How to Become Smarter (5 page)

There are a lot of books claiming that physical exercise and brain training (mental exercises) will improve brain function and make you smarter. These claims are based on statistical or correlational studies ([
957
,
958
] and Table 2 in [
959
]) and other circumstantial evidence, which cannot prove the point one way or the other. Direct experiments, on the other hand, show that physical exercise programs do not produce consistent benefits in academic performance and intelligence. Physical exercise programs have no effect on IQ scores of people suffering from mental retardation [
960
,
961
]. Numerous studies on healthy children and adults have yielded inconclusive results ([
962
-
964
] and Table 1 in [
959
]). If we are talking about becoming smarter, fluid intelligence is the most relevant mental ability. Exercise programs do not improve (academic) fluid intelligence or the improvement is tiny and statistically insignificant [
960
-
964
]. In the study by Mohamed Elsayed and colleagues [
963
] the total difference in fluid intelligence before and after an exercise program was not statistically significant (36 test subjects total) and the size of the improvement was miniscule. One component of fluid intelligence out of four remained unchanged, one decreased, and two increased slightly. In the study by A.K. Brown and colleagues [
962
] an exercise program, which included 82 test subjects, did not produce a statistically significant change in any components of fluid intelligence. According to Table 1 of the article [
962
], there was a slight increase in two components and a minor decrease in two other components of fluid intelligence in the exercise group. We can conclude from these studies that the cognitive benefits of physical exercise either do not exist or they are too small. Physical exercise will not make you smarter.

There may be some exceptions or qualifications to the above conclusion. Sometimes mental abilities are impaired as a result of a physical illness or a physical disability. In this case physical exercise may help to restore the cognitive abilities to some extent [
896
,
965
,
966
]. This may happen by means of the improvement of the general state of health (this is recovery from an impairment, not enhancement of the norm). Other studies show that physical exercise has transient effects on some mental abilities, such as information processing speed and attention control [
967
-
969
]. These effects disappear within one to two hours after a bout of exercise. A recent article shows that an exercise program can improve memory in healthy older people, but the size of the effect is small [
970
]. Still other studies have demonstrated that professional athletes perform certain tasks (related to their type of sports) more effectively than average people [
971
-
975
]. Yet the studies listed in this paragraph do not show that physical exercise will increase intelligence of a healthy person.

As for mental exercises or “brain training,” the conclusions are similar. Two large studies in adults have concluded that mental exercises do not improve general mental abilities such as fluid intelligence, short-term memory, attention control and so on [
917
,
918
]. The benefit is either miniscule or non-existent. Mental exercises do improve the skills related to the type of exercise that a person performs. In other words, with time and practice, people tend to learn how to perform various mental tasks better and more quickly. Nonetheless, there is no improvement in the general mental abilities and in the performance of mental tasks unrelated to the mental exercises.

There are some exceptions too, which, however, do not change the overall conclusion. One recent study has found that half of children may improve their short-term memory and fluid intelligence as a result of a special type of mental exercises [
976
]. This benefit was almost undetectable in the other 50% of children and the average improvement in fluid intelligence (all children combined) was small. That mental exercises can improve brain function in some children is an interesting and important finding. Nonetheless, to prove the validity of this finding, one or more independent groups of researchers have to confirm it. In academic science, when a group of researchers reports an exciting finding, other laboratories often show that the results are false. Similarly, Helga and Tony Noice published a research article showing that theater training can improve mental abilities in older adults living in retirement homes [
977
]. Only a single group of researchers has done this experiment so far, and the study deals with recovery from an impairment, not enhancement of the norm. Numerous other studies fail to show a significant benefit from mental exercises [
917
,
918
], and we can conclude that mental exercises do not enhance mental abilities in the majority of people.

An analogy with a desktop computer can illustrate this point. Mental exercises are similar to loading more software on the computer and making the computer work harder and longer. This approach cannot improve computer hardware: processor speed, memory, and the size of the hard drive—the characteristics that are “mental abilities” of the computer. Note that certain types of daily mental tasks do produce subtle changes in the brain structure of humans [
972
,
978
]. Yet these alterations are a “change” or “adaptation,” not an “upgrade,” because they do not improve brain function in general. (To continue the computer analogy, if you make the computer work harder, the fan cooling the processor and the indicator of hard drive activity will be constantly on. These changes do not mean that you have upgraded the computer by means of the excessive work load.)

My own experience with physical exercise and brain training leads me to the same negative conclusions. Whereas physical health benefits of physical exercise are indisputable, this approach is unlikely to have any significant effect on intelligence, in the vast majority of cases.

• Numerous studies show that physical exercise either does not improve intelligence or the benefits are too small.
  
• The same is true of mental exercises.
  
• Physical exercise has moderate effects (lasting one to two hours) on alertness, information processing speed, and attention control, but the improvement in fluid intelligence is negligible or undetectable.
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We reviewed some introductory information in the previous sections and now it’s time to introduce the first theory of several presented in this book. First, I would like to refresh your memory on the basics of the theory of evolution. This is necessary because the “natural nutrition theory of intelligence” is based on evolution. (Readers can skip the refresher by pressing the skip button or
this link
.)

Each form of life (a living organism) inherits traits (features) from its parents and this process involves genes. A mutation in a gene can cause an old trait to disappear or a new one to appear in the offspring. Evolution is the gradual change in living organisms over generations, a process mediated by genetic changes. Life forms of the same species often coexist as a group called a population, which occupies a certain geographic location or an ecological niche. Natural selection is a process of accumulation of those traits within a population that are useful for survival and reproduction of an organism. Natural selection also involves a process of gradual disappearance of the traits that impede successful reproduction and survival. Genetic changes (mutated genes) that provide an advantage to an organism become more widespread within the population because organisms carrying those mutations are more likely to survive and to procreate. The process of natural selection makes a population genetically adapted to its environment. Put another way, most of the individual plants or animals (or other life forms) within the population become well adapted to the environment that the population inhabits. Individuals become more adept at evading predators, at obtaining food, and at digesting the types of food that are present in a given environment. Separate populations of the same species of plants or animals can develop into new species if there is no genetic exchange (cross-breeding) between these populations, or if the genetic exchange is limited. For example, populations can become isolated geographically for an extended period of time that covers hundreds or thousands of generations. This change can form new species (a process called speciation). Charles Darwin was the founder of the evolutionary theory. His seminal work, “On the Origin of Species” (1859), laid the foundation of modern evolutionary biology and the related biological sciences. Later developments in genetics, archaeology, and other sciences led to the Modern Evolutionary Synthesis, which is the modern understanding of the process of evolution.

The rate of evolution (the speed of change) varies over time. The current mainstream view is that the rate of evolution is not constant. Evolutionary changes occur by leaps and bounds. Certain periods of time (tens of thousands of years) involve rapid changes, and then follow long periods when little or no change takes place (hundreds of thousands of years). Thus, short periods of rapid change alternate with longer periods of slow change. Nonetheless, evolutionary changes are gradual and take many generations (hundreds or more), even during periods of rapid change. Numerous studies have proven the evolutionary theory, and evolution by natural selection is an accepted fact among professional biologists [
38
].

Now we can get started on the natural intelligence theory (this is an abbreviation of the “natural nutrition theory of intelligence”). There are two notable differences between the diet of primates (and other animals) in the wild and a typical human diet. The first difference is that a typical human diet in industrialized countries is chockfull of various artificial ingredients that animals do not consume. These include food additives (salt, sugar, vinegar, nitrates, nitrites, monosodium glutamate, and others) and dietary supplements (artificial vitamins, minerals, and herbal extracts). The second difference is that animals living in the wild consume food that is raw (uncooked), whereas humans consume a predominantly cooked diet. In other words, modern primates [
39
-
41
] and evolutionary predecessors of humans consume(d) a 100% raw diet that is free of any artificial chemicals [
42
-
45
]. It seems logical to hypothesize that this sort of diet, or a similar diet, is more “natural” for the human brain than the typical modern diet. The food additives have been present in the human diet for less than several centuries [
43
], whereas the cooking of food has been with us for about 300,000 years [
42
,
46
]. From the standpoint of evolution, this amount of time may not be sufficient for full genetic adaptation to this novel mode of nutrition. In other words, it is possible that a raw diet that is free of artificial ingredients will improve mental abilities of modern humans. For convenience, we will refer to this diet as the “ancestral diet” throughout the book.

At this point some readers may have gotten the impression that this text is advocating abandoning all food safety guidelines and recommending a 100% raw food diet containing meat and fish. Please note that this book does
not
recommend this sort of diet.
^A
In particular, readers should avoid consuming raw animal foods such as raw meat, raw fish, or raw milk because these products carry a risk of serious infectious disease (Table 1 below). In my view, it is not necessary to subject oneself to this sort of risk in order to improve mental abilities. This book advances some arguments in favor of diets that are safe and at the same time chemically similar to the ancestral diet. It is also possible to improve mental abilities by reducing food intake without following any strict diets, as you will see in the last section of this chapter.

Table 1.
Common pathogens that can occur in raw animal products. (To skip the table, press the skip button or
this link
.)
----------------------------------

Pathogen
:
Campylobacter jejuni
(bacterium)

Source
:
raw beef, poultry, and dairy

Symptoms of infection
:
abdominal pain, diarrhea, nausea, and vomiting