Van Hezewijk, R. (2003). Psychology and evolutionary biology; Causal analysis, evidence, and nomothetic laws. In N. Stephenson, L. Radtke, R. Jorna, & H. J. Stam (Eds.), Theoretical psychology; Critical contributions (pp. 405-415). Concord, Ontario: Captus Press. Since James, some psychologists have referred to evolutionary theory as one of the sources of explaining behavior (James, 1890). However, the status of such references is not always clear. In the recent work of many authors, 1 it is not always clear (1) what kind of causal analyses are appropriate in psychology beyond those psychologists already use; (2) how psychological explanations fit in the general scheme of explanations in the life sciences, especially in biological explanatory schemes; and (3) what this implies for the evaluation of available evidence. This chapter is about these questions. I discuss five types of explanations involved in psychological explanations using an evolutionary perspective, and I discuss how these types of analysis relate to types of propositions and types of evidence.

When mediators are not experimentally manipulated, estimates of mediation effects are likely to be biased. This is so even when the analyzed data are free from measurement error, reciprocal causality, and other problems that have attracted attention since the publication of . We demonstrate the bias mathematically and show, in a content analysis of recent articles, that it is likely to affect many published studies of mediation. We propose two new methods of mediation analysis, both of which require manipulation of mediators. These methods are more difficult to implement than nonexperimental approaches, but they produce unbiased estimates of mediation effects, and the success that psychologists have already had manipulating mediators suggests that they are often feasible. * We thank

Psychological Inquiry, 2002

Lloyd and Feldman's (this issue) continuing commentary on our recent target article and rejoinder focuses on two overarching issues. First, Lloyd and Feldman claim that our description of the core metatheoretical assumptions of modern evolutionary theory overemphasizes the role of inclusive fitness (i.e., the so-called selfish gene approach) at the expense of underemphasizing important alternative approaches (e.g., multilevel selection models, gene-culture coevolution models). Second, Lloyd and Feldman criticize some of the methods and assumptions that ostensibly characterize the evolutionary psychology research program. These criticisms concern the conceptualization of organisms as inclusive fitness maximizers, the soundness of the epistemology of evolutionary psychology, the modularity of psychological mechanisms, and the universality of psychological mechanisms. In the first part of this rejoinder, we acknowledge that different schools of thought exist regarding the plausibility and importance of various metatheoretical assumptions in human evolutionary psychology. We argue that to date, however, only the gene-centered adaptationist program (consistent with inclusive fitness theory) has demonstrated scientific progressivity by generating a coherent, integrated body of new knowledge and explaining away several apparent anomalies. In the second part of this rejoinder, we discuss several misunderstandings that underlie Lloyd and Feldman's criticisms of human evolutionary psychology.

2002

Lloyd and Feldman's (this issue) continuing commentary on our recent target article and rejoinder (Ellis & Ketelaar, 2000; Ketelaar & Ellis, 2000) focuses on two overarching issues. First, Lloyd and Feldman claim that our description of the core metatheoretical assumptions of modern evolutionary theory overemphasizes the role of inclusive fitness (i.e., the so-called selfish gene approach) at the expense of underemphasizing important alternative approaches (e.g., multilevel selection models, gene-culture coevolution models). Second, Lloyd and Feldman criticize some of the methods and assumptions that ostensibly characterize the evolutionary psychology research program. These criticisms concern the conceptualization of organisms as inclusive fitness maximizers, the soundness of the epistemology of evolutionary psychology, the modularity of psychological mechanisms, and the universality of psychological mechanisms. In the first part of this rejoinder, we acknowledge that different schools of thought exist regarding the plausibility and importance of various metatheoretical assumptions in human evolutionary psychology. We argue that to date, however, only the gene-centered adaptationist program (consistent with inclusive fitness theory) has demonstrated scientific progressivity by generating a coherent, integrated body of new knowledge and explaining away several apparent anomalies. In the second part of this rejoinder, we discuss several misunderstandings that underlie Lloyd and Feldman's criticisms of human evolutionary psychology. The Role of Inclusive Fitness Theory in Evolutionary Psychology Lloyd and Feldman (this issue) criticize our reference to inclusive fitness theory as providing the foundation of modern evolutionary theory:

Trends in Ecology & Evolution, 2001

Psychological Inquiry, 2000

Lloyd and Feldman's (this issue) continuing commentary on our recent target article and rejoinder focuses on two overarching issues. First, Lloyd and Feldman claim that our description of the core metatheoretical assumptions of modern evolutionary theory overemphasizes the role of inclusive fitness (i.e., the so-called selfish gene approach) at the expense of underemphasizing important alternative approaches (e.g., multilevel selection models, gene-culture coevolution models). Second, Lloyd and Feldman criticize some of the methods and assumptions that ostensibly characterize the evolutionary psychology research program. These criticisms concern the conceptualization of organisms as inclusive fitness maximizers, the soundness of the epistemology of evolutionary psychology, the modularity of psychological mechanisms, and the universality of psychological mechanisms. In the first part of this rejoinder, we acknowledge that different schools of thought exist regarding the plausibility and importance of various metatheoretical assumptions in human evolutionary psychology. We argue that to date, however, only the gene-centered adaptationist program (consistent with inclusive fitness theory) has demonstrated scientific progressivity by generating a coherent, integrated body of new knowledge and explaining away several apparent anomalies. In the second part of this rejoinder, we discuss several misunderstandings that underlie Lloyd and Feldman's criticisms of human evolutionary psychology.

Psychological Inquiry, 2002

Given the recent explosion of interest in applications of evolutionary biology to understanding human psychology, we think it timely to assure better understanding of modern evolutionary theory among the psychologists who might be using it. We find it necessary to do so because of the very reduced version of evolutionary theorizing that has been incorporated into much of evolutionary psychology so far. Our aim here is to clarify why the use of a reduced version of evolutionary genetics will lead to faulty science and to indicate where other resources of evolutionary biology can be found that might elevate the standard of the evolutionary component of evolutionary psychology.

Organizational Research Methods, 2010

Experimental tests of assumed mediation models have been recommended by numerous methodologists. However, they may prove problematic for a number of reasons. Thus, this article considers (a) experimental designs that can be used in tests of mediation, (b) problems that may arise in manipulating mediator variables, (c) distributional issues in experimental tests of mediation, (d) statistical approaches for testing mediation models, including strategies for testing for direct versus indirect effects in experimental tests of mediation models, and (e) a set of conclusions stemming from our analysis.

Psychological Science, 2004

Evolutionary psychologists argue that human nature contains many discrete psychological adaptations. Each adaptation is theorized to have been functional in humans' ancestral past, and empirical evidence that an attribute is an adaptation can come from showing it possesses complexity, efficiency, universality, and other features of special design. In this article, we present a tutorial review of the evidentiary forms that evolutionary psychologists commonly use to document the existence of human adaptations. We also present a heuristic framework for integrating and evaluating cross-disciplinary evidence of adaptation. Pregnancy sickness, incest avoidance, men's desires for multiple sex partners, and an easily learned fear of snakes are evaluated as possible human adaptations using this framework. We conclude that future research and teaching in evolutionary psychology would benefit from more fully utilizing crossdisciplinary frameworks to evaluate evidence of human adaptation.

Since evolutionary psychology and behavioral ecology have much in common despite their using different objects for their study, one might expect these disciplines to share a common conceptual framework with associated definitions. Unfortunately, such agreement does not entirely exist. To address the problem, we propose a common, conceptual framework, the Adaptive Behavioral System (ABS), which organizes behavior within an evolutionary framework around an organism's life history tasks. An ABS includes strategies that use decision rules and employs tactics administered by a hypothesized construct, the Evolved Processing Unit (EPU). The ABS also includes observed or predicted behavior which can be tested experimentally -the ultimate test of construct validity. Use of the proposed framework should help the two disciplines focus on their common, core business of behavior and, ultimately, be to the benefit of both.