by Julie C. Driebe
Intelligence shapes many aspects of our everyday life. It is, for example, a robust predictor of health, income and social status. However, human brains seem too costly and complex to have evolved for mere survival. For example, our intelligence enables us to create art, literature, or engage in humorous wordplay. A well-known theory therefore proposed that our extraordinary intelligence could serve as an indicator of genetic quality and was therefore preferred in prospective partners, thus evolved not only through natural but also sexual selection. Moreover, the theory proposes that humour could function as an intelligence display. Supporting this theory, past research has established that, cross-culturally, intelligence is considered a highly attractive trait in hypothetical long-term mates. However, it is less clear whether actual, objectively assessed intelligence is indeed found attractive when evaluating prospective partners, particularly in face-to-face contexts.
The aim of the current study was to test whether measured intelligence is indeed perceived and found attractive in potential mates by members of the opposite sex and whether funniness could be an intelligence display. To answer our research questions, we used two complementary approaches: an elaborate rating design (study 1) and a more ecologically valid speed-dating study (study 2).
In study 1, we objectively measured the intelligence of 88 target men using eight intelligence subtests. Results of cognitive ability tests are substantially intercorrelated, yielding a latent, general factor of intelligence, referred to as the g factor. These target men were then rated on their intelligence, funniness, physical attractiveness and mate appeal by 179 women. Women in different sets rated different traits. One set of women rated men’s physical attractiveness, based on a facial and full-body photograph. Another set of women rated men’s funniness and intelligence after watching short video clips of men performing several tasks. These tasks were selected to include cues related to men’s intelligence. For example, one task was to read out newspaper headlines aloud, which has been found to enable accurate intelligence perception. In the most complex condition, women provided ratings of men’s mate appeal several times: First, after they saw a facial and full-body photograph, second after watching a video of men pronouncing vowels (which included information on vocal attractiveness but not intelligence), third, after men read out newspaper headlines and finally, a video, in which men were asked to make the experimenter laugh.
In study 2, 763 participants took part in 2-5 speed-dates and interacted with members of the opposite sex for 3 minutes. After each interaction, participants rated each other on their mate appeal, intelligence and funniness. Once all speed-dates and ratings had been completed, participants filled out the post-questionnaire including their assessment of their partner’s verbal intelligence.
Results of both studies suggested that intelligence can be accurately perceived after viewing short video clips, even net of attractiveness halo effects, and after participating in short interactions. However, only perceived intelligence, not measured intelligence, was associated with mate appeal. Similarly, only perceived and not measured intelligence was related to funniness. The main predictor of mate appeal was physical attractiveness.
These findings cast doubt on the theory that intelligence evolved as a fitness indicator through good genes sexual selection, since intelligence would have needed to be found attractive as soon as it can be perceived to effectively sift through many potential mates (i.e., providers of genetic benefits). Further, funniness does not seem to advertise intelligence since we found no association of funniness and measured intelligence. We found that only perceived intelligence and not measured intelligence predicted mate appeal. That perceived intelligence is found attractive could explain why intelligence is often listed as a desirable trait for hypothetical partners. Nevertheless, intelligence could play a role at later stages of long-term relationship formation, as intelligence is a potent predictor of direct mate choice benefits, including resource provision, social status, problem solving skills, and being a competent cooperation partner. We believe that we investigated the research question with complementing studies in which drawbacks of one study were addressed by strengths of the other study. In addition, an independent recent speed dating study found highly consistent results. However, future studies should follow courtships over longer timespans than initial contact.