and transfer tasks
results of Klingberg et al (2002)
- all groups got better at training and transfer tasks
- high dose see greater improvement in training scores than low dose
- high dose also see greater improvement in transfer task compared to low dose
evaluate Klingberg et al (2002)
- first evidence for training and transfer effects, but very small group sizes (n = 7)
Klingberg et al (2005) - seminal training studies 2
- multicentre, randomised controlled trial (N = 53)
- pre test
- 5 weeks training
–> adaptive training (experimental group)
–> non-adaptive training (control group) - post test
–> measure training and transfer performance - then a follow up after 3 months
–> change in training and transfer measured again
adaptive and non-adaptive training in Klingberg et al (2005)
- adaptive training = change in difficulty
–> the difficulty increases as you get better - non-adaptive training = same difficulty level
–> stay at the lowest level of difficulty
results of Klingberg et al (2005)
- training tasks:
–> larger benefits in adaptive relative to non-adaptive WM training group in the practiced tasks - transfer tasks
–> larger benefits in adaptive relative to non-adaptive WM training group in unpracticed inhibition and reasoning tasks
evaluate Klingberg et al (2005)
- scores in the write up were corrected for differences in baseline score
- evidence for training and transfer effects of working memory training
- however, although corrected differences are significant, uncorrected group differences in change are only small
Jaeggi et al (2008) - seminal training studies 3
- pre test
- training
–> working memory training vs passive control (no intervention) - post-test
–> measure change in training and transfer task performance
methods in Jaeggi et al (2008)
- experimental group did Dual n-back training –> n back + auditory stimuli
- the transfer task was a reasoning task (Raven’s task)
results of Jaeggi et al (2008)
training group better at training and transfer tasks in post-test compared to passive control
Redick et al (2013)
- pre test
- then 10 sessions of working memory training vs active control (visual search task, something but not WM) vs passive control
- then did a mid-test
- then did another 10 sessions (same as before)
- then did a post-test
–> measure change in training and transfer task performance
results of Redick et al (2012)
- no significant near transfer effects
- no significant far transfer effects (spatial reasoning and verbal reasoning)
the hype of working memory training
- training studies published 2002-2015
- hype and inconsistencies led to highly active field of research
does working memory work?
- inconsistent evidence across a large number of studies
- how can these inconsistencies be explained?
reasons for inconsistencies (methodological issues)
- lack of active controls
–> placebo effects - single tasks used for measuring cognitive abilities
–> task-impurity problem - small sample sizes
–> low statistical power and imprecise measurement
reasons for inconsistencies (theoretical issues)
- many studies lack theoretical framework of training and transfer
- without theory explaining mechanisms of transfer (i.e. why we expect effects) we can’t predict when we should observe effects
multiple sources of variance framework (mechanisms of transfer)
- intervention specific factors
–> impacts training and transfer - individual differences
–> impacts training and transfer - training impacts transfer
- transfer effects our observed effects
two proposed mechanisms of transfer
- enhanced capacity
- enhanced efficiency
enhanced capacity
- training increases the number of information elements held in working memory (i.e. larger broad focus of attention)
- prediction:
–> training leads to BROAD transfer effects
enhanced efficiency
- training supports a more efficient use of the existing capacity through strategies or faster processing
- prediction:
–> training leads to SELECTIVE transfer effects
De Simoni & von Bastian (2018) - mechanisms of transfer study
- pre test
- training for 20 sessions
–> WM binding
vs
–> WM updating
vs
–> active control (visual search) - then a post-test
the training in De Simoni & Von Bastian (2018)
- N = 197 young adults
- randomly assigned
- double-blind
- 4 tasks per intervention
the pre-post change in De Simoni & Von Bastian (2018)
- 4 tasks per ability
- trained abilities
- near transfer
- far transfer
results/conclusions of De Simoni & Von Bastian (2018))
- large improvements in the trained tasks
- no evidence for near transfer
- no evidence for far transfer
- training improved neither WM capacity nor efficiency
- BUT:
–> might be different for other WM tasks or measures of specific types of efficiency
training progress
- large individual differences in training progress
- in a complex span task there is often increasingly large individual differences
who benefits the most from training? (3 hypotheses)
- magnification
–> people with higher ability gain more - compensation
–> people with lower ability gain more - no difference
Guye et al (2017) study
- how are initial training performance and slope in training progress related?
- younger adults showed magnification of initial task performance
- little effect in older adults
intervention specific factors
- do training and transfer effects depend on the type of training task?
- do training and transfer effects depend on the dose of the intervention?
Melby-Lervag et al (2016) - meta analysis
- does effectiveness depend on the type of training task?
- N-back vs Cogmed vs complex span task
- On average, Cogmed induces relatively larger verbal near transfer, but n-back yields relatively larger far transfer
Melby-Lervag et al (2016) - meta analysis (dose)
- Does effectiveness depend on training dose?
- small vs large
- training dose has little effect
–> the only significant difference occurs for far transfer but in the opposite direction
–> i.e. small dose does better than large dose - type of training and dose have very small effects
individual differences
Possible factors:
- age
- gender
- personality
- motivation
- beliefs
Guye et al (2017) individual difference study
- how are demographics, personality, motivation, and beliefs related to the slope in training progress?
- limited evidence for individual differences predicting slope in training progress
- however, results may differ for samples with successful training and transfer
Is working memory training effective?
- training produces large improvements in the trained tasks but rarely transfer
- transfer effects, if existing, are small and volatile
- we can rule out a range of potential moderators but we still don’t know why training “works” better in some studies than others
the take home message
- enhancing WM could improve a range of other, functionally overlapping abilities
- transfer may occur through enhancing capacity or efficiency
- seminal training studies reported far transfer, but these findings are difficult to replicate
- multiple sources of variance may contribute to these inconsistent results
- don’t take results by their face value – critically assess the methodological quality