One possibility is that actual executions affect a potential murderer’s subjective probability of being executed if he commits the crime. If this is the rationale for the exercises, then Texas is not the ideal context for a study because executions are sufficiently routine in Texas that one would expect the informational content of a specific occurrence to be low. Yet because of the state’s high fraction of executions nationally, Texas data are frequently used for studies. Texas might have experienced changes in the execution sanction regime, which would be useful for identifying deterrent effects, but this perspective has not been systematically explored, despite some occasional references to regime shifts in Texas.9 In this respect, we think that the focus on Texas in the time-series literature may be misguided.
Another behavioral framework under which these exercises are informative is one in which an execution renders the possibility of the punishment more salient to a potential murderer. But such a framework would appear to imply that the effects of an execution will exhibit heterogeneity across types of potential murderers. For example, when murder is a crime of passion, one might argue that executive mental functioning is impaired. Hence, in this case salience comes into play because of a diminished capacity in thinking about consequences. Alternatively, one could argue that the impairment is such that the consequences of the action do not affect choice. This example illustrates that the implications of salience claims are far from obvious. Furthermore, we are unaware of any work that directly addresses salience as a source of deterrence and does so in a way that respects the fact that one needs a model of behavior, whether of the rational choice type or not, to interpret statistical findings.
Finally, we note that it is not even clear that executions per se are the source of salience. Is it obvious that actual executions are the main source of salience of the death penalty rather than, say, highly publicized death sentences? How do changes in the law or Supreme Court decisions affect salience? In the committee’s search of relevant studies, we did not find any in which the sources of salience were explored. Hence, although it is a perfectly logically coherent idea that executions make capital punishment salient and provides a deterrence effect for this reason, there is no empirical work to justify the claim. One of the recommendations in Chapter 6 will involve the collection of data on perceptions of sanction regime, which would facilitate such empirical work.
Another distinct problem with the time-series studies is that they do
9 Land, Teske, and Zheng (2009) should be commended for distinguishing between periods in Texas when the use of capital punishment appears to have been erratic and when it appears to have been systematic. But they fail to integrate this distinction into a coherently delineated behavioral model that incorporates sanctions regimes, salience, and deterrence. And, as explained above, their claims of evidence of deterrence in the systematic regime are flawed.