RJ: In shifting from task to task at that level, does it take a certain amount of time to really get into the task where you can pay full attention to it?

MP: Yes, and that time is definitely measurable by psychological experiment. On the other hand, it isn’t like twenty minutes or so. It’s in, probably, millisecond-to-second range to shift from one task to another. In terms of the overall day, or what people are trying to talk about in terms of being able to do more than one thing at a time, in the gross lay sense, it isn’t really severe punishment, but it does cost. And these costs can be measured.

RJ: Is there any indication that young people, for instance, who were brought up instant-messaging while watching TV, are able to do this better than adults? And that, kind of, some of the issues people are bringing up about information overload and that sort of thing actually has to do with the amount of training?

MP: Uh, the question about whether young people, being raised in a more Web culture, are better able to do this than their older contemporaries not raised in that culture… as far as I know, that question hasn’t really been definitively answered. My guess would be that they’ll have made certain adaptations, or developed certain skills. Anyway, in older age, we lose some of these abilities, probably due to changes in the nervous system that come with age, so although I can’t really say that the definitive experiments have been done, it seems quite likely that people raised with access to all the information that’s available on the Web with the click of a button are maybe better able to take advantage of it than people who are always having to write things down, go to the library sometime later and so on.

RJ: So if there’s a finite amount that we can pay attention to at a given time, is it possible to overload the brain circuitry over a larger period of time? Throughout our day, the more things we’re exposed to, the more stimulus, that the less our ability is to pay attention?

MP: The question of whether we can overload and get fatigue… again I might have a little difficulty in pointing to the best studies that deal with this, but it seems almost certain that we can get fatigued from high mental effort during the day. And that is like any other kind of fatigue; it requires a certain amount of restoration. There are psychological theories to this effect—that restoration is required after intense mental effort—and that seems likely to be the case. But, again, I’m not certain we have the definitive answer to this question.

RJ: Is that the sort of thing where, if you were exposed to lots of flashing advertisements and signs, thatpotentially those could be forces that wear us down?

MP: This is probably less likely. It probably depends on how much you process this information. So I think that the key probably arises from exercise of the attentional networks, not just from exposure to flashing lights and so on. Because we’re pretty good at being able to, you know, tune out some of this. But, again, I don’t know… obviously, the more effective the ads are in getting in and getting some processing, the more they will probably take your sources and lead to a certain amount of fatigue.

RJ: Going back to the three aspects of attention—alerting, reacting, and executive—do we have an idea why our brains are this way? The evolution process or that sort of thing?

MP: So the evolution of these brain networks… two of them are extremely old; one of them, certainly the alerting network, goes back to the animal kingdom, and it has to do, of course, with the way in which the animals adapt to awaking and sleep and Circadian rhythms, the rhythms of the day and so on—these are ancient networks. Different animals have of course adapted in somewhat different ways. Why we change in alertness over the day, why we have a diurnal cycle and so on, I’m not really able to say.

There are quite a number of theories on why this is so, but it certainly is ubiquitous in the animal kingdom. The orienting network has been studied in all the way down to rodents and so on, and although there are certainly lots of differences that occur between rodents and monkeys, and then some differences between monkeys and humans, these networks have been preserved pretty well in evolution, probably because they work effectively. The executive network seems to have a very big change between primates and humans. There are cells available in the anterior singular in humans—and to a lesser degree in some great apes—that aren’t available in even other monkeys (non great ape monkeys). These cells provide greatly increased connectivity between the executive network and other parts of the brain, and that, I believe, underlies the human skill at self-regulation—although obviously we’re not as skillful as many of us would like to be, but in comparison to cats or other primates, we’re highly skilled at being able to bring a coherent focus of attention over relatively long periods of time, and this seems to be a late evolutionary adaptation, and probably is one of the things that make us human.

RJ: So it seems that some of these systems are ancient; some are, at least in evolutionary terms, pretty new. Where does that leave us in the 20th and 21st century, in the information society?