July 15, 2008
[ 
, Artificial Intelligence, Cognitive Neuroscience, Developmental Psychology ]
To enhance any system, one first needs to identify its capacity-limiting factor(s). Human cognition is a highly complex and multiply constrained system, consisting of both independent and interdependent capacity-limitations. These "bottlenecks" in cognition are reviewed below as a coherent framework for understanding the plethora of cognitive training paradigms which are currently associated with enhancements of working memory, executive function and fluid intelligence (1,2, 3, 4, 5, 6, 7, 8, 9,
10, c.f. 11, 12, 13).
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Posted by Chris Chatham at 9:23 AM • 3 Comments
July 14, 2008
[ , Cognitive Neuroscience ]
Most readers of this blog are probably familiar with "unilateral neglect," one of several behavioral manifestations of brain damage to the parietal lobe. Perhaps fewer readers are aware of other findings from unilateral neglect patients which are often omitted from classic descriptions of this syndrome.
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Posted by Chris Chatham at 11:52 AM • 1 Comments
July 9, 2008
[ , Cognitive Neuroscience, Developmental Psychology ]
How would an ideal behavioral method for cognitive enhancement actually affect the brain? Perhaps cognitive enhancement would be accompanied by more activity in the prefrontal cortex, indicating more successful engagement of control - or perhaps by less, indicating more efficient processing? Perhaps it would be accompanied by a transition from prefrontal activation to parietal activation, suggesting more automatic processing of task information. Perhaps it would make representations in prefrontal cortex more abstract and generalizable, or perhaps it would cause representations there to become more specific and tuned to the particular demands of difficult tasks. These are just a few of many possibilities, and they may all be correct depending on what kinds of training we're talking about.
For example, tactile discrimination training yields large-scale cortical reorganization only for those areas of skin that have been trained (demonstrating highly specific training effects). However, the corresponding receptive fields for those areas of skin enlarge in sensory cortex, and neural recordings show earlier, higher amplitude, more rapidly oscillating, and more temporally focused activation in response to tactile stimulation. Similar effects were also observed in an auditory discrimination paradigm.
Of course, cortical representations are only one part of the network that is involved in such sensory training. Although subcortical reorganization has been observed after practice, it appears to occur only when cortical reorganization has also occurred. On the other hand, cortical reorganization can occur in the absence of subcortical reorganization.
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Posted by Chris Chatham at 3:56 AM • 0 Comments
July 7, 2008
[ , Cognitive Neuroscience ]
Training high-level cognition or "executive function" is not always successful. Interestingly, some of the least robust training effects come from one of psychology's most robust paradigms - the Stroop task.
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Posted by Chris Chatham at 2:40 PM • 2 Comments
July 3, 2008
[ , Cognitive Neuroscience ]
Klaus Oberauer has a fascinating paper from 2006 which seems to have been ignored by the cognitive training community. Oberaurer demonstrates how improper counterbalancing, ignorance of the power-law of practice, and confounds in the design of memory load tasks can substantially misconstrue the real effects of training on performance. This work has implications for the interpretation of improvements in n-back performance as a function of training, which has become a feature of several new websites in the wake of a study showing fluid intelligence is enhanced after n-back training.
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Posted by Chris Chatham at 5:16 AM • 0 Comments
July 2, 2008
[ , Cognitive Neuroscience ]
Self-selection refers to the fact that certain kinds of people may be drawn to certain kinds of lifestyles or practices (including participation in human research). When the effects of those lifestyles/practices are observed scientifically, they are confounded with myriad other factors which also characterize that group. For example, in the context of meditation studies, it is possible that meditation in the realm of 10-50,000 hours has beneficial effects, but is also difficult to prove the important factor is not all other characteristics of such avid meditators (for example, their tendency to sleep soundly or to drink green tea, etc).
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Posted by Chris Chatham at 12:13 PM • 5 Comments
July 1, 2008
[ , Cognitive Neuroscience ]
How does meditation experience functionally change the brain, and what effects does this have on distractibility? These are the questions addressed in a 2006 PNAS article from Brefczynski-Lewis et al, who compare expert meditators (between 10,000 and 54,000 hours of meditation experience) with two age-matched novice groups, one paid to help control for any motivation-related differences between groups.
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Posted by Chris Chatham at 11:04 AM • 2 Comments
June 30, 2008
[ , Cognitive Neuroscience ]
Attention training through meditation can reduce the duration of the "attentional blink" - in which detection of a first rare target causes people to be unaware of a second target presented soon after the first - according to research by Slagter et al from PLoSBiology.
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Posted by Chris Chatham at 10:20 AM • 7 Comments
June 27, 2008
[ , Cognitive Neuroscience ]
As discussed earlier this week, meditation may be an alternative form of brain training - or "brain untraining" - that shows transfer to tasks requiring cognitive control. There have been a few updates to this fascinating line of research, not least of which is a fascinating paper by Amishi Jha and colleagues from the University of Pennsylvania. They showed that relative to a control group, meditation influences particular components of attention in ways that are compatible with beliefs long held in the meditation community.
In particular, Jha et al focus on mindfulness meditation, which is defined as continuous and "non-judgemental" attention to the unfolding present, and has shown a variety of beneficial health effects (as described in a previous post). The meditation literature suggests there are two forms of mindfulness meditation: a "concentrative" form which involves continuous allocation of attention (e.g., towards breathing) and a "receptive" form which involves keeping attention in a state of readiness of preparedness. Interestingly, many meditation protocols suggest that the concentrative form must be developed first, due to the benefits it provides in limiting "mind wandering" during receptive meditation.
Jha et al connect these rather opaque terms to cognitive neuroscience with recourse to the Corbetta & Shulman model of attention. Jha et al suggest that "Receptive meditation" might involve the ventral attentional network (involved in monitoring the environment) whereas the "concentrative meditation" might involve the dorsal attentional network (involved in directing attention to particular stimuli or responses).
To test this idea, Jha et al recruited three groups of subjects: a control group of nursing students from UPenn, a "training" group of meditation-naive subjects who would undergo 8 weekly 3-hour sessions of meditation training, and a "retreat" group of experienced meditators who would go on a month-long mindfulness meditation retreat.
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Posted by Chris Chatham at 12:44 PM • 2 Comments
June 25, 2008
[ , Cognitive Neuroscience ]
In a fascinating review of the cognitive neuroscience of attention, authors Raz and Buhle note that most research on attention focuses on defining situations in which it is no longer required to perform a task - in other words, the automatization of thought and behavior. Yet relatively few studies focus on whether thought and behavior can be de-automatized - or, as I might call it if I were asking for trouble, deprogrammed.
What would count as deprogramming? For example, consider the Stroop task, where subjects must name the ink color of each word in a list of color words (e.g., "red" might be written in blue ink, and the task is to say "blue" while suppressing the urge to automatically read the word "red"). Reaction time is reliably increased when subjects name the ink color of incongruent words ("red" written in blue ink) relative to congruent words ("red" written in red ink), presumably because the subjects need to inhibit their prepotent tendency to read the words. But is it possible to regain control over our automatized processes - in this case, reading - and hence name the ink color of incongruent words as quickly as we would name the ink color of congruent or even non-words?
The Role of Meditation in "Deprogramming"
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Posted by Chris Chatham at 4:05 PM • 6 Comments
