Self-sacrificial behaviours like those seen in honeybees and ants may hold the key to find out whether human suicides have evolutionary roots, reveals a study.Thomas Joiner, professor of psychology at the Florida State University, led a team of researchers to examine scientific knowledge and drawing parallels between suicide in humans and the self-sacrificial behaviours of colony-like -- or eusocial -- species such as shrimp, mole rats and insects. The researchers theorised that humans exhibit the characteristics of eusocial species such as relying on multi-generational and cooperative care of young and utilising division of labour for successful survival.
"Humans are a species that is eusocial, and that's an important starting point," Joiner said, adding: "That suggests a certain set of characteristics, including some really striking self-sacrifice behaviours." Those eusocial behaviours, understood as part of what is called inclusive fitness in evolutionary biology, are adaptive."The idea is if you give up yourself, which would include your genes, it can be evolutionarily speaking 'worth it' if you spare or save multiple copies of your genes in your relatives," Joiner said. "It's a net benefit on the gene level."However, when the researchers looked at human suicide in a modern context, they surmised that suicide among humans represented a derangement of the self-sacrificial aspect of eusociality."If you can identify animal models for this behaviour and understand its circuitry at the neurochemical and neurophysiological levels, then it might lead to new insights about similar circuitry that fail in human suicide," Joiner said.The study findings were recently published in the journal Psychological Review.