Evolution and medicine: the long reach of "Dr. Darwin"

In this review we consider the new science of Darwinian medicine. While it has often been said that evolutionary theory is the glue that holds the disparate branches of biological inquiry together and gives them direction and purpose, the links to biomedical inquiry have only recently been articulated in a coherent manner. Our aim in this review is to make clear first of all, how evolutionary theory is relevant to medicine; and secondly, how the biomedical sciences have enriched our understanding of evolutionary processes. We will conclude our review with some observations of the philosophical significance of this interplay between evolutionary theory and the biomedical sciences.     

Animal experimentation: The legacy of Claude Bernard

Claude Bernard, the father of scientific physiology, believed that if medicine was to become truly scientific, it would have to be based on rigorous and controlled animal experiments. Bernard instituted a paradigm which has shaped physiological practice for most of the twentieth century. In this paper we examine how Bernard's commitment to hypothetico‐de‐ductivism and determinism led to (a) his rejection of the theory of evolution; (b) his minimalization of the role of clinical medicine and epidemiological studies; and (c) his conclusion that experiments on non‐human animals were, “entirely conclusive for the toxicology and hygiene of man”. We examine some negative consequences of Bernardianism for twentieth century medicine, and argue that physiology's continued adherence to Bernardianism has caused it to diverge from the other biological sciences which have become increasingly infused with evolutionary theory.     

Determining whether causal order affects cue selection in human contingency learning: Comments on Shanks and Lopez (1996)

Shanks and Lopez (1996) reported three experiments in which they attempted to test whether causal order affects cue selection, and concluded that it does not. Their study provides an opportunity to highlight some basic methodological criteria that must be met in order to test whether and how causal order influences learning. In particular, it is necessary to (1) ensure that participants consistently interpret the learning situation in terms of directed cause-effect relations; (2) measure the causal knowledge they acquire; (3) manipulate causal order; and (4) control the statistical relations between cause and effect. With respect to these criteria, each experiment reported by Shanks and Lopez fails on multiple counts. Moreover, several aspects of the results reported by Shanks and Lopez are explained by causal-model theory, but not by associative accounts. Their study thus adds to a growing body of evidence from different laboratories indicating that human contingency learning can be guided by causal interpretation.     

The "What" and "Why" of Goal Pursuits: Human Needs and the Self-Determination of Behavior

Self-determination theory (SDT) maintains that an understanding of human motivation requires a consideration of innate psychological needs for competence, autonomy, and relatedness. We discuss the SDT concept of needs as it relates to previous need theories, emphasizing that needs specify the necessary conditions for psychological growth, integrity, and well-being. This concept of needs leads to the hypotheses that different regulatory processes underlying goal pursuits are differentially associated with effective functioning and well-being and also that different goal contents have different relations to the quality of behavior and mental health, specifically because different regulatory processes and different goal contents are associated with differing degrees of need satisfaction. Social contexts and individual differences that support satisfaction of the basic needs facilitate natural growth processes including intrinsically motivated behavior and integration of extrinsic motivations, whereas those that forestall autonomy, competence, or relatedness are associated with poorer motivation, performance, and well-being. We also discuss the relation of the psychological needs to cultural values, evolutionary processes, and other contemporary motivation theories.     

Domain-specific reasoning: social contracts, cheating, and perspective change.

What counts as human rationality: reasoning processes that embody content-independent formal theories, such as propositional logic, or reasoning processes that are well designed for solving important adaptive problems? Most theories of human reasoning have been based on content-independent formal rationality, whereas adaptive reasoning, ecological or evolutionary, has been little explored. We elaborate and test an evolutionary approach. Cosmides' (1989) social contract theory, using the Wason selection task. In the first part, we disentangle the theoretical concept of a "social contract" from that of a "cheater-detection algorithm". We demonstrate that the fact that a rule is perceived as a social contract--or a conditional permission or obligation, as Cheng and Holyoak (1985) proposed--is not sufficient to elicit Cosmides' striking results, which we replicated. The crucial issue is not semantic (the meaning of the rule), but pragmatic: whether a person is cued into the perspective of a party who can be cheated. In the second part, we distinguish between social contracts with bilateral and unilateral cheating options. Perspective change in contracts with bilateral cheating options turns P & not-Q responses into not-P & Q responses. The results strongly support social contract theory, contradict availability theory, and cannot be accounted for by pragmatic reasoning schema theory, which lacks the pragmatic concepts of perspectives and cheating detection.     

Andrew Shanks,German Idealism,and the Speculative Redemption of Theodicy

In this review essay I discuss and critically evaluate the neo-Hegelian theologian Andrew Shanks’ Theodicy Beyond the Death of ‘God’ with regard to its central argument of the theological adequacy of the composite theodicy funded by Hegel, Jacob Boehme (1575-1624) and F. W. J. Schelling and also its highly individual theological style. While I commend Shanks’ impulses to enlarge the Hegelian discourse by speculative discourses that are more mythopoetic, especially given Shanks’ long-standing interest in the critical and constructive power of poetry, I consider it to be an open question not only as to whether Shanks has sustained his case for the theological adequacy of the composite theodicy, but whether this composite speculative matrix has the capacity to enlist the prophetic discourses of both the Bible and modern poetry that Shanks thinks it has. In addition, while Shanks’ theological style is a unique blend of disciplined analysis with a more hortatory rhetoric, as rendered in this his latest book, the generally polemical tone and the tendency to dismissive judgments not only regarding particular philosophers and theologians, but also particular forms of historical Christianity such as Roman Catholicism, compromise – if not entirely invalidate – its repeated message of inclusion.     

A further look at the "language-as-fixed-effect fallacy".

The proper analysis of experiments using language materials has been a source of controversy and debate among researchers. We summarize the main issues and discuss the solutions that have been presented. Even though the major issues have been dealt with extensively in the literature, there still exists quite a bit of confusion about how to analyze the data from such experiments. We discuss a number of the most frequently voiced objections. In particular, we discuss the issue of what happens if in a counterbalanced design only some of the items show the treatment effect. Finally, a possible solution is discussed for the case where only partial matching of items between conditions is possible.     

Children,childhood, and development in evolutionary perspective

We examine children, childhood, and development from an evolutionary perspective. We begin by reviewing major assumptions of evolutionary–developmental psychology, including the integration of “soft” developmental systems theory with ideas from mainstream evolutionary psychology. We then discuss the concept of adaptive developmental plasticity and describe the core evolutionary concept of developmental programming and some of its applications to human development, as instantiated in life history theory and the theory of differential susceptibility to environmental influence. We then discuss the concept of adaptation from an evolutionary–developmental perspective, including ontogenetic and deferred adaptations, and examine the development of some adaptations of infancy and childhood from the domains of folk psychology and folk physics. We conclude that evolutionary theory can serve as a metatheory for developmental science.     

Evolution, selection and cognition: from "learning" to parameter setting in biology and in the study of language

Most biologists and some cognitive scientists have independently reached the conclusion that there is no such thing as learning in the traditional "instructive" sense. This is, admittedly, a somewhat extreme thesis, but I defend it here in the light of data and theories jointly extracted from biology, especially from evolutionary theory and immunology, and from modern generative grammar. I also point out that the general demise of learning is uncontroversial in the biological sciences, while a similar consensus has not yet been reached in psychology and in linguistics at large. Since many arguments presently offered in defense of learning and in defense of "general intelligence" are often based on a distorted picture of human biological evolution, I devote some sections of this paper to a critique of "adaptationism," providing also a sketch of a better evolutionary theory (one based on "exaptation"). Moreover, since certain standard arguments presented today as "knock-down" in psychology, in linguistics and in artificial intelligence are a perfect replica of those once voiced by biologists in favor of instruction and against selection, I capitalize on these errors of the past to draw some lessons for the present and for the future.     

Longing for Life Extension: Science Fiction and Late Life

Rejuvenescence has long been a topic of legend and medicine. As the body became the property of medical science, speculative fiction asked how fantastic experiments with bodies would affect the life course. In science fiction, medical breakthroughs promise or threaten to forestall or even reverse the decline from midlife through old age to senility and decrepitude. Responding to debates over evolution, eugenics, and scientific experimentation with human and animal subjects, rejuvenescence novels such as Bruce Sterling's Holy Fire (1996) ask readers whether they desire long life or heightened quality of life; the consolations of age or the hungers of youth; short-lived intensity or perpetual ennui.     

The Primary Processes: A Preliminary Exploration of A-Rational Mentation from an Evolutionary Viewpoint

In this article we investigate research on nonhuman animal cognition revealing the predominance of primary processes-like operations that are effective and adaptive from an evolutionary perspective. But first and from a different direction, we review a body of recently popular empirical work on human heuristics and biases that proposes System 1 and System 2 as a dual-process model of cognition and emotion; this without acknowledging Freud’s primary and secondary processes. Thus, we explore the parallels between primary process and System 1, as we evaluate the case for the evolutionary nature of primary process. We guide the reader through literature on animal cognition and that of System 1 biases and heuristics to provide the psychoanalytic reader with the opportunity to make important links to psychoanalytic concepts.     

"Pray for those who mistreat you": effects of prayer on anger and aggression

Although some religious teachings have been used to justify aggression, most religious teachings promote peace in human affairs. Three experiments tested the hypothesis that praying for others brings out the more peaceful side of religion by reducing anger and aggression after a provocation. In Experiment 1, praying for a stranger led provoked participants to report less anger than control participants who thought about a stranger. In Experiment 2, provoked participants who prayed for the person who angered them were less aggressive toward that person than were participants who thought about the person who angered them. In Experiment 3, provoked participants who prayed for a friend in need showed a less angry appraisal style than did people who thought about a friend in need. These results are consistent with recent evolutionary theories, which suggest that religious practices can promote cooperation among nonkin or in situations in which reciprocity is highly unlikely.     

Bayesian contour integration.

The process by which the human visual system parses an image into contours, surfaces, and objects--perceptual grouping--has proven difficult to capture in a rigorous and general theory. A natural candidate for such a theory is Bayesian probability theory, which provides optimal interpretations of data under conditions of uncertainty. But the fit of Bayesian theory to human grouping judgments has never been tested, in part because methods for expressing grouping hypotheses probabilistically have not been available. This paper presents such methods for the case of contour integration--that is, the aggregation of a sequence of visual items into a "virtual curve." Two experiments are reported in which human subjects were asked to group ambiguous configurations of dots (in Experiment 1, a sequence of five dots could be judged to contain a "corner" or not; in Experiment 2, an arrangement of six dots could be judged to fall into two disjoint contours or one smooth contour). The Bayesian theory accounts extremely well for subjects' judgments, explaining more than 75% of the variance in both tasks. The theory thus provides a far more quantitatively precise account of human contour integration than has been previously possible, allowing a very precise calculation of the subjective goodness of a virtual chain of dots. Because Bayesian theory is inferentially optimal, this finding suggests a "rational justification," and hence possibly an evolutionary rationale, for some of the rules of perceptual grouping.     

Rethinking temporal contiguity and the judgement of causality: effects of prior knowledge, experience, and reinforcement procedure.

Time plays a pivotal role in causal inference. Nonetheless most contemporary theories of causal induction do not address the implications of temporal contiguity and delay, with the exception of associative learning theory. Shanks, Pearson, and Dickinson (1989) and several replications (Reed, 1992, 1999) have demonstrated that people fail to identify causal relations if cause and effect are separated by more than two seconds. In line with an associationist perspective, these findings have been interpreted to indicate that temporal lags universally impair causal induction. This interpretation clashes with the richness of everyday causal cognition where people apparently can reason about causal relations involving considerable delays. We look at the implications of cause-effect delays from a computational perspective and predict that delays should generally hinder reasoning performance, but that this hindrance should be alleviated if reasoners have knowledge of the delay. Two experiments demonstrated that (1) the impact of delay on causal judgement depends on participants' expectations about the timeframe of the causal relation, and (2) the free-operant procedures used in previous studies are ill-suited to study the direct influences of delay on causal induction, because they confound delay with weaker evidence for the relation in question. Implications for contemporary causal learning theories are discussed.     

Asymmetries in cue competition in forward and backward blocking designs: Further evidence for causal model theory

A hallmark feature of elemental associative learning theories is that multiple cues compete for associative strength when presented with an outcome. Cue competition effects have been observed in humans, both in forward and in backward blocking procedures (e.g., Shanks, 1985) and are often interpreted as evidence for an associative account of human causal learning (e.g., Shanks & Dickinson, 1987). Waldmann and Holyoak (1992), however, demonstrated that cue competition only occurs in predictive, and not diagnostic, learning paradigms. While unexplainable from an associative perspective, this asymmetry readily follows from structural considerations of causal model theory. In this paper, we show that causal models determine the extent of cue competition not only in forward but also in backward blocking designs. Implications for associative and inferential accounts of causal learning are discussed.     

Normality and naturalness: A comparison of the meanings of concepts used within veterinary medicine and human medicine

This article analyses the different connotations of “normality” and “being natural,” bringing together the theoretical discussion from both human medicine and veterinary medicine. We show how the interpretations of the concepts in the different areas could be mutually fruitful. It appears that the conceptions of “natural” are more elaborate in veterinary medicine, and can be of value to human medicine. In particular they can nuance and correct conceptions of nature in human medicine that may be too idealistic. Correspondingly, the wide ranging conceptions of “normal” in human medicine may enrich conceptions in veterinary medicine, where the discussions seem to be sparse. We do not argue that conceptions from veterinary medicine should be used in human medicine and vice versa, but only that it could be done and that it may well be fruitful. Moreover, there are overlaps between some notions of normal and natural, and further conceptual analysis on this overlap is needed.     

From covariation to causation: a test of the assumption of causal power

How humans infer causation from covariation has been the subject of a vigorous debate, most recently between the computational causal power account (P. W. Cheng, 1997) and associative learning theorists (e.g., K. Lober & D. R. Shanks, 2000). Whereas most researchers in the subject area agree that causal power as computed by the power PC theory offers a normative account of the inductive process. Lober and Shanks, among others, have questioned the empirical validity of the theory. This article offers a full report and additional analyses of the original study featured in Lober and Shanks's critique (M. J. Buehner & P. W. Cheng, 1997) and reports tests of Lober and Shanks's and other explanations of the pattern of causal judgments. Deviations from normativity, including the outcome-density bias, were found to be misperceptions of the input or other artifacts of the experimental procedures rather than inherent to the process of causal induction.     

Are animal models predictive for humans?

It is one of the central aims of the philosophy of science to elucidate the meanings of scientific terms and also to think critically about their application. The focus of this essay is the scientific term predict and whether there is credible evidence that animal models, especially in toxicology and pathophysiology, can be used to predict human outcomes. Whether animals can be used to predict human response to drugs and other chemicals is apparently a contentious issue. However, when one empirically analyzes animal models using scientific tools they fall far short of being able to predict human responses. This is not surprising considering what we have learned from fields such evolutionary and developmental biology, gene regulation and expression, epigenetics, complexity theory, and comparative genomics.     

Evolutionary consumer psychology: Ask not what you can do for biology,but…

The commentaries raise questions about modularity, and about the evidence required to establish evolutionary influences on behavior. We briefly discuss evidence leading evolutionary psychologists to assume that human choices reflect evolutionary influences, and to assume some degree of modularity in human information processing. An evolutionary perspective is based on a multidisciplinary nomological network of evidence, and results of particular experiments are only one part of that network. The precise nature of, and number of, information processing systems, is an empirical question. Consumer psychologists need not retrain as biologists to profit from using insights and findings from evolutionary biology to generate new hypotheses, and to contribute novel insights and findings to the emerging nomological network of modern evolutionary science.     

A Reconsideration of Altruism From an Evolutionary and Psychodynamic Perspective

Altruistic behavior and motivation has traditionally been regarded as a defense mechanism defined by the vicissitudes of instinctual gratification. In this article, we suggest that there exists a substantial body of evidence from the fields of ethology, infant research, and experimental psychology to support the existence of an independently motivated altruism that is nondefensive in nature. We attempt to show how the view of altruism as a universal motivational system stems from the recent developments in evolutionary theory and contributes to our understanding of intrapsychic factors influencing human behavior in general and the process of psychotherapy in particular. It is not our goal to prove the existence of "pure altruism" that can never be derived from selfish motives. Rather, our thesis is that self-oriented and altruistic motivations are equal and essential partners in human evolution and development. It is the optimal balance of these two forces that is necessary for evolutionary advancement and for psychological health.