The Case Against Free Will

What a Quiet Revolution in Psychology has Revealed about How Behaviour is Determined

David Lieberman

• Publisher: Palgrave Macmillan
• Year: 2016
• ISBN:
  9781137345257
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

Do judges' decisions depend on how long it is since they ate their lunch? Is the best place for a woman to seduce a man on a rickety bridge? Does free will really exist? This book explores how our genes and experiences determine our behaviour as well as discussing the implications determinism may have on personal responsibility and morality.

Part I

Evidence

1

Sex and Violence

In the Prologue I suggested that our behaviour is powerfully influenced—perhaps even totally determined—by our genes and experiences. I’ve already looked at a few examples, but the determinist claim is deeply counterintuitive, and so rightly demands strong supporting evidence before it can be taken seriously. I cannot cover all that evidence here, but I will sample it by focusing on just two questions: Why do we find some men and women sexually attractive? And why are some men violent? You might think that sexual attraction and violence are both areas where free will reigns supreme—no one makes us violent, no one makes us fall in love with someone; we choose freely. But in this chapter I will consider evidence that our choices may be less free than we imagine.

Sexual attraction

I’ll begin with sexual attraction, starting with why men find some women more attractive than others. At first glance, ideals of feminine beauty seem to vary widely. In Western culture, for example, Rubens’ paintings suggest that men in his time preferred large, voluptuous women, whereas now there is a greater emphasis on slimness. There is also considerable variation between men: some prefer large women, some slim; some tall and some short; and so on. It seems a classic case of free will, with each man deciding for himself what shape he finds attractive.

Female shape

The first study to seriously challenge this view was the work of a psychologist at the University of Texas, Devandra Singh. He believed that underneath the apparent diversity in male ideals of female beauty there might be some preferences that are universal. Specifically, he was interested in the relationship between the size of a woman’s waist and the size of her hips (her waist-to-hip ratio [WHR]). His hypothesis was that men prefer women with relatively narrow waists and broad hips, and that this preference might be almost universal across time and culture. (We’ll consider the basis for his prediction shortly.)

To find out, he began by comparing the measurements of Miss America contest winners and Playboy playmates over seven decades, from 1923 to 1990. As he had predicted, the WHRs proved remarkably constant. Among Playmates it varied between only 0.68 and 0.71, and among Miss America winners between 0.69 and 0.72. To assess the desirability of this shape further, he also obtained measurements from fashion models. In general they were far thinner than, say, Playmates, but their WHRs proved to be virtually identical, varying only between 0.68 and 0.69. Even Twiggy, the most famously thin model of all time (her nickname hints at her appearance), had a WHR of 0.73. Moreover, this preference was not confined to Americans, as similar preferences were subsequently reported across a range of societies, including highland tribes in Papua New Guinea, students in China and men in New Zealand. The ideal female body shape, in other words, was impressively constant, with little variation over time or across cultures.¹

The importance of the WHR does not mean that other factors are not significant. Popular culture, for example, would suggest that breast size is also important, and there is experimental evidence to support this. In one neat study, a female confederate of the experimenter sat in a nightclub for an hour. The larger her breast size (manipulated by the bra she wore), the more often she was approached by men.² In another study, men were shown photographs of women and the experimenters tracked their eye movements as they looked at the photos. Men spent more time looking at the women’s breasts than at any other part of their bodies, though when later asked to rate each woman’s attractiveness, their ratings were influenced far more by her WHR than by the size of her breasts.³ The WHR is not the only determinant of a woman’s attractiveness but it is clearly an important one.

An obvious question is why this should be—why should men so often converge on this one shape as their ideal? As we’ve seen, Singh had anticipated this result, and his prediction was based on theories of how human behaviour evolved. According to these evolutionary accounts, men want partners who are fertile, because fertile women will produce more children and thus make it more likely that the men’s genes will be passed on. But how can a man tell if a woman is fertile?

One of the best clues, it turns out, involves the WHR. The hormone oestrogen controls where fat is deposited in a woman’s body, increasing the deposit of fat at the hips and reducing its deposit at the waist. Oestrogen also plays a vital role in fertility. A woman with a small waist and large hips, in other words, is likely to have higher levels of oestrogen in her body, and thus is also more likely to produce children. This prediction has been confirmed: women with this shape are more likely to become pregnant, and they are also more likely to conceive after artificial insemination.

Now suppose that there was a gene that led men to prefer this shape. Men with this gene would produce more children, and so over many generations the proportion of men preferring this hourglass shape would increase. Each of these men would be convinced that his attraction to women with this shape was a completely free choice, but in fact it would have been shaped by thousands of years of evolution—at a conscious level a free choice, but powerfully driven by his genes.

Male shape

Singh’s research also spawned interest in what male shape is most attractive to women. The first point to note in addressing this question is that women appear to be far less influenced by body shape than men. According to evolutionary theorists, women have to invest far more in a child than men—in carrying a foetus and then in rearing a child after it is born—and so it is particularly important for them to select a mate who will be strongly committed to her, and thus remain present throughout the child’s life. Evolutionary theorists thus predicted that women would be less influenced by men’s appearance and more by clues suggesting commitment and wealth (and thus the ability to support a child). In one test, women were shown photos of a man seated in a car, either a very expensive Silver Bentley or a far less expensive Ford Fiesta. The women rated the man in the Bentley as much more attractive. When men were shown equivalent pictures of a woman, the car had no effect on their rating of her attractiveness.⁴ Men seem more concerned with a woman’s fertility, women with a man’s ability to support her and her children.

Insofar as women are influenced by a man’s shape, however, the single most important factor seems to be the shoulder-to-hip ratio, with broader chests and shoulders having greater appeal.⁵ Here, too, women may be responding to an evolutionary clue to a man’s fertility: Men with this shape have been found to have higher testosterone levels, and they begin having sex at an earlier age.

The face

An obvious determinant of attractiveness is the face, and some of the factors that influence attractiveness are also obvious. A face with smooth, unblemished skin, for example, is more attractive than one with blemishes. However, research has revealed other influences that are far less obvious. Perhaps the most surprising finding concerns facial symmetry. If you drew a vertical line down the middle of a person’s face, through their forehead, nose and mouth, you would discover that while the left and right halves are similar, they are not identical. (One ear might be larger than another, one eye might be closer to the midline and so on.) The degree to which the two sides are similar is called symmetry, and studies have shown that people find symmetrical faces significantly more attractive than asymmetrical faces. In one such study, a computer was used to modify photographs of faces in order to make them more symmetrical. When participants in the study were shown both versions, 96 per cent found the symmetrical faces more attractive than the original. Moreover, this preference may be innate. When newborn infants, just one or two days old, were shown photographs of faces, they spent more time looking at attractive faces than unattractive ones.

People seem unaware of how strongly facial symmetry influences them—it seems unlikely that you have ever heard anyone say: ‘Wow, what a symmetrical face!’ To explore this, participants in one study were asked what aspects of the faces they had viewed had influenced their judgements. Answers ranged from the eyes looking kind to the person looking grumpy, but only one person out of 40 mentioned symmetry. So why do we have an unconscious attraction to symmetrical faces? The answer, yet again, may be that these faces provide a clue to a person’s biological fitness. The symmetry of a face depends on conditions in the womb as the foetus grows. If conditions are suboptimal—insufficient nutrients, say, or exposure to pollution—the two sides are less likely to develop symmetrically. By looking at a person’s face, therefore, we potentially obtain valuable information about their health, and there is some evidence to support this. In one intriguing study, men with symmetrical faces were found to produce not only more sperm but also better sperm, capable of swimming faster. And if we consider facial attractiveness more broadly, not just confining our attention to symmetry, there is evidence that men with attractive faces produce more children. There could be many reasons for this, but symmetrical faces do appear to signal a man or woman’s reproductive fitness, and evolution seems to have instilled in us an unconscious attraction to these faces.⁶

Arousal

Yet another unconscious determinant of sexual attraction was suggested in a study carried out in a highly unusual setting for a psychology experiment: a deep river gorge in British Columbia. There were two ways of crossing the river: a narrow, wobbly footbridge located some 230 feet above rapids, or a much more substantial wooden bridge only 10 feet above a small rivulet. As they crossed either bridge, men were approached by an attractive woman who asked if they would answer some questions for a research project she was conducting. When the interview was over, she gave the men her telephone number in case they later had any questions.

The real purpose of the study was to measure sexual attraction—would the men later phone to ask for a date? Many did, but the study’s striking finding was that the proportion asking for a date depended on where the interview took place: half the men interviewed after crossing the rickety bridge later phoned for a date, compared with only 12 per cent of those interviewed after crossing the solid bridge.

On the surface, this result might seem bizarre—why should the location of the interview determine whether men think a woman is attractive? However, Dutton and Aron (1974) had predicted precisely this result on the basis of a theory of emotion which proposes that all emotions are characterized by similar states of physiological arousal—increased heart rate, rapid breathing and so on. We therefore need to rely on environmental cues to help us identify what emotion we are experiencing. According to this theory, men would have experienced strong arousal when crossing the high bridge; when they encountered the attractive interviewer, they would have unconsciously thought: ‘Aha, it must be her beauty that is making me feel so excited.’ Believing that they were attracted to her, they would have been more likely to ask her for a date.

An alternative explanation might have occurred to you—namely, that the results were due to differences in the kinds of men who used the two bridges. Perhaps the higher bridge attracted men who were more adventurous and thus would also have been less timid about asking for a date. To control for this possibility, Dutton and Aron ran a second experiment. All the interviews were now conducted with men who had crossed the high bridge, but one group was interviewed immediately after crossing and the other only after a 10-minute delay. The interviewer was no less attractive when she approached men after the delay, and yet the timing of the interview profoundly affected how they perceived her: when it took place immediately, the men were far more likely to phone her later to ask for a date. The most likely explanation seems to be that the men who crossed the high bridge misinterpreted their arousal, attributing it to sexual attraction rather than to the more prosaic experience of crossing a rickety bridge. When they later decided to ask for a date, they almost certainly believed this to be a free choice, but they were being influenced by factors of which they were entirely unaware.⁷

The evidence we’ve been reviewing does not prove that we have no free will. It does suggest, though, that judgements of attractiveness are based on a range of environmental and genetic factors, some of which influence us without our awareness.

Violence

We turn now to the question of violence, and especially physical violence. What is it that makes some individuals far more violent than others?⁸

Heredity

Our review of the evidence on sexual attraction immediately suggests one possible factor—namely, heredity. Do some of us have genes that predispose us to violence? And if such genes exist, how important are they, or, put another way, to what extent can heredity explain why some people are more violent than others?

One way to try to answer this question is to compare violent behaviour in identical twins and fraternal twins. Identical twins come from a single egg that has split in two after fertilization, so that both of the new eggs have exactly the same genes. Fraternal twins, on the other hand, come from different eggs fertilized by different sperm, and thus differ in their genetic composition. Insofar as genes are important in violent behaviour, identical twins should display the same behaviour—if one twin is violent, there should be a strong likelihood that the other twin will be too. And that is what researchers have found. In general, our genes seem to account for roughly 50 per cent of the tendency towards violence, though in one study the effect was even stronger. Laura Baker and her colleagues looked at antisocial behaviour in children, using criteria such as whether the children involved bullied other children, physically attacked them, set fires or were cruel to animals. They studied 1,210 pairs of twins, and found that the genes the child carried accounted for 96 per cent of the variation in which children became antisocial, a remarkable statistic.⁹ Knowing the child’s genetic background, they could predict with almost perfect accuracy whether they would become antisocial. Research like this has made it clear that heredity plays a major role in the genesis of violence.

As discussed in the Prologue, we already know one of the genes involved, the one that regulates the production of the enzyme MAOA. One form of this gene leads to lower-than-normal levels of MAOA, and men who possessed this form of the gene and were also abused as children were six times more likely to be convicted of violent crimes.

Our genes are clearly important, but they are not the whole story: the MAOA gene on its own did not cause aggression; it was only when combined with a history of abuse that violence increased. So, what environmental factors are now known to be important? We’ll look at a few.

Smoking during pregnancy

You might think that the most important environmental de...