Free How We Learn by Benedict Carey Page A

extraordinary condition, and learning scientists could hardly rely on it to measure the effects of emotion on the rest of us. For most people, moods come and go, coloring our experience rather than defining it. Their impact on memory, if significant at all, would be far weaker than for those with bipolar. And to measure this impact in a rigorous way would mean inducing the same mood in groups of people, reliably and continuously. That’s a tall order, so learning scientists began to focus not on moods per se but on the influence of differing “internal mental states.” Altered states.
    This was the 1970s, after all, when hundreds of thousands ofyoung people were experimenting with consciousness-altering drugs, primarily LSD and marijuana. These recreational users, many of them college students, weren’t interested in the effect of the drugs on their grades—they were enjoying themselves. Yet there were all sorts of rumors about the possible benefits of such substances on learning. Hallucinogens were said to be “mind-expanding,” capable of opening up new ways of thinking about the world. Pot allowed the brain to see connections it hadn’t before (often too many, resulting in late night sessions full of perfect nonsense). Clearly, altered states intensified experience; might they intensify memory?
    The rigorous research into our inner study environment would begin with drugs—the recreational kind. And its primary sponsor was the U.S. government, which, beginning in the early 1970s, funded a string of experiments that might be called the Studying Under the Influence series. By then, a scattering of research reports had already appeared, suggesting that some drugs, like barbiturates and alcohol, could produce so-called state-dependent learning in modest amounts—the “Study Aid” effect. The government-backed researchers wanted to clarify the picture.
    These experiments tended to follow a similar blueprint: Get people high and have them study something; then give them a test hours later—either after getting high again or after ingesting a placebo. We’ll take a close look at one of these studies, to show what serious scientists and serious stoners can do when they put their heads together. In 1975, a research team led by James Eric Eich of the National Institute of Mental Health set out to test the effect of pot on retention (word lists again), as well as learn something about how the drug alters what the brain doeswith newly studied information. The researchers recruited thirty college students and recent graduates, brought them into their lab, and gave each a joint. Half of the group got a real one and half got a “placebo marijuana cigarette,” which looked and smelled real but delivered no THC, the active drug. “The subjects took deep inhalations, maintained them for 15 seconds, andrepeated this process every 60 seconds,” the authors wrote. “The entire cigarette was smoked, with the aid of a holder, usually in about eight minutes.” These were not novices. On average, the participants smoked pot about five times a week. Within twenty minutes, those who smoked the full-strength joint were moderately high, based on their own ratings and physical measures, like pulse rate. Those who smoked the placebo did not show the same physiological changes.
    At this point, all thirty studied.
    They were handed sheets of paper and given a minute and a half to try to commit to memory forty-eight words. The words appeared grouped by category—for example, “A type of vehicle—streetcar, bus, helicopter, train,” or “A musical instrument—cello, organ, trumpet, banjo.” The categories were part of the experimental manipulation. We all look for patterns when trying to memorize a long list of items, bunching together those that look or sound the same, or are somehow related. The scientists wanted to see whether smoking pot influenced these “higher-order” cues we use to retrieve information later on, so they