This article reviews efforts to assess the effectiveness of television programs on changing health behaviors. The relatively limited literature to date has featured primarily correlational studies which permitted no causal conclusions. The few experimental studies available present a mixed picture. Numerous methodologic problems beset any effort at assessment of effectiveness. Perhaps the greatest difficulty is operationalizing a design that permits true experimental manipulation on a relevant sample without contamination. The several methodologic problems and some potential means of surmounting them are discussed.

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This is an open-access article distributed under the terms of the Creative Commons AttributionNonCommercial 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted use, distribution, and reproduction in any medium for non-commercial purposes, provided the original author and source are credited, a link to the CC License is provided, and changes -if any -are indicated.© Abstract. Genetics underpins many ways in which individuals differ. The purpose of this paper is to advance a model with testable hypotheses regarding the cause of the genetic basis of personality. We proceed by developing the suggestion that diversity in personality genes evolved to constrain parasitic elements of culture and discuss its implications. In particular, a critical test of this hypothesis is whether personality genes show fluctuating linkage disequilibrium and a dispersed distribution throughout the genome. It is further suggested that this Red Queen process has facilitated the evolution of intelligence and allowed a higher mutation rate in relevant genes. The model's empirical predictions are discussed in the context of alternative explanations, including those regarding intragenomic conflict, economics, and heterozygote advantage.