Population heterogeneity and state dependence: State of the evidence and directions for future research

Criminological research has consistently uncovered a positive correlation b etween past and current criminal behavior. Continuity in offending over tim e can be attributed to at least two processes-population heterogeneity and state dependence. A population heterogeneity process attributes stability i n offending over time to differences in an anti-social characteristic (self -control, impulsivity, psychopathic personality) across persons that is est ablished early in life and time-stable thereafter. An implication of a popu lation heterogeneity explanation for continuity in offending over time is t hat the anti-social characteristic is likely to have reverberations through out life, taking many manifestations later in life (unemployment, drug addi ction, marital instability). Any observed correlation between these later l ife events and criminality, therefore, is spurious rather than causal, due to the fact that they are all the effects of a common cause. A state depend ence explanation, in contrast, attributes observed stability in criminal of fending to a process of contagion. That is, criminal behavior has a genuine causal effect on subsequent criminality by eroding constraints and strengt hening incentives to crime. The implication of a state dependence process i s that criminal conduct may be influenced by later life events. In this pap er, we draw a connection between population heterogeneity and state depende nce processes and extant criminological theory. We also review the literatu re that has investigated the plausibility of these two processes. Finally, concluding that we know very little about them we make recommendations for future research on population heterogeneity and state dependence.