Sexual orientation as a modulator of aggression, cooperation, and empathy

• Applicants: Dr. Katrin T. Lübke; Professorin Dr. Bettina M. Pause
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: from 2014 to 2017
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 254419391

Evolutionary theories of homosexuality regard it as an adaptive trait. Several of these theories focus the formation and maintenance of intrasexual alliances. Heightened empathy and cooperation as well as reduced aggression, specifically in same-sex encounters, are discussed as key adaptive traits in homosexual individuals. Research so far has yielded some data on intrasexual differences within these features, namely higher trait empathy and reduced physical aggression in homosexual compared to heterosexual individuals. These results, however, are based solely on self-reports. To date, studies utilizing physiological parameters or behavioral sampling are missing, as are paradigms that allow distinguishing between intra- and intersexual interaction. Thus, the here proposed project aims to examine differences between homosexual and heterosexual individuals regarding aggressive and cooperative behavior on one hand, and physiological indicators of empathy (mu-suppression, facial mimicry measured with facial EMG) on the other hand. Both within- and between-gender interactions will be examined. It is hypothesized that homosexual men and women compared to heterosexual individuals of the same gender will respond with less aggressive behavior to provocation by a same-sex individual. Further, it is expected that homosexual men and women compared to heterosexual individuals of the same gender will show a higher tendency for reciprocal cooperation in same-sex encounters. Within an EEG paradigm, the participants will be presented with pictures of male and female hands and feet in painful situations. It is hypothesized that the mu activity above primary sensorimotor cortex areas will show a stronger reduction in homosexual individuals compared to heterosexual individuals of the same gender when watching same-sex individuals in pain. Mu suppression is linked to mirror neuron activity in primary sensorimotor areas, and is regarded as a correlate of empathy. Similarly, the extent of facial mimicry in response to emotional facial expressions is associated with empathy. Facial mimicry can effectively be assessed using facial EMG measurements. We expect more pronounced mimicry of same-sex individuals in homosexual men and women compared to heterosexual individuals of the same gender.

• DFG Programme: Research Grants