The World of Caffeine (53 page)

In summary, the effects of caffeine as an athletic performance booster are still uncertain. It remains for future researchers to satisfactorily evaluate caffeine’s effect on an ordinary activity such as walking, by designing an experiment comparing the effect of a range of caffeine doses on well-hydrated, moderately trained subjects walking in controlled environments for an extended time. Such low-intensity exercise studies would help determine caffeine’s part in FFA mobilization.
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The saying goes, “You can’t be too rich or too thin,” to which perhaps could be added, “or too smart,” because, even if each man is correct about how bright he conceives himself to be, he would find it still better to be even a bit sharper. How far would you go to acquire, for example, a drug that would enable you to perform better on an IQ test, an SAT test, or a Bar examination? Or one that would help you to prepare your taxes or balance your checkbook more accurately, solve chess problems or crossword puzzles more readily, make better investments, or program a computer with more acuity, or even drive home more safely? Surprisingly, you might not have to go very far, because caffeine, in many ways, is a “smart pill” that can do just those things.

As demonstrated by scientific evidence and common experience, caffeine is a rare and wonderful substance that safely improves many mental functions, including alertness, memory, learning, and cognition. As early as 1933, one researcher analyzed the effects of caffeine on solving more than 250 chess problems, comparing performance of test subjects with and without caffeine. He observed a consistently remarkable improvement in performance with caffeine.
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Such improvements were reflected in a 1960s advertising campaign that dubbed coffee “The Think Drink.”

However, as to what the nature of this improvement may be or how great its extent, there is little agreement anywhere. Some people are convinced that they can’t think clearly or precisely without caffeine, while others say it makes them jittery and error prone. Naturally, behavioral scientists have been eager to discover the secret of caffeine’s ability to improve the brain’s information processing. Two complementary hypotheses explaining this remarkable power are supported by experimental data. The first hypothesis, sometimes called the “non-specific energetic” theory, attributes caffeine’s enhancement of mental functions to a generalized energizing effect. The second hypothesis, sometimes called the “specific cognitive” theory, attributes these enhancements to specific effects on brain or neural activity. Finally, a “cognitive-energetic” theory, combining the two, has also been formulated and may offer the most complete and best-integrated elucidation of the phenomena.

J.E.Barmack, in a paper published in the
Journal of Experimental Psychology
in 1940, was one of the first to advance the non-specific energetic theory. Barmack recognized the possibility that caffeine’s overall antihypnotic and antifatigue properties could be part of the story, but, observing that caffeine increased the rate at which people can add numbers, advanced the notion that caffeine acts non-specifically on “some central process or processes concerned with alertness” that “allay the development of a bored attitude to a task.”
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This idea is supported by many studies of continuous performance, over a period of a half-hour or more of what experimental psychologists call a “vigilance task,” one that requires prolonged attention and responsiveness but little physical activity. In real life, caffeine improves long-term performance on vigilance tasks such as solving arithmetic problems, driving a car, or flying an airplane. Its effects are most apparent when people have been working at their tasks for some time and are minimal when tasks are just begun. When people are allowed to take breaks to alleviate boredom and fatigue, no significant benefit from using caffeine is observed. These findings, based solely on studies of vigilance tasks, apparently confirm Barmack’s theory, that caffeine acts by “refreshing” a fatigued person, so that the enhancing effects of caffeine on long-term performance will obtain on any task that is performed repetitively, monotonously, and requires continuous attention.
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The specific cognitive theory, championed by H.Nash in his 1962 book
Alcohol and Caffeine,
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asserts that caffeine acts directly on “specific neural capacities” that are intrinsic to a given task and that it enhances performance on these tasks irrespective of whether a person is fatigued. This idea was suggested to Nash by his examination of performances of several different short-term tasks, some of which exhibited improvement after caffeine was ingested, while others remained unaffected. Nash argues that the benefits of caffeine on performance depend not on an improvement in general energy levels,
as Barmack had asserted, but instead on specific benefits related to the nature of the task at hand. Abandoning the metaphor of the organism as an energy system, Nash relied on another metaphor, one that became and remains the most generally accepted in cognitive psychology today: that of the human organism as an information-processing system. He observed improvement in the performance of a number of tasks, such as adding numbers, immediate recall, and word fluency. These benefits were realized even on brief tests administered when the subjects were rested and alert, and neither fatigued nor bored. In contrast, he found no improvement in tests of abstract reasoning, using language, deduction, estimating time intervals, or spotting arithmetic mistakes. The overall conclusion from such studies has been that caffeine “facilitates the speed, but not the memory, component of the task.”

If Barmack’s non-specific energizing theory is correct, we should expect caffeine to improve cognitive performance only when a person has become bored or tired. If Nash’s specific cognitive theory is correct, we should expect an improvement even when a person is rested and alert to start with, but this improvement would be observed only in some tasks and not others. However, because these theories are complementary rather than inconsistent, which is to say, they could both be true at the same time, we must also consider the syncretic hypothesis of A.F.Sanders, who argues that the improvements in mental capacity caused by caffeine are a function of
both
the energy level of the subject
and
the cognitive nature and demands of the task.
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Aiming to unite the energetic and cognitive models of human information processing, Sanders published his idea in 1983 that caffeine’s effect on performance is best understood as a function of both the energetic state of the person and the cognitive requirements of the task.

Unfortunately, even with the advancement of Sanders’ cognitive-energetic theory, the scientific community remains far from a complete and consistent explanation of caffeine’s sometimes apparently paradoxical effects on human performance. For example, an adverse effect has been observed on the attempt to repeat numbers backward, while a beneficial effect has been observed on the attempt to repeat them in their original order. In addition, caffeine impaired some factors of cognitive intelligence, while improving those related to speed. In other cases, caffeine had a deleterious effect on a given task until that task was practiced, whereupon the use of caffeine resulted in an improvement.
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Another troubling inconsistency is the low level of test-retest reliability. That is, the results of studies of caffeine’s effects, particularly on the performance of complex tasks, vary widely, forcing us to wonder which conclusions are the correct ones.
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Nevertheless, overall, scientific studies have confirmed some specific effects on cognition and learning: Caffeine improves the performance of simple, familiar, routine tasks, and it impairs or fails to affect the accomplishment of complex, novel, unpracticed tasks. Perhaps the reason for this difference is that, by conferring extra energy, caffeine causes a person to work more quickly but possibly less carefully.
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This explanation is in line with experiments that show that caffeine can stimulate fast and strong but incorrect reactions. For example, an experienced computer programmer may report that using caffeine makes well-practiced programming assignments easier to complete, while it appears to sometimes interfere with the successful solution of new and very difficult programming problems. Because real-life problems frequently present both sorts of challenges, and the nature and distribution of these challenges will vary as among different subjects performing the same tasks, caffeine should be expected to produce a complex array of sometimes contrary effects. In other words, although in some ways caffeine may give us a beneficial boost in our capacity to perform certain tasks, in others it may induce us to make precipitous, overeager choices, or to “jump the gun,” interfering with the circumspection necessary for accurate decisions. Perhaps a quick trigger finger is good for the artist’s hand, if the testimony of artists, musicians, and writers such as Balzac, Voltaire, Samuel Johnson, Beethoven, and Goethe about caffeine’s importance in their creative lives is to be accepted. However, psychology, which has yet to attain a coherent understanding of creativity, cannot shed much light on caffeine’s effects on the creative process.

In the laboratory it is easy to create experimental tasks, such as one requiring subjects to identify or remember numbers or colors flashing across a screen, in which few if any of the study’s participants will have been previously practiced. In life, however, most significant tasks are repeated and even systematically studied and practiced with the intent of improving performance. In addition, in many work situations, because people choose the jobs they pursue, they will often be performing those tasks for which they have the greatest innate abilities. For these reasons, it is essential, in predicting the effect caffeine will have on a person’s performance of a given task, to take into account not only the features of the task itself, but also to reckon with the competency of the person performing it.

Is programming a computer difficult or easy? Many people would find even basic programming tasks challenging, complex, novel, and creative. Experienced, well-practiced, and talented programmers might find many of these same programming tasks easy, simple, familiar, and routine. Caffeine might therefore affect performances on a simple programming test in opposite ways: The performance of the person who had little competency with programming, either because of lack of specific experience or specific ability, might well be impaired by caffeine. The performance of the person who was eminently competent in programming, either because of extensive experience or specific ability, might well be given a significant boost.

The effects of caffeine on task performance in real life are complicated still further by the fact that life’s tasks are compound in nature, and, even for the same person, certain elements of a task may be challenging and other elements easy, so that caffeine would exert a variable effect on different stages and parts of the task. We can reasonably speculate that, overall,
the more competent you are in performing a task, the more caffeine will help you do even better, while the less able you are in coping with a task, the more likely it is that caffeine will fail to affect or even impair your efforts. If this notion turns out to be true, the use of sufficiently large doses of caffeine, by tending to push lower scores lower and higher scores higher, should serve to flatten the bell curve of an IQ test into a sort of flying saucer.

A curious twist to this question is the possibility that caffeine may affect introverted people differently from the way it affects extroverted people. One study concluded that, when posed with challenging mental tasks, such as proofreading or solving mathematical problems, impulsive, extroverted people get a boost in performance from caffeine, while those who describe themselves as less impulsive and more introverted often suffer marked detriments after caffeine ingestion. Another study of caffeine’s differing effects on extroverts and introverts performing both simple and complex tasks came to similar conclusions. The routine or simple task was to pick out a letter each time it occurred on a page of type. The challenging or complex task was to answer word analogies and sentence completion questions from the Graduate Record Examination. This study seemed to confirm that everybody tends to do better the higher the dose, if the task is extremely simple. However, on the complex task, the extroverts’ performance improved in a dose-dependent correlation with caffeine, while the introverts’ performance worsened.

One additional possibility pertaining to competency comes to mind: If caffeine’s impairment of challenging tasks is a result of prompting us to “jump the gun,” perhaps a person can learn to compensate for this sort of overeager “coupling” even when riding high on caffeine, learning to pause in order to perform the necessary evaluation for a correct choice. If this can be done, then a savvy caffeine consumer might find that he can multiply the number of tasks in which caffeine is helpful and the degree to which it is helpful, and reduce the number and degree to which it causes impairment.

In recent years, in addition to continuing studies of caffeine’s effects on complex mental activities such as reasoning and learning, researchers have paid increasing attention to its effects on short-term memory. Overall, the results show that caffeine improves performance on tasks that require remembering small amounts of information and impairs or leaves unaffected performance on tasks requiring remembering a great deal. An example of a more demanding sort of memory task is a test in which subjects listen to or read long lists of words and are then asked to remember as many as possible. The experimenters note either no effect from caffeine or perhaps even a small impairment. Another way of conceptualizing these effects is provided by the Humphreys-Revelle
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model, according to which tasks that are primarily dependent on information processing, such as vigilance, simple arithmetic, or reaction time, are improved, because they make relatively small demands on short-term memory, while tasks with a high short-term memory component may be unaffected or adversely affected. Unfortunately, there is much ambiguity in the data that do exist about these effects. When weighing the conclusions of existing research, we would do well to remember a well-designed 1974 memory experiment by researcher V.E.Mitchell and his colleagues, the cautionary results of which were reminiscent of the title of Luigi Pirandello’s play
Right You Are, If You Think You Are,
because they seem to demonstrate that performance was improved by caffeine when and only when the participants were told that they had ingested the drug.
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