Homicide Adaptation Theory

Introduction

The average lifespan in the United States in 2009 was 78 years old according to World Bank (2009). The risk of becoming a homicide victim is 1 in 287 over your lifetime (Duntley, Buss, 2011). There have been several theories developed to explain why murder occurs. One of the most famous theories is the Homicide Adaptation Theory (Duntley, Buss, 2011). This theory states that there have been recurring events and actions in humans where the fitness benefits associated with murder outweigh the fitness costs (Duntley, Buss, 2011). Another theory is the Byproduct Hypothesis that states murder is a byproduct that has evolved for non-deadly actions (Duntley, Buss, 2006). Although murder is a highly looked down upon and serious action

I find in my study that most murders are male to male interactions mostly due to the competition for a female or the male’s resources and possessions. The homicidal thoughts and fantasies correlate with life events such as cheating, low resources, and infanticide and result in the act of murder amongst many. I expected such results in this study after researching murder and the evolution of aggression in class originating with chimpanzees. However I did not expect people to view the benefits higher than the costs when murdering someone as you risk a lifetime in jail or the death penalty. Other cultures and countries may vary in costs associated with

More females were involved with infanticide as they have fewer years of fertile reproductive organs (Duntley, Buss, 2011). The five adaptive problems that involve women participating in infanticide are; avoiding investment in offspring with birth defects etc., avoiding investment in offspring where there are lack of resources or outside factors that limit or decrease the offspring’s survival, and getting rid of competition for their other offspring if there are limited resources (Duntley, Buss, 2011). This variable stimulated murder more so in women due to their investment in offspring is higher than a male (Duntley, Buss, 2011). With that being said, there could also be results of infanticide in males of this study. Males experience adaptive problems in infanticide such as; avoidance of investment of another man’s offspring, also known as a stepchild, ending investment for offspring they aren’t sure is theirs, and wanting to speed up his mate’s ovulation due to breastfeeding delaying it (Duntley, Buss, 2011).

Figure 1.3 represents the different relationships murder victims had with their killer. This data goes hand in hand with my study showing that most female victims were victims of other family members which could be due to infanticide by their parents. Female’s highest percentage of killers were partners or ex partners which could correlate with males