What if training ourselves on one task yielded improvements in all other tasks we perform? This is the promise of the cognitive training movement, which is increasingly showing that such "far transfer" of training is indeed possible, while short of being "universal transfer." Interestingly, this phenomenon might be most likely to occur for some of the most abstract and challenging cognitive functions.
New evidence for this claim comes from an in-press article at Psychological Science, by Persson & Reuter-Lorenz. The authors used several tasks which have been shown to engage the left inferior frontal gyrus (lIFG) of the prefrontal cortex. The best theoretical interpretation of this activity is that the lIFG is "biasing" the activity of particular representations in posterior cortex. For example, you may need more of such "biasing" when trying to come up with a verb that's related to "giraffe" than one that's related to "lion" (lion has some obvious associates [roar! eat! hunt!] and is therefore less likely to require any help from lIFG). This is an example of a verb generation task; like many other similar tasks, it engages the left IFG.
Persson & Reuter-Lorenz used verb generation as a test for transfer - that is, subjects were never trained on this task, or the others used to assess transfer (which included tests of recognition and recall for items where lIFG is engaged). Instead, subjects were trained for 8 hours each on one of three versions of other tasks: all of the trained tasks required that subjects remember the groupings of recent stimuli (whether letters, words, or faces) but for some subjects these groupings were easily confusable (known as a "recent probes" version). It is those versions of the tests which are thought to involve lIFG, and on which training was predicted to have the largest effects.
Consistent with this prediction, only the group trained on the easily-confusable memory tasks improved on the untrained tasks. In addition, the observed improvement was roughly equal on all three of the untrained tasks, indicating impressive generalization of the trained ability. A critical additional analysis showed that the improvement showed by each individual on the trained tasks predicted each individual's benefits on the untrained tasks. This analysis is an important compliment to the group level analyses which are more typically done in experimental psychology, because it shows a one-to-one correspondence between training and transfer of that training.
A similar effect has been observed for training of a different brain region - the striatum - which is thought to be involved in "updating" the representations in prefrontal regions (like lIFG). Thus it appears that at least two critical components of this executive control system (active maintenance/biasing and updating) can be affected by training.
An interesting message from the Persson & Reuter-Lorenz work is that transfer of training may occur only when the same brain regions are activated across the training & transfer tasks. This was not observed in the wider fronto-parietal network in a study training the capacity for "cognitive updating," but they also did not perform the critical analyses at the individual level - so it's a little bit difficult to know what to make of that work, as discussed previously.
Another component of the executive control system is "switching" - as when we must rapidly change from performing one task to performing another. New work from Minear & Shah seems to show that some aspects of this capacity can be improved, but that paper is not yet available... I'll post an update when it is.
Thank you for the good information here. Your blog is really worth reading.
Whereas seeing far/ universal transfer is always welcome, I don't agree it is the only or main promise of cognitive training ("What if training ourselves on one task yielded improvements in all other tasks we perform? This is the promise of the cognitive training movement, which is increasingly showing that such "far transfer" of training is indeed possible, while short of being "universal transfer." )
There are a variety of objectives that may be accomplished (now or in the future) via cognitive training. One is indeed, following the title of your blog, "developing intelligence"/ enhancing overall cognition. But another set of objectives refer to better performance at specific tasks via training the specific & relevant cognitive functions: driving, flying a plane, trading, lowering attention-deficit-related symptoms...
Let me propose a physical fitness analogy. Some people may want to train their abdominal muscles to improve overall physical functional ability. Some to better compete in sports that place clear demands on abdominal muscles. Some to look better in a mirror.
The implication? we will need better and more widely available assessments to serve both as baseline and to direct people towards the cognitive training domains more relevant to their specific objectives. And more research on what type of intervention may help specific groups of people accomplish specific objectives (for example, comparing the relative & complementary benefits of physical and mental exercise).
I don't think he was suggesting that far transfer is or should be "the" primary goal of cognitive training, merely that it has had more of a "holy grail" mystique since it has been significantly less well established than 'short transfer.'
"The most abstract and challenging mental functions"...
I wonder what this means for games- traditional games, but more interestingly electronic puzzle games and other video games.
Any thoughts on how this might relate to the dual n back training task.
Thanks all for your comments, and I'm sorry that I've been delayed in responding. I've had my first paper under review (at various high profile journals - yippee!) and am now under a 2month deadline to address some serious concerns... so that has sapped much of my writing inspiration.
Gary - lIFG is a big player in n-back tasks (IIRC), although the function putatively trained in this work is maintenance, and not updating. In fact, the n-back training work could be interpreted to suggest that this form of training should NOT WORK (look at their control groups). In any case, I would think that this and n-back training would at least be partially targeting different functions, and therefore could be synergistic in a "training battery" (but of course that's speculation). It would be interesting to try to combine them, for example by using a recent-probes version of the n-back with distractors, or something.
Kyle, I actually do think that far transfer is a kind of holy grail, and should be a focus of much training work, since it offers the opportunity both to understand the structure of the integrated cognitive system in healthy adults, as well as a more time-efficient route to mental enhancement (relative to just training individual skills).
Nonetheless, I also agree with Alvaro that very targeted training may be useful in very specific situations.
Minear & Shah's paper is available. Will you be posting a write-up of their results?
Thanks Patent Guy for the notice! Yes indeed I'll look at it today and try to write something (probably won't post until next week). Thx again.
Many thanks for responding to my query about Minear and Shah as well as your great writeup of their findings.
I'm not a neuroscientist, unfortunately, having "discovered" a fascination with brain science long after the time when I made my career choice (I practice IP law for a living). Like many who read this blog, I have a particular interested in research on cognitive training, which is why I was interest in Minear and Shah's work.
Although I enjoy practicing patent law, my hope is one day to start a second career in venture capital and work with various types of startups, including those offering products related to cognitive training (e.g., Cogmed). In the meanwhile, I'd like to educate myself about the science underlying this "area" of research. If you have the time, would it be possible for you to provide a reading list, however short, of books and article that would be appropriate to my interests? I'm aware of your reading list on amazon.com, but feel free call out any book from that list. As far as my scientific proficiency goes, please presume a layperson with an armchair background in neuroscience, that is, someone who has read a fair share of the books intended for a general audience and is capable of getting the gist of a neuroscience article without an ability to grasp its nuances.
Thanks for your time and consideration!