A Computer Simulation Of The Evolution Of Suicide Based On The Sexual Penna Model

From an evolutionary perspective, suicide is a paradoxical phenomenon given its fatal consequences on one's reproductive fitness. Some theorists proposed that suicide is an evolutionary stable strategy which can be evolved through kin-selection. Some other theorists constructed it as an ultimate maladaptive behavior in response to "crushing defeats" in domains of great evolutionary imports. Studies support both theories. By using conventional methods alone it would be hard for researchers to discriminate between these hypotheses.In this article, in order to investigate whether committing suicide under serious sick conditions could be evolved through kin-selection, the sexual Penna model was modified, and then the evolutionary process of suicide was simulated. The following results were found:First, when D=0～0.04, suicide could not be evolved. It only had some small effects on the survival rates and mortality of the population, and it had no effects on the number of family members of the population.Second, when D=0.05, suicide could be evolved, it was as adaptive as non-suicide, and it also showed some other benefits and costs.Third, when D=0.06～1.0 suicide could easily be evolved. And under specific parameter values, it showed other specific benefits and costs.In conclusion, in combine with results obtained by other researchers, this study suggests that the cause of modern human suicide behavior is due to an ancient and evolved mental mechanism which is still functioning.