Saturday, March 5, 2016

Sexual Selection: Humor - Males vs. Females

Sexual selection is a mode of natural selection where typically members of one biological sex choose mates of the other sex with whom to mate. There is usually competition between members of the same sex to sexually reproduce with members of the opposite sex. In humans, health, intelligence, social status, physical attractiveness and confidence are some examples of sexually selected traits. Recently, there have been studies done showing that humor may also be a sexually selected trait. In this post, I will further discuss these studies, how the definition of humor differs between the two sexes (male and female), how it may differ among societies/cultures, and whether or not it can be considered a trait of sexual selection. 

Study #1: Production and Appreciation of Humor as Sexually Selected Traits
 According to a study published by researchers in 2006, both men and women preferred someone with a 'good sense of humor.' What did that mean? Did that mean that both men and women preferred funny partners? Did they prefer a partner who would laugh at their jokes? Well, the objective of this study was to define that term for men and women. The researchers created a questionnaire containing 14 statements. The questionnaire included three subgroups:
  1. The importance of a relationship partner’s good sense of humor (6 items)
  2. The importance of a relationship partner’s receptivity to the participant’s own humor (4 items)
  3. The importance of a relationship partner’s production of humor (4 items)
Participants rated their agreement on a seven-point scale (1=strongly disagree, 4=neither agree nor disagree, 7=strongly agree). They were then given two other questionnaires for further analysis of the participants' preferences. First, they read two scenarios/situations where they hypothetically met someone in one of three different locations: a bus, a cafeteria and a bar. They were then asked to choose to put the two individuals in a category: one night stand, long-term partner, short-term partner, a date, or a friendship. An example of one of the scenarios is:
"Please imagine that you are taking the bus to school, and that an attractive young woman (man) you have never met before strikes up a conversation with you. You talk about school, which classes you are taking, and what you might do after you graduate. You have a very friendly conversation with her (him), and she (he) jokes around with you. There are several times when something she (he) says makes you laugh. When you make joking comments, she (he) does not laugh that much at your jokes. You obviously haven’t offended her (him) with your comments, it simply seems that they don’t seem to suit her (his) sense of humor. When the bus comes to your stop, you both exchange phone numbers, and you consider whether you will call her (him) or not."
In each scenario, one individual was receptive to the participant’s own (hypothetical) humor but also produced humor the participant did not enjoy. The individual in the other scenario produced humor the participant enjoyed but was not receptive to the participant’s humor. In the above example, the individual produced humor that the subject 'enjoyed', but did not laugh or was not receptive to the participant's joke.
The results of "the categorization questionnaire (the rating scale questionnaire) suggest that women value a partner who can produce humor and who is receptive to their own humor, whereas men value only a partner’s receptivity to their own humor." However, during their scenario-based questionnaires, women valued humor production, whereas men valued receptivity to their humor. Only when evaluating women for just friendship purposes, men showed a more direct preference for humor production. This exception is understandable when it comes to sexual selection. If a man is looking for a friendship (strictly) with a woman, they are most likely not trying to impress, attract, or compete for them in terms of reproduction, relationship, dating, etc. In this case, they don't mind whether or not the woman finds them funny, but they prefer that the woman can also bring her humor to the table when hanging out. This study suggests that women tend to prefer a partner who has a 'good sense of humor' (someone who can make them laugh), and men generally prefer a partner who will be receptive, or laugh at their jokes.

Study #2: Sex Differences in Preferences for Humor: A Replication, Modification, and Extension
One study does not solely prove that humor is a sexually selected trait. There also may be biases and confounding variables that may alter or skew the data. Fortunately, other scientists have modified, extended and tried to replicate Study #1. Replicating or trying to verify experiments/studies only further proves or can disprove the existing hypotheses. Researchers from the Department of Psychology at the University of Miami published a study that tried to replicate the 2006 study (Study #1). They also included modifications and extensions to the study. First, they conducted a replication of Study #1 (one of the initial studies that reported on sex differences in humor). Second, they modified the original methods of Study #1 to verify the scale used to measure sex differences, and lastly, they used methods from other researchers who have also worked on this concept, to find the extent to which men and women view humor production and appreciation as luxuries (something that would be nice but not needed or exactly preferred) versus necessities (something they would prefer a partner to have) when selecting a long-term romantic partner.
Study #2 sample size consisted of 83 ethnically diverse individuals: 38 men and 45 women. The researchers gave the same questionnaires with the same scaling method to the participants as Study #1 (replication). They then gave participants a questionnaire that was not included in Study #1. This questionnaire was a modification to the original study. Participants were told to imagine a world in which they could purchase traits to design an ideal long-term romantic partner. The traits provided were:
  1. Makes me laugh
  2. Finds me humorous
The participants were given a budget and for each dollar they spent on their ideal long-term partner, the percentile of their partner went up by 10% in that specific category. For example, if the participant spent $6.00 on 'makes me laugh,' then their ideal long-term partner would have a 60% in that category. If the participant added another $4.00 into 'makes me laugh', then the partner's total percentage would be 100% (the highest in that category). Another modification that the researchers in Study #2 added was that they gave a new questionnaire and changed the factor scale of Study #1's 14 statement questionnaire. They got rid of the 'importance of a partner's sense of humor (6 items)' and focused more solely on production of humor in a partner and the receptivity of the partner's own humor. The researchers in Study #2 did this so that they could eliminate any biases and confusion toward the definition 'sense of humor.' Sense of humor could mean a variety of things to an individual, and controlling for any confounding variables and/or biases in a study is always ideal.
The researchers found (modified version of the first questionnaire with the rate scale) that men showed a significant preference for: their partner’s receptivity to their own humor rather than their partner’s ability to produce humor. Women also showed a significant preference for: their partner’s receptivity to their own humor at a similar rate to their partner's ability to produce humor. However, compared to men, women preferred their partner's ability to produce humor more than their partner's receptivity to their own humor. The researchers also factored in whether or not the type of relationship was important (just like Study #1). They found that in long-term relationships and on a date, women preferred (more than men) that their potential partner would be a humor producer. When asked about short-term relationships, one night stands, and friendships, both men and women did not differ proportionally about whether they preferred a partner who could produce humor. A possibility for this is that when looking for a potential long-term partner, a woman/man will factor in traits such as good health, creativity, confidence, etc. The reason why is because if there are possible 'good' heritable traits that could be passed on to potential offspring, then that would be preferable rather than passing on 'unfavorable' traits. Even if there isn't a potential offspring (to pass on genes), women prefer a man who can produce humor and men prefer a woman who will laugh or be receptive to their humor for competitive reasons. For long-term relationships or dates that lead to a long-term relationship, if a man knows that they found a partner who is attracted to and laughing at their jokes, then they know that the woman is interested in them, their humor, their creativity, etc. Similarly, if a woman finds a long-term partner who is able to make them laugh, then they can assume that their partner is interested in keeping them entertained and intrigued in the relationship. Both women and men have a pretty low preference of humor production for partners who are short-term, one night stands, or just for friendship. This may be due to the fact that there is no long-term effort/time or competition to keep that partner around.
In the budget experiment, the researchers found that at their lowest budget size of $5.00, men spent a larger percentage of their money on a partner’s humor receptivity than did women. At their budget of $10.00, men continued to spend a larger percentage of their money on a partner’s humor receptivity than did women. The researchers note that the proportion spent on humor receptivity in the low and medium budgets did not differ for men, but increased for women. At their largest budget of $15.00, men again spent more on a mate’s humor receptivity than did women. The researchers concluded that more robust sex differences came about once subjects were asked to make trade-offs. When asked to select either a humor producer or humor appreciator in long-term relationships/dates, women chose humor producer more often than humor appreciator. Women's preference for a humor producing mate was not as clear when asked for short-term partners. Women found humor production more of a necessity and humor receptivity more of a luxury, whereas men found humor receptivity more of a necessity and humor production more of a luxury.
Limitations: Researchers stated that their subjects were young college students and may not have had much experience with relationships/dating. 

 Non-Western Study
To consider 'humor' as a sexually selected trait in humans, these behaviors associated with humor production and receptivity of humor among men and women must be very similar or the same throughout cultures. As of now, we can only assume that men who produce humor and women who are receptive to their potential partner's humor are ideal in a Western culture (especially among younger individuals). There is few cross-cultural research published today, so we cannot be definite when stating that "humor" is a sexually selected trait. One study conducted by researchers on Tsimane women in Bolivia:
"Participants were 101 women, aged 14–70 years, living in four separate communities situated along the Maniqui, Cuverene, and Apere rivers. The four communities chosen for the study varied in their acculturation, proximity, and contact with the market economy outside Tsimane territory. The sample included 29 women from one of the more acculturated villages (acculturation based upon market, health, and social exchange with Bolivian nationals), 36 and 14, respectively, from moderately acculturated villages, and finally, 24 women from a village of very low acculturation (101 total women). They were asked to participate in a questionnaire regarding social and behavioral qualities of other women living in their area. Ideally, to determine whether women were attempting to manipulate the reputations and attractiveness of others, behavioral observation on gossiping patterns would have provided the advantage of measuring actual behavior rather than reported opinions."
It is not a direct study to measure attractiveness of humor, but this study was designed to see whether assessments of personal characteristics affected judgments of women’s attractiveness by other women in a native community, and which characteristics were most related to attractiveness ratings. The variable 'humor' was predicted by the researchers to increase attractiveness reports, but, results found that it was not significantly related to the ratings of attractiveness. The researchers stated that one reason could be that humor may be a trait that women prefer more in males and, thus, may be unrelated to female judgments of female qualities and attractiveness. However, there is another explanation the researchers state that take into account the Tsimane culture and society. Humor may not have affected the rating (of how 'attractive' another woman is) because 'humor' in Tsimane groups revolve around making fun of others, and laughing at their expense. The researchers found that the perception on the question relating to humor seemed to vary and often was perceived as 'knowing how to make fun of others.' With this in mind, women may have seen being called 'humorous' as someone who was desired just as a friend and/or a person who would gossip behind someone else's back.

The different cultural/societal definitions of 'humor' can effect whether or not humor production or receptivity of humor can be noted as a sexually selective trait. If other cultures have a contextually different meaning for humor (someone who gossips), then being a humor producer in their society is not ideal when looking for a mate/relationship. This study shows that humor can be perceived differently (at least with the Tsimane people). 

Can Humor be a Sexually Selective Trait?
These studies and others show that both men and women (and possibly different cultures) define and prefer different types of humor Some studies suggest that these differences in the sexes - especially humor production - could be due to the fact that it reveals creativity, confidence, and possibly intelligence (although there haven't been many studies on intelligence and its relationship to humor, since intelligence is a complicated trait to measure). One study found (based on their results), that verbal humor (in men) was used in social situations and attracting mates. On average, men were funnier than women and because of that, men were signaling their mate quality through their humor ability. Women were more responsive to humor and because they were more likely to prefer a partner who can produce humor, men were more likely to be motivated to display their humor ability.
If we look at the studies done as of now, both young women and men (especially in a Western society) prefer their partner to have a 'good sense of humor.' Men prefer a partner who will be receptive towards their own humor and women prefer a partner who will produce humor. Because of that, men tend to be 'funnier' compared to women. Because men do not necessarily prefer a woman who can make them laugh or tell them jokes, women tend to be less funny because they do not have to be funny to attract a mate. On the other hand, because women prefer a mate who can produce humor, men are more 'pressured' to be funny. Thus, the reason why men tend to produce more humor than women (especially when attracting a long-term partner). Laughter stimulates both cognitive and emotional areas in the brain (reward system). For that reason, women might also look for a partner who can produce humor to stimulate those areas of the brain. If the woman wants to reproduce - because she must invest time in to having/raising the offspring (9 month pregnancy, birth, and breastfeeding) - she must be cautious when picking her mate. If her potential partner is funny and can produce humorous jokes/stories, then that shows her that her potential mate is confident, socially competent and creative. Genes that can be passed down to offspring (especially male offspring) and growing up with a father that possesses traits such as confidence, competence, creativity, intelligence, etc., can increase the likelihood of not only a 'good set of genes' being passed down, but also beneficial traits that can assist the offspring in the future when looking for/attracting a potential mate. Humor, although it doesn't seem as important as good health, fitness, etc., may actually be a factor in multiple different traits as listed above. 'Humor' may be a sexually selective trait, however, more studies need to be done (factoring in age and culture) to get closer to the truth.

Note: Further cross-cultural research and studies must be done to try to verify/produce findings to support humor as a sexually selective trait. Also, further studies should be done on older people to see if these hypotheses hold true when factoring in age. If questionnaires are handed out to participants, researchers must still consider biases and confounding variables and should control for as many variables as they can.

References + Related Links