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Why Evolution Has Made It Difficult for Us to Wait for Our Marshmallows »

In my last essay I tried to make the case that delaying gratification was essentially good for us. Foregoing an immediate pleasure helped build our moral fibre, improving our resilience and ultimately our satisfaction with life.

[Psychologists call our ability to delay gratification in this way our intertemporal utility function. I have often wondered whether my inability to wait until evening to have my first glass of wine might be called my intemperate utility function!]

In the interim I have been giving the matter a little more thought. In re-reading some of the material on evolutionary psychology it became apparent that, although it is our innate human desire to pursue happiness (or as I would prefer to couch it – to enhance our sense of well-being), Nature has little direct interest in our happiness.

[But I suspect the problem has been exacerbated also by modern technology. The science author, Robert Wright asserts, “Technologies of distraction have made attention deficits more common.” If, as I suspect and Buddhism teaches, well-being requires a certain focus of mind, then this would certainly be a factor impeding our quest for well-being.]

To put it bluntly, Nature views us as biological machines whose prime purpose is to pass on our genes to future generations. Natural selection has no concern about our psychological or social welfare except to the extent that these characteristics impede or enhance our capacity for gene replication. It is more concerned with our physical well-being because that has a greater correlation with our potential fecundity.

That humanity might be driven (almost mindlessly one might say) in this way by Nature took some time to be appreciated. The human ego was self-interestedly inclined to propagate the myth of human freedom and the dominance of mind over environmental and biological determinants in shaping human behaviour. As the social sciences began to develop in the early twentieth century a doctrine began dominating the field that biology doesn’t matter much and that the uniquely malleable human mind had severed our behaviour from its evolutionary roots. As Emile Durkheim, the father of modern sociology wrote, “Human nature is merely the indeterminate material that the social factor moulds and transforms.”

Over coming decades these views would be challenged not just by the work of evolutionary theorists but also by the findings of geneticists and anthropologists. As Robert Wright observed in his book The Moral Animal:

….today’s Darwinian anthropologists, in scanning the world’s peoples, focus less on surface differences among cultures than on deep unities. Beneath the crazy quilt of rituals and customs, they see recurring patterns in the structure of family, friendship, politics, courtship, morality. They believe the evolutionary design of human beings explains these patterns: why people in all cultures worry about social status (often more than they realise); why people in all cultures not only gossip but gossip about the same kinds of things; why in all cultures man and women seem different in a few basic ways; why people everywhere feel guilt, and feel it in broadly predictable circumstances; why people everywhere have a deep sense of justice, so that the axioms “One good turn deserves another” and “An eye for an eye and a tooth for a tooth” shape human life everywhere on this planet.

In this way Darwinian evolutionists identify that human nature has been shaped over the eons by those factors that have enduringly aided not only survival but gene replication in subsequent generations.

Of course many have objected that the rapid growth of the human brain, the addition of the front temporal lobes which enhanced our ability to reason and our growing awareness of our (self) consciousness, provided us with tools to stand above evolutionary processes and determine our own behaviour more readily.

But such a belief is misguided. These developments would not have occurred unless they helped fulfil evolution’s primal aims of survival and procreation. To a layperson, it may seem natural that the evolution of reflexive, self-conscious brains would liberate us from the base dictates of our evolutionary past. However an evolutionary biologist would contend that these new human capacities, far from freeing us from evolution’s mandate to survive and reproduce, equips us to do it more effectively.

Let us hear again from Robert Wright on the issue.

…….as we evolve from a species whose males forcibly abduct females into a species whose males whisper sweet nothings, the whispering will be governed by the same logic as the abduction – it is a means of manipulating females to male ends and its form serves this function. The basic emanations of natural selection are refracted from the older, inner parts of our brain all the way out to its freshest tissues. Indeed the freshest tissue would never have appeared if it didn’t toe the natural selection’s bottom line.

Now one of the simplest strategies evolution has co-opted in this process is the use of pain and pleasure. In the short term we are repelled by those things that are dangerous to our existence or impede our reproductive capacity and we gain pleasure from those things that (in the short term at least) enhance our prospects of survival and procreation.

As the biologist George Romanes put it in 1884, twenty five years after the publication of Darwin’s The Origin of the Species:

Pleasures and pains must have been evolved as the subjective accompaniment of processes which are respectively beneficial or injurious to the organism, and so evolved for the purpose or to the end that the organism should seek the one and shun the other.

Evolution is essentially a slow process. It is the biological lessons of generations upon generations that are finally embedded in our genetics. Human-like animals (hominids) have been on earth for fifteen million years or more which has given evolution a reasonable opportunity to impose itself on the development of humanity.

We consistently underestimate the broad and pervasive influence of our genetic inheritance. As Leda Cosmides and John Tooby wrote in Evolutionary Psychology: A Primer:

       the mind is a set of information –processing machines that were designed by natural selection to solve adaptive problems faced by our hunter-gatherer ancestors.



The phenomena of consciousness (or self-consciousness, if you like) has only been present in hominids for something in the order of one hundred thousand years (some scientists argue even less). In evolutionary terms it is a very late arrival. Most of the instinctual responses we have learnt to aid our survival were laid down well prior to that. As a result it is also likely that the pains and pleasures we feel, and that were once useful for our survival may no longer be appropriate.

Let me give you a trite example. Most of us have instinctual fears of snakes and spiders. Yet most of us wouldn’t know of anyone who has died of a snake bite or a spider bite. But in that long period of time when our ancestors were hunter-gatherers, snakes and spiders posed a real threat. It was therefore a good evolutionary strategy to have an inbuilt fear of snakes and spiders. Today we would be better served to have an innate fear of electricity sockets, speeding motor vehicles and (particularly in the USA) guns. But these are relatively recent developments which evolutionary adjustments are yet to catch up with.

Moreover the physiological responses of flight or fight were useful strategies, for example, when the environment threatened immediate physical harm and dangers were prevalent. Then life was short and these physical responses aided us significantly in avoiding premature death. In modern societies, where the environment is much more benign and life spans are significantly enhanced, the physiological triggers of those physical response mechanisms can lead to hypertension and various cardiovascular diseases that now paradoxically reduce our life spans.


Let us now turn our attention to the pleasures that evolution has co-opted to do its work.

An array of human behaviours that advance evolutionary purposes might include meeting such goals as eating and drinking sufficiently, copulating, impressing peers and overcoming rivals.

It is evident that evolution is well served if such activity serves to bring pleasure. But the catch, of course, is that these pleasures are short-lived and it is not hard to see why. If the pleasure didn’t subside we wouldn’t seek it again. If our desired meal satisfied us for a long period of time we would then go without eating and perhaps jeopardise our physical well-being, which would impair our propensity to procreate.

And most of us have sometimes experienced the short term pleasure to be gained by besting our rival. Within a little while it seems such an insignificant thing.

Or what about that outcome we sought to enhance our status? Perhaps it was a job promotion or purchasing a luxury car. How long did we bask in the pleasure of that attainment? Not too long to be sure.

But evolution has as its prime outcome the replication of our genes. The pleasure of sexual gratification would certainly seem to aid that goal. Yet again the pleasure of sexual intercourse soon wanes. What use would it be for evolution if a single act of coition satisfied our sexual desires? Evolutionary processes are facilitated by repeated couplings.

In short, under the sway of evolutionary processes we are driven to do things that are encouraged by the pleasure we derive from doing so. But because the pleasures we derive from these activities are short lived we are destined to mount the “hedonistic treadmill” and pursue them over and over even though they have little impact on our long-term sense of well-being.

I have now given you a theoretical evolutionary platform to ponder. It is time to return to the marshmallows.

It was difficult for our hunter-gatherer ancestors to find enough sustenance. Eating too much would have seldom been a problem. No doubt on the occasion of a big catch, a successful hunt or when fruits they foraged for were in season they may occasionally have gorged themselves. What’s more, by and large, the foods they consumed were probably better for them than the processed foods full of salt, sugar and saturated fats which are prevalent in our diets.

But because of their circumstances the hunter-gatherers had to be opportunistic and avail themselves of any opportunity to eat that presented itself to them.

The first time you eat a marshmallow and you taste its delicious sweetness you will be rewarded with a sense of pleasure emanating from a dopamine hit provided by your brain chemistry. Interestingly modern research suggests that after you have become a confirmed marshmallow eater the dopamine hit you get from anticipation of eating the marshmallow becomes stronger than the effect you get from actually consuming it. And when you have consumed your marshmallow pretty soon, in anticipation of having another you will be reaching into the bag for more. This will occur whether your body will benefit from further consumption or not.

So those children who were tempted by a marshmallow by that dastardly researcher, were more than likely responding to their genetic inheritance in availing themselves of the immediate opportunity to take a dopamine hit without thought of the future opportunities, (“a bird in the hand so to speak”).

But that throws up the challenge of explaining why some children would resist the temptation for an additional reward even if postponed.

Now even if we concede the huge impact our biological inheritance has on our lives, we should not discount the impact of socialisation. As some of my readers last week attested, growing up in families that had experienced some degree of privation encouraged frugality and an ability to understand that overindulgence in the present may jeopardise well-being in the future. These are values and attitudes we learn early in life and our family environment and the example of our parents has a marked impact on how we in turn behave.

It is impossible for us not to be impacted by our genes but our instinctual tendencies can be tempered by our social learning. I would submit that this is the most likely explanation for some of the children in the research cited being able to delay gratification. They probably belonged to families who valued restraint and “putting something aside for a rainy day”. (Or maybe the sceptics might say they just didn’t like marshmallows!) But surely prudent consumption and the ability to accumulate expand later options. The on-going benefits they experienced for such self-control should be a prompt to reinforce the value of good parenting.