The research reported here was designed to explore the relationship between aversive visual stimuli and human physiological activity in a clssical conditioning situation. Specifically, the questions asked were (1) whether homicide pictures were effective stimuli in the classical conditioning of heart rate and electrodermal activity and (2) if conditioning occurred, what would be the form of the...

OBJECTIVE To examine whether state-level spending on social and public health services is associated with lower rates of homicide in the USA. DESIGN Ecological study. SETTING USA. PARTICIPANTS All states in the USA and the District of Columbia for which data were available (n=42). PRIMARY OUTCOME MEASURE Homicide rates for each state were abstracted from the US Department of Justice Fed...

a r t i c l e i n f o We propose Homicide Adaptation Theory as a new explanation for why people kill. Multiple homicide mechanisms have evolved as effective context-sensitive solutions to distinct adaptive problems. Killing historically conferred large fitness benefits: preventing premature death, removing cost-inflicting rivals, gaining resources, aborting rivals' prenatal offspring, eliminati...

BACKGROUND Risk factors for homicide are emerging; however, the predictive value of IQ, for which there is a strong prima facie case, has yet to be examined. AIMS To examine the association between IQ and risk of death by homicide. METHOD A cohort of 968 846 men, aged 18-19 years, were administered an IQ test battery at military conscription and then followed for mortality experience over t...