Abstracts of Conference Presentations – Posters and Talks
December 14th, 2011 10:20am
Sanchez & Reber – SFN 2011
Explicit knowledge influences consolidation but not immediate performance in implicit skill learning
Sanchez, D.J., & Reber, P.J. (2011) Society for Neuroscience.
Perceptual-motor sequence learning has often been used as a task for dissociating the neural mechanisms and operating characteristics of the explicit and implicit memory systems. Although neuropsychological and behavioral evidence indicate separable memory systems in the brain, the interaction of knowledge representations across the systems is likely to be vital in everyday activities. For instance, motor skill acquisition typically relies on explicit, declarative knowledge of what to do, which precedes the development of the implicit, procedural knowledge necessary for improving performance. Using the Serial Interception Sequence Learning (SISL) task, the effect of explicit knowledge on skill learning was examined in order to identify how the interaction of knowledge representations may benefit (or inhibit) performance. The SISL task utilizes perceptually-guided responding to intercept moving cues, and mimics real world skill expertise in requiring accurate timing and order between motor responses. A repeating sequence of cues can be covertly embedded in the task, which is then learned implicitly by participants. Across two experiments, adding explicit pre-instruction about the 12-item sequence prior to training produced no benefit in acquisition or performance in this task, even when explicit knowledge was exceptionally robust. In a second set of experiments examining skill learning consolidation, participants trained on two sequences (SeqA and SeqB) consecutively on one day and 48 hours later received training on a third sequence (SeqC), followed by a test of all three sequences. Retroactive interference between the first two trained sequences (from SeqB to SeqA) was affected by whether participants had explicit knowledge of the initial sequence (SeqA). Participants with relatively higher concomitant explicit knowledge of SeqA exhibited better retention at test for all three sequences than those with lower explicit knowledge (measured by sequence recognition). This relationship between recognition and performance was not found for either SeqB or SeqC. Curiously, while the ability to recognize this particular sequence predicted higher levels of sequence-specific performance improvements, it did not predict higher levels of corresponding explicit knowledge for the other sequences. Although explicit sequence knowledge did not directly translate to a benefit in initial acquisition or performance, a positive effect of explicit knowledge on motor skill consolidation may be related to the ability of the medial temporal lobe memory system in sorting and storing information representations without catastrophic interference.
Posted by Danny
November 7th, 2011 4:21pm
Sanchez, Yarnik, & Reber – MPA, 2012
Title: Coordinated action and timing responses separated across hands are integrated in sequence learning.
Area: Cognitive Neuroscience of Learning and Memory.
Problem or Major Purpose: Skill learning relies on a flexible explicit set of actions to perform which provides scaffolding for the relatively inflexible implicit representation supporting performance improvements through practice. A key question regarding implicit knowledge is to what extent the timing and order of sequential movements is specific and inflexible to what was practiced. Sanchez, Gobel, & Reber (2010) previously used the Serial Interception Sequence Learning (SISL) task to demonstrate implicit learning in healthy patients with little trace of associated explicit knowledge. In the SISL task, participants’ attempt to make a precisely-timed motor response to cues scrolling down a monitor toward one of four target zones. The cues follow a covertly-embedded repeating sequence of cue order and inter-cue timing. Other work examining the integration of sequential response order and timing with the SISL task has shown that these two sources of information are integrated during learning (Gobel, Sanchez, & Reber, 2011). This produces a surprisingly inflexible knowledge representation which resists transfer to very similar motor sequences.
Procedure: To test the hypothesis that sequence inflexibility arose from the need to combine order and timing information into a single keypress response, SISL learning was examined with a guitar-shaped manipulandum that separated action selection and response timing across hands and required a bimanually-coordinated response on each trial. Twenty-eight Northwestern University undergraduates (17 F, Mean Age = 21.3 years) participated for course credit. Participants completed 2880 trials of training on the SISL task, followed by a test where the order of cue responses and inter-cue timing were separately manipulated from the trained sequence in order to assess transfer to sequences with novel timing or novel order.
Results: Participants exhibited sequence-specific performance improvements for only the trained sequence and performance was equivalent to an unpracticed sequence if either timing or order was disrupted. Separate examination of each hand individually also failed to show any evidence of partial transfer from the trained sequence.
Conclusions and Implications: When response timing and order are both necessary for coordinated sequence performance, they become integrated in the motor plan that is necessary for expression even when expressed largely through different hands. These results have broader implications to educational training whereby rote practice of cognitive or motor skills may result in a hyper-specific, inflexible knowledge representation.
Mini-Abstract: Skill learning was examined with a guitar-shaped manipulandum that separated action selection and response timing across hands and required a bimanually-coordinated response on each trial. Participants exhibited sequence-specific performance improvements for only the trained sequence and performance was equivalent to an unpracticed sequence if either timing or order was disrupted.
Posted by Danny
November 2nd, 2011 2:18pm
Cognitive Neuroscience Society, 2012
Working memory training gains and transfer to other cognitive functions
Gigler, K.L. & Reber, P.J.
Recent research demonstrating improvements in working memory (WM) capacity has challenged the idea that WM capacity is an immutable cognitive trait. Indeed, relatively modest training protocols have been shown to lead to significant improvement. Because WM is a core cognitive process, increasing capacity has the potential to enhance performance on a wide range of cognitive functions. A critical question is the degree to which gains exhibited on the WM training task transfer to other cognitive processes. To test for transfer, the CogState cognitive assessment battery was completed by participants both before and after 10 hours of WM training with a novel training protocol. The CogState assessment battery includes a collection of tests that measure long-term memory function, executive function, attention and processing speed. During training, participants completed 2000 training trials of a visuospatial working memory task. Each trial consists of two phases: the presentation phase, during which participants see a sequence of moving visual cues and must hold that sequence in WM, and the response phase, during which participants attempt to replicate the sequence. The training is adaptive, adjusting the length of presented sequences based on performance in order to keep training near each individual’s WM span. Participants showed reliable improvement in WM span on both the trained task and a separate, non-trained assessment of visuospatial WM. Significant improvements were also observed on CogState measures of non-verbal long-term memory, attention, and processing speed, indicating that WM training can produce considerable gains in cognitive functioning beyond merely domain-specific WM improvement.
Posted by Kati
November 2nd, 2011 2:17pm
Entertainment Software and Cognitive Neurotherapeutics Society, 2011
Sequence-specific and non-specific gains in working memory following cognitive training
Gigler, K.L. & Reber, P.J.
Working memory (WM) refers to the ability to hold a limited amount of information in mind for a short period of time and is a core cognitive component important for many higher-level cognitive functions, including problem solving and language comprehension. An increasing volume of research indicates that individual WM capacity can be enhanced through training, potentially improving cognitive performance in a variety of domains; however, a major challenge to realizing the value of this approach lies in the tendency of WM gains to be domain-specific, limited to only trained material. The current research utilized a novel visuo-spatial WM training task based on a game-like sequence learning task. It is comprised of two phases wherein a sequence of moving visual cues is first observed and then replicated following a 2-second delay, during which the sequence must be held in WM. Training was adaptive in that the length of the sequences increased as participants improved, increasing demands on WM and maintaining a challenging and engaging level of difficulty. Participants completed 450 trials of training over 2 hour-long sessions across 2 days, with a repeating sequence of spatial locations covertly embedded in 20% of trials. Increased WM capacity was found after training for both repeating and novel sequences, although observed gains were larger for the repeating sequence. The sequence-specific improvements reflect the potential for hyper-specific gains in WM capacity following training, analogous to domain-specific improvements, while the task-general gains indicate the potential for expanding general WM function through cognitive training using this task.
Posted by Kati
November 2nd, 2011 2:16pm
Society for Neuroscience, 2011
Training on a game-like working memory task can improve visuo-spatial working memory capacity
Gigler, K.L. & Reber, P.J.
The question of transfer has emerged in studies of cognitive training that have found improvements in the trained cognitive processes, but inconsistent transfer of these improvements to other cognitive functions. Similar findings exist in the working memory (WM) literature; while domain-specific increases in WM capacity, or span, have been observed, such increases do not generalize to other domains. Because WM is known to be associated with individual differences in performance on tasks from problem solving to language comprehension, it is possible that succesfully training domain-general working memory could transfer to many other cognitive processes as well. Using a novel visuo-spatial WM training task, the current research demonstrates that working memory training can produce both general and domain-specific improvements following two hours of practice. The SISL-WM task is based on a game-like sequence learning task used to study skill learning. The task is made up of two phases, the first of which consists of the participant observing a sequence of moving visual cues across a computer screen that indicate a sequence of motor responses. After a 2-second delay interval, during which time the sequence must be held in working memory, the participant attempts to correctly replicate the cued motor response sequence. The task is adaptive in that the presented sequences increase in length as the participant improves with training and decrease in length if performance is poor, maintaining an acceptably challenging level of task difficulty. The number of cues in a given sequence is considered the participant’s current working memory span for the task. Sequences consist of either randomly ordered cues (80% of trials) or of fragments drawn from a covertly repeating 12-cue sequence (20% of trials). Participants completed 2 separate, hour-long sessions of adaptive training on the SISL-WM task. Working memory span on the task reliably increased from the beginning to end of training, improving for both random and repeated sequences. Furthermore, these individuals demonstrated significant improvement in working memory span on a different, untrained visuospatial WM task, showing some generalization of training gains. This demonstrates that the improvement in working memory span seen in training was not task-specific and benefitted viuospatial working memory more generally. These results indicate the viability of this visuospatial working memory task as a training task, and further suggest that training of working memory can indeed lead to generalizable cognitive improvement.
Posted by Kati
November 2nd, 2011 1:34pm
Sanchez, Yarnik, & Reber – CNS, 2012
Coordinated action selection and timing responses separated across hands are integrated in sequence learning
Daniel J. Sanchez, Eric N. Yarnik, Paul J. Reber
Previous work examining the integration of sequential response order and timing with the Serial Interception Sequence Learning (SISL) task has shown that these two sources of information are integrated during learning (Gobel, Sanchez, & Reber, 2011). This produces a surprisingly inflexible knowledge representation which resists transfer to very similar motor sequences. To test the hypothesis that this inflexibility arose from the need to combine order and timing information into a single keypress response, SISL learning was examined with a manipulandum (simulated guitar) that separated action selection and response timing across hands and required a bimanually coordinated response on each trial. Participants completed 2880 trials of training on the SISL task in which precisely-timed motor responses were made to cues moving along one of four columns that followed a covertly embedded repeating sequence of cue order and inter-cue timing. At test, the order of cue responses and inter-cue timing were separately manipulated from the trained sequence in order to assess transfer to sequences with novel timing or novel order. Participants exhibited sequence-specific performance improvements for only the trained sequence and performance was equivalent to an unpracticed sequence if either timing or order was disrupted. Separate examination of each hand individually also failed to show any evidence of partial transfer from the trained sequence. When response timing and order are both necessary for accurate coordinated sequence performance, they become integrated in the motor plan that is necessary for expression even when expressed largely through different hands.
Posted by Danny
May 11th, 2011 5:59pm
CNADC Alzheimer’s Disease Day, 2011
A comparison of implicit perceptual-motor skill learning in individuals with mild cognitive impairment and Parkinson’s disease
Gobel, E. W., Blomeke, K. M., Weintraub, S., & Reber, P. J.
Skilled performance of complex motor skills requires learning a specific order of movements with precise timing. The Serial Interception Sequence Learning (SISL) task has been used to study the neural basis of this type of perceptual-motor learning. During the SISL task, participants make computer keypress responses that coincide with the timed passage of spatial cues that move through specified target regions on the computer screen. Participants are not told that the sequence of cues repeats itself, but implicit learning of the sequence is reflected by improvement in performance of the practiced sequence with repetition. Learning the sequence without awareness suggests that this type of memory does not depend on the medial temporal lobe memory system affected in Mild Cognitive Impairment (MCI) and Alzheimer’s disease (AD). Instead, this type of learning may depend on the basal ganglia and corticostriatal circuits. These subcortical systems, rather than medial temporal regions, are implicated in Parkinson’s disease (PD). To assess the importance of these different memory systems for learning in the SISL task, cognitively healthy older participants (N = 15, mean age 70.6 years), individuals with a clinical diagnosis of MCI (N = 10, mean age 77.8), and those with a diagnosis of PD (N = 15, mean age 63.7 years) performed a 3-button unimanual version of the SISL task, with the initial speed of the moving cues set to an appropriate level of difficulty for each participant. During training, cues generally followed a 12-item repeating sequence over 1,440 training trials (11-39 min depending on individual speed). On a subsequent test phase, the cognitively healthy and MCI participant groups both exhibited reliable implicit sequence knowledge. The PD patient group, while not showing a task performance deficit, failed to show reliable sequence learning. However, the PD group was heterogenous: 2 exhibited strong sequence learning, 3 showed moderate (but reliable) learning, and 10 did not appear to learn. None of the groups could reliably identify the trained sequence, consistent with the unavailability of this form of learning to conscious recollection. These results are consistent with our hypothesis that serial interception sequence learning is not dependent on the declarative memory system impaired in MCI, but likely depends on the basal ganglia.
Posted by Kati
May 11th, 2011 5:46pm
CNADC Alzheimer’s Disease Day, 2011
Training working memory using a novel visuospatial task
Gigler, K. L. & Reber, P. J.
Though cognitive psychologists have long thought working memory span immutable, compelling recent evidence suggests that it is possible to improve other memory systems through various cognitive training programs. Furthermore, work done with older adult populations indicates that these individuals benefit from such memory training as much, if not more so, than younger adults. Because working memory is innately tied to executive function and other higher order cognitive processes which decline sharply in older adults, the training and improvement of this system could lead to transfer to various important cognitive processes in this population. Though truly successful working memory training has not yet been described, several laboratories have identified important and trainable aspects of working memory. The current research utilizes a novel visuospatial working memory task created with such previous research in mind. The task is designed in the style of a “replicate” task, with a first phase in which participants learn a sequence of items to be held in working memory, and a second phase in which participants attempt to replicate this learned task. A pilot study was conducted with an undergraduate population in which 21 participants completed 2 sessions of training on this task. A comparison of working memory span as measured through task performance found a significant increase in span across training, with the average span of individuals increasing from an initial span of 6.34 (SE = .23) to a span of 7.03 (SE = .37), p < .004. Furthermore, these individuals demonstrated significant improvement in working span on a visuospatial task used to test transfer of training gains, from an average pre-training span of 5.86 (SE = .51) to an average post-training span of 6.86 (SE = .46), p < .018. These results suggest that the novel task is a strong candidate for use in an older adult population, and future research in the laboratory will test the efficacy of the task in a longer-term training study with older adults. The incorporation of further measures of transfer into pre- and post-training assessment will aid in determining the extent of transfer of training gains to more general cognitive function.
Posted by Kati
February 28th, 2011 6:23pm
Cognitive Neuroscience Society, 2011
Cognitive depletion has a negative impact on the rate of implicit perceptual-motor sequence learning
Abigail H. Wesley, Daniel J. Sanchez, Paul J. Reber
Ego-depletion theory states that humans possess a limited store of cognitive resources that, when depleted, produce deficits in self-regulation or cognitive control. Depletion effects on implicit learning, which is not thought to require cognitive control, have not previously been reported. However, if depletion reflects transiently lower levels of dopamine, ego-depletion might be associated with slower learning for tasks dependent on dopamine-gated plasticity in cortico-striatal circuits. The relationship between ego-depletion and implicit learning was examined by comparing participants’ levels of cognitive depletion with sequence learning performance. Participants first completed the Stroop Task to assess depletion, measured as the reaction time difference between control and incongruent trials. Participants then performed the Serial Interception Sequence Learning (SISL) task. The SISL task is a perceptual-motor sequence learning task whereby circular cues scroll across a computer screen toward targets, and participants attempt to press the correct key when a cue fits within the target zone. Participants received 2880 trials of training on a covertly embedded 12-item second-order conditional sequence, followed by tests of both implicit and explicit sequence knowledge. Implicit sequence knowledge was assessed as the percent correct difference between performance on the trained sequence and novel sequences. A negative correlation was found between the interference effect and the amount of implicit learning exhibited, with a slightly stronger relationship observed for participants who did not demonstrate explicit knowledge of the sequence. These results show that ego depletion may lead to slower implicit learning, implying this process is not as automatic as previously hypothesized.
Posted by Abbie
November 30th, 2010 10:56am
Psychonomic Society, 2010
Combining Physical Exercise and Repetition-Lag Training to Improve Everyday Memory Function in Older Adults
Gigler, K. L., Jennings, J. J., Dagenbach, D., Katula, J. A., Dove, R. W., & Stark, S.
Cognitive and physical activity interventions have been shown to improve older adults’ performance on lab-based measures of memory and executive function. However, less work has examined the real-world benefits of these two types of interventions, particularly when administered in conjunction with one another. The present study, which was part of the Seniors Health and Activity Research Program pilot trial, explored the independent and combined effects of repetition-lag memory training and aerobic exer- cise training on the frequency of self-reported memory errors in older adults. Following 4 months of training, a significant decrease in errors was observed for both the repetition-lag-only group and the combined exercise and repetition-lag group, with no benefit for the exercise-only participants. These results suggest that repetition-lag training may be more efficacious than physical exercise for reducing everyday memory errors and that cognitive and physical activity training may not produce
additive effects when administered together.
Posted by Kati