[SOUND] So what is the role of control in language? Well, earlier we suggested that Piaget's theory of development, which proposed that the development of symbols was quite important, was already indicating how control, or the ability to imagine something that's not there, was present in the use of single words by children. Now they could say milk, and even though milk was not in the environment, mommy could, could then go, get milk, put it in a glass. This would suggest that controllabilities, indicated by brain signals, might help us understand which children are going to develop language more quickly. And, in fact, there has been work on that, looking at the nature of EEG coherence, right? The coherence of the electrical signals of neurons firing. And how that might predict when children will learn language. And, in fact, there has been, those measures have been gathered at different points in childhood and then looked at with regard to later development of language. In another study at UCLA conducted by Susan Bookheimer and her colleagues, they looked at children who were shown a string of letters and then asked whether one of the letters was present. String of letters was originally in upper case. The target letter, for which the child had to decide was that in the string or not, was in lower case. So, wasn''t the same form, but it had to be the same letter. And they had what they called a high load condition and a low load condition. In the high-load condition, what happened is they had many letters. In the low-load condition, they had fewer letters. And this allowed the researchers to look at the effects of load and also the effects of age. What they found was that, in general, children began to show smaller and smaller load effects as they got older. And these effects diminished considerably in adolescence, and then stayed small in adulthood. The difference between adolescence and adults was very small behaviorally. But when they looked at the brain activity, they noticed that there was considerable difference in the brain activity between adolescents and adults in this frontal parietal circuit. Again, the dorsolateral prefrontal cortex, the inferior parietal lobule, those areas showed much more activity in the adolescents than the adults even though the behavior was virtually identical and indistinguishable. This suggests that even though adolescents are performing like adults, their brains are having to work more than adult brains do. And perhaps, as many adults know, adolescents are not adults. And the idea that they can be adults younger and younger, again, like Nim Chimpsky, has a limitation, and that is the limitation of the development of the prefrontal cortex. And the fact that it is on a timeline and that that development can only be accelerated so much, and that there's a limitation, and there's a need for this development to occur in order to arrive at adult behavior with adult brain activity. Similar findings have also been observed by Amy Finn and Mark D'Esposito at University of California, Berkeley. They found that adolescents and adults show virtually identical behavior on a high load and low load task. But when the brain activity is observed, there is substantial differences between adolescents and adults, again suggesting that the brain activity shows a latent difference even though the behavior appears to show no difference. Another area that Finn and D'Esposito found was more active in young adolescents was the hippocampus. As you remember, we talked about the hippocampus earlier when we talked about HM and the fact that he lived in a world where he was constantly waking from a dream. He had no ability to form new long-term declarative memories. He could not talk about any person that he had met after his surgery because he could not form new long-term memories. This area was more active for young adolescents, suggesting that the young adolescents were not just doing the task, they were actually creating memories. And so, again, this suggests that there's some form of learning that's occurring in young adolescents. Even though the behavior is the same as a group of older adolescents, the truth is, the brain is actually forming memories in this case, and that suggests a difference in processing. So we've talked about control, and we've talked about development, and we've talked about it within language and outside of language. And I want to end with a quote that I think explains a lot about the nature of control. Every response which an individual makes is in a sense an act of adjustment. Every stimulus that comes to a responding organism is in a sense a test of the adaptability, the power of adjustment, possessed by that organism. The simple reaction time stimulus calls for a simple adjustment. The complex mental task calls for a more complex adjustment. Between the two there is a continuous gradation. When we pass from the isolated simple response to responses of a continuous serial character, we enter a field where the influence of a mental set begins to take form. The mental set is itself an adjustment. It is a response pattern of a given character, called into being by previous stimuli, deriving its strength from previous practice. It initiates preparatory reactions prejudicial to a given type of response. The efficiency of a mental set is expressed in part by the degree to which it wards off irrelevant reactions, in part by the facility with which it effects the adjustment required for each successive response. Just as a mental set is an adjustment in terms of higher units, so shift is an adjustment called into play by a superimposed mental set or by a forced change brought about by a change in stimuli. The two are inseparable. The uniformity of a mental set, or the high efficiency with which it may operate, does not bespeak the absence of shift. The necessity for shift continues to be operative in the form of constant readjustments even though these may be hidden by the influence of practice or other factors. The interesting thing about this quote is that it doesn't apply directly to all of the types of tasks that cognitive psychology uses on a daily basis. It could be applied to cooking, or driving, or any of the other things that we do every day. In fact, this shifting that's talked about in this quote could refer to development. Development is the act of going from one type of task to another type of task, of going from the simple to the complex. And this quote captures a lot, not just about the act of task switching, but perhaps about the act of development itself. Now the question is, whose quote is it? Well, this is Arthur Jersild from 1927. And even back then, he was anticipating the importance of this field without knowing it and giving us this very rich metaphor for thinking about development and our everyday lives.