The importance of being able to concentrate on abstract thinking and tasks with little sensory feedback has increased significantly in modern times relative to the importance of peripheral awareness. In the EEA, peripheral awareness was crucial for detecting predators and enemies, while an ability to exclude other stimuli had few applications. We may hence have evolved attention systems with a tendency to be too easily distracted in a modern setting. It has been suggested that ADHD is a form of “response-readiness” that was more adaptive in past environments (Jensen et al. 1997). Concentration enhancers may therefore be feasible and promising in modern settings, enabling users to meet high demands for sustained attention. Drugs such as methylphenidate (Ritalin) are already used to treat ADHD and occasionally also for enhancement purposes (Farah et al. 2004).
Dietary Preferences and Fat Storage
One tradeoff involving food availability relates to the question of how much nutrition the body should store in fatty deposits. If high-calorie foods are scarce and food availability highly variable, it is optimal for an individual to crave high-calorie foods and to store lots of energy in fat deposits as insurance against lean times. We still need an appetite today, and we still need fat deposits, but—at least in the developed world—they are much less important now than in the past. Many people’s natural set points of appetite and body fat are higher than optimal, leading to increased morbidity. In wealthy modern societies, where a Mars bar is never far away, the risks of obesity and diabetes outweigh the risk of undernutrition (Fontaine et al. 2003), and a sweet tooth is maladaptive.
This suggests that it might be possible to enhance human health by finding effective ways to downregulate our cravings for fat and sugar or by reducing the absorption and storage of these calories in fatty tissues. Such an enhancement might take various forms: nutritional advice, diet pills, artificial sweeteners, indigestible substances that taste like fat, weight-loss clubs, hypnotherapy, and, in the future, gene therapy. The evolution heuristic suggests that our natural proclivities to consume and store nutrients might be a case where we could benefit from going against the wisdom of nature. Independent considerations and possibly further research would be needed to determine the most effective way of doing this, given that weight loss itself is a longevity risk factor (Gaesser 1999) and that those who are mildly overweight have lower mortality than those who are underweight or obese (Flegal et al. 2005). Possibly an aversion to unhealthy foods and eating habits would be more effective and safer than a general downregulation of appetite. The heuristic tells us only that there are no general “wisdom of nature” reasons to retain our current bodyweight set points; it does not by itself tell us which approaches to changing them would be safest.