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My latest paper with Geoffrey Miller has just been published in the journal Intelligence, and I thought this would be a great opportunity to delve into the evolutionary basis of humor.
If you ask most people, they will tell you that they have a great sense of humor, definitely better than most others. In fact, studies have shown that more than 90% will say they have a good sense of humor (the rest probably didn't find the question amusing or didn't understand the question...).
Scientists have been trying to study humor from a variety of perspectives for decades, but only recently started to look at what might be the evolutionary roots of humor. Evolutionary explanations look at how a certain trait can enhance our overall fitness, and they can be divided into two types: either the trait increases our survivorship, or it can contribute to our reproductive success.
Of course, our behavior was shaped over millions of years of evolution, and the adaptive advantage that helped our ancestors to survive and reproduce may not confer the same advantage today. For example, eating food rich in calories and fat was very adaptive in environments in which food was scarce and unpredictable. In the western world today, these types of foods are abundant and cheap. People still have the tendency, shaped by our evolution, to eat as much of these foods as possible, which leads to maladaptive outcomes, such as obesity.
The current study (which is based on my dissertation) focused on the importance of humor in mating from an evolutionary perspective. Generally speaking, people with a sense of humor are very desirable to be around in social gatherings and especially as mates. However, men and women do not share the same preferences because the evolutionary forces that shaped men's and women's desires were not exactly the same. Sexual selection theory, one of Darwin's brightest ideas, states that among sexually reproducing species, the sex that invests more in the offspring will be choosier in picking a mate.
This asymmetry in parental care leads to strong intra-sexual competition among men, who try to impress the women with whom they are interested in mating. One way to do this is by having a lot of resources or money. Resources were valuable to women throughout our evolutionary history because they signaled the ability of the man to support his mate and their future children. Hence, high status men are considered more attractive in every society in the world.
But status isn't everything. One of the most desired traits when women are selecting a mate is intelligence. Intelligent is very valuable because intelligent people are more likely to succeed in life and gain resources and high status. In ancestral environments (or hunter-gatherer societies today) this can translate into being a good hunter. Today, it can manifest itself in many ways, and humor is one of them.
The ability to say something funny requires a high level of intelligence. If you memorize a thousand jokes, that doesn't make you a person with a sense of humor. Sense of humor is more subtle. A good sense of humor is about timing, the ability to say the funny thing at the right time and to the right people. Telling a sexist joke in a room full of women will probably not score many points with the audience. Humor is largely an interpersonal activity that requires a high level of emotional, social and also mating intelligence (see this book for more).
Sense of humor is therefore a good indicator of intelligence. Geoffrey Miller built on sexual selection theory and offered the theory of mental fitness indicators. According to this theory, some human capacities such as language, creativity, art, music, and humor evolved at least partly to signal intelligence. These abilities are sexually attractive because they are hard to fake indicators of intelligence, and potentially could also indicate that the person showing them carries good genes.
Now, while this fitness indicator theory works for both sexes, since women are the choosier, we can expect that they will be more sensitive to these cues and place more importance on them when choosing a mate.
In regards to humor, research shows very clearly that women value humor ability in a mate more than men. This is one of the top three traits that consistently show up in surveys of women's mate preferences. In personal dating ads for example, women requested dates with a sense of humor at least twice as often as men did.
This makes perfect sense if humor is indeed an indicator of mate quality, because we expect women to be more susceptible to this type of signal. Other studies provide support that women prefer to be on the receptive side of humor. Women, for example, tend to laugh and smile more during conversations, especially when men are around or in response to humor produced by men.
The goal of our study was to further test key components of this theory. First, we tested whether there are actual sex differences in the ability to produce humor. Most humor studies focus on appreciation of humor, largely because it is much easier to give people a set of jokes and ask them to rate them. Relatively few studies have looked at humor production ability and very few of those tested sex differences in humor ability.
If humor is a sexually selected trait, and women look for it more than men as a signal for intelligence, we can expect that men will be better at producing humor since they are competing against other men for the attention of women.
If men do not view women's sense of humor as an important virtue and it doesn't play an important role in their mate selection, women should not develop humor ability as much as men. Second, we wanted to see how this humor ability may be related to intelligence and will it translate into actual mating success.
To do so, we employed large samples of 200 men and 200 women with an average age of about 21. All of them were college students that receive credit for their participation. While a sample of college students may not represent the whole population, and these samples are often used because of convenience, for questions related to sexual selection they make for a perfect population. College students are in their peak fertility, and at the age where they compete the most over mates.
How to measure a sense of humor?
One of the important aspects of the study was to pick a good measure of humor creativity. This is not an easy task, as there are many forms of humor that people use. Most people have an intuitive sense of what sense of humor is, even if they can't really define humor. To a certain degree, humor is subjective. How many times have you heard that you "had to be there" in order to understand what was so funny? You can also think that something is funny, or see the humor in it, without laughing or smiling (especially when you are alone), so is that still humor? These are deep questions that researchers are still pondering. Nonetheless, humor is also at least partially objective (for example, a successful sitcom) and this was the focus of our study.
What we did was to give people cartoons without any captions, similar to the ones you find in The New Yorker cartoon caption contest. Subjects viewed several cartoons and were instructed to write as many funny captions that they could think of in ten minutes. Later, we had six judges rate all these captions (and there were close to 5,000 of them!) for funniness on a scale from 1-7 (1 = not funny at all, 7 = very funny).
True, this measure does not look at the interpersonal aspect of humor, but I think it was a pretty good way to separate between people who have a good sense of humor from those who do not. In fact, we chose to use this measure to try to eliminate the possibility that social and other external cues would influence the judges. Judges were students around the same age of the subjects, with similar cultural backgrounds so they would be in the best position to assess the jokes.
In addition, we gave our subjects two tests of intelligence, one that is called Raven's Advanced Progressive Matrices, which measures abstract reasoning. The other was a test of verbal intelligence, where subjects had to identify the meaning of words. Both tests are considered very reliable and measure different aspect of intelligence.
Lastly, we asked participants to report various aspect of their sexual behavior. We created two scales that capture two major aspects of mating. One, actual mating success, which includes questions about the age of their first sex, how many partners they had in the past year and in their lifetime, acts of intercourse in the past month and the number of one night stands. The second scale captures what we call pro-promiscuity attitudes toward sex. This scale included questions about the likelihood of them being involved in casual sex or whether they think that sex without love is ok, how many sex partners they think they will have in the next five years, and other items to measure attitudes toward casual sex.
Results:
First, let's look at the cartoon captions. Overall, most of the captions were not very funny. You can try coming up with funny captions to The New Yorker cartoon caption contest and see for yourself that this is not an easy task. Nonetheless, consistent with our hypothesis, we got modest to strong sex differences. Men, on average, produced a larger number of captions and, more importantly, funnier ones. This might represent two things: men are funnier than women on average, and they also try harder to be funny. Granted, we did not test all possible uses of humor and focused only on verbal humor, but the differences were significant and consistent.
Now, I am not saying that women do not have a sense of humor. It is important to remember that we are dealing with averages, and there is a lot of variability in the ability to produce humor. In fact, we got many funny captions from women, albeit fewer than from men.
Next, we tested whether there is a relationship between humor ability and intelligence. Not surprisingly, we found a correlation between funniness and intelligence, such that funny people were more intelligence on average, and this was true for both sexes. Also, and again not surprisingly, there was a stronger relationship between humor ability and verbal intelligence and less so with abstract reasoning. Our measure of humor focused on verbal humor, so this makes sense. Maybe different types of humor will yield other correlations.
Regarding mating and sex, we found very interesting results. First, men reported having on average more sexual partners than women, which is a statistical impossibility (who were they having sex with?). That is a mystery, since men would never exaggerate their sexual reputation, right? To be fair, the men in the study were slightly older, and women also tend to underestimate their own number of sexual partners. Men also expressed more interest in casual sex, and this is also to be expected from other studies, with a strong evolutionary basis for this as well. Women are more likely to avoid sex with strangers that might result in a pregnancy with a man that will not be around for long. Men and women started having sex around the same age (between16 and 17), and there is much more variability in the number of sex partners for men.
Second, and more important for the purposes of our study, humor ability seems to be translated into actual sexual behavior. In other words, participants that were funnier reported having more sex, having more sexual partners, started having sex earlier in life, and so on. When we looked at the complex relationships between humor, intelligence and sexual behavior, we found that humor ability strongly mediates the positive effects of intelligence on mating success. In other words, humor is an indicator of intelligence that turns into mating success.
Interestingly, we did not find any sex differences in this aspect, meaning that it works well for both men and women. Funny women also can enjoy the benefits of a great sense of humor if they are interested in it. But this scenario is less likely to happen on average, since remember that women showed lower average humor production ability. In addition, the motivation to reap the benefits of humor is different for men and women. Since men are the ones that try to impress women, for the most part, they also use humor more frequently, especially when women are around. As the choosiest sex, women, on the other hand, do not have to try very hard to impress the men, and therefore likely use humor less frequently. But if they do use humor, they could potentially gain the same advantage. You also have to remember that humor is a risky strategy sometimes. People may want to impress others using humor, but many just fall flat and actually hurt their chances with bad jokes that do not impress the other sex.
