Aggressive Behavior

Genetic and Neural Approaches

Edward C. Simmel, Martin E. Hahn, James K. Walters, Edward C. Simmel, Martin E. Hahn, James K. Walters

• Publisher: Routledge
• Year: 2021
• eBook ISBN: 9781000394757
• Edition: 1
• Topic: Psychology
• Subtopic: History & Theory in Psychology
• Index: Psychology

Since the heyday of research on aggression in the late 1960s, developments in several varied areas had enabled us to take a new look at this important though difficult topic. Recent findings and sophisticated new techniques in behavior genetic analysis at the time had made it possible not only to enhance our understanding of the genetic mechanisms underlying aggressive behavior, but also to provide some reasonable suggestions as to the role of aggression in evolution.

Originally published in 1983, there had been significant advances in genetic and neural research and a much more sophisticated and heuristic approach to the measurement and conceptualization of aggressive behavior had developed. The ten chapters in this volume provide a thorough overview of these new approaches and methodologies. There are also suggestions regarding the scope of future research on aggressive behavior, since much of what is presented describes the ongoing research activities of the contributors.

This book is divided into four sections: The first provides a systematic foundation for research on aggression, and a description of some of the newer strategies for research in this area; the second concerns quantitative genetic analyses, selection data from both wild and laboratory populations, and situational determinants of aggressive behavior; the third section details new and exciting findings in neurochemical and neuropharmacological effects; and the last section contains a chapter that provides a summary and synthesis of all that has come before.

II GENETICS, EVOLUTION, AND AGGRESSION

DOI: 10.4324/9781003166825-4

3 Genetic Architecture and the Evolution of Aggressive Behavior

DOI: 10.4324/9781003166825-5

J. K. Hewitt
P. L. Broadhurst
University of Birmingham England

In this chapter we consider aggressive behavior from the viewpoint of that particular approach to behavior genetics that attempts to relate the pattern of gene action and interaction manifested in intraspecific behavioral variation to the possible evolutionary pressures on the behavior and, hence, its adaptive significance. An overview of the fruitfulness of this approach for a wide range of behaviors has been provided by Broadhurst (1979), whereas the general thesis and methodology have been outlined by Broadhurst and Jinks (1974) and Jinks and Broadhurst (1974), and a summary of the approach to a particular behavior, escape—avoidance conditioning in the rat, has been presented by Hewitt, Fulker, and Broadhurst (1981). Following the format of these earlier papers, we first outline the arguments relating the consequences of different evolutionary pressures to patterns of genetic architecture, then discuss the biometrical specification and methods of analysis of the genetic variation, and lastly consider some of the relevant data available in the literature. Our detailed discussion focuses on same-sex aggression in mice because it is for this phenomenon that the kinds of data we require are available in some scope and variety. Furthermore, as a contribution to a symposium subtitled “Synthesis and New Directions,” we would be satisfied if this chapter were in part a prospective view as well as a retrospective review; for this reason we indicate some methods of analysis that we hope might find their way into the research armamentarium of students of the genetics of aggression even though there are as yet no clear examples of their application. Before embarking on this proposed program there are some remarks we would like to make about the phenotype that is the object of our analysis and that may help to set the scene for some of our later comments and conclusions.

From the outset we are not faced with a single phenotype but with a collection of phenotypes or perhaps, if we understood better the relationships among these phenotypes, what we would probably hope to describe as a system of phenotypes. Thus, even when restricting discussion to one sex of one species, Simon (1979) defines intermale aggression in mice as referring to “interactions between adult males that include the elements of threat (postural adjustments and/or facial expressions), attack (outright biting directed to the flank areas), avoidance (behaviors which minimize attack duration), escape, or some combination of these [p. 97].” Naturally, much broader definitions are often adopted, perhaps the broadest coming from sociobiologists like Wilson (1975) who, when obliged to offer a short characterization of the concept, defines aggression as, “a physical act or threat of action by one individual that reduces the freedom or genetic fitness of another [p. 577].” Wilson does, of course, offer considerable guidance to the intended interpretation of the definition when he suggests an eightfold categorization of the forms that aggression may take: territorial (that directed towards achieving dominance over subordinates); sexual; parental disciplinary (that directed towards one’s own weanlings); moralistic (aimed at enforcing reciprocation of altruism); and predatory and antipredatory aggression. As Wilson (1975) says, he is concerned that his categories of aggression should conform to adaptive categories; that is, to the different mechanisms of enhancement of individual genetic fitness. Simon’s (1979) definition was more closely concerned with specification of the precise behaviors that were to be seen as aggressive, irrespective of their ultimate adaptive functions. Our view is that the two approaches exemplified by Simon and Wilson are both necessary for a full understanding of aggressive behavior; we need clear operational definitions of the behaviors under investigation on the one hand, while we seek, on the other, to discover the significance or nonsignificance of these behaviors for individual animals seen as participants in the process of evolution. However, the very complexity of the phenotypes involved makes us wary of following Wilson too readily in asserting the adaptive function of this or that behavior, without at least some alternative form of evidence to support our assertions.

Apart from its complexity, perhaps one of the most obvious features of aggressive behavior is that it is by definition a social phenomenon (Scott, 1977); that is to say that the occasion for aggressive behavior is always the interaction of at least two individuals. The consequences of this have been explored by Fuller and Hahn (1976), who remind us that aggressive or, more generally, agonistic behavior shares this property of being social with sexual and cooperative behaviors such as parental care giving, but differs in this respect from the individual behaviors, like learning performance or activity in a standard test situation, that are more commonly the subject of behavior-genetic analysis. One reason for the relative neglect of social behaviors is surely that the additional dimensions of complexity of analysis have proved too daunting to prospective investigators. However, because those behaviors that are central to the direction of the evolutionary process, namely sexual behavior, the control of the mating system, and competitive interactions to determine the allocation of resources, are precisely those that are social in character, if we want to understand the interplay of behavior and evolution we must develop methods of analysis appropriate to social behavior. Fuller and Hahn (1976) discussed three experimental designs that might be employed, but did not pursue in detail the genetic models that could be specified or the kinds of conclusions that might be reached about the genetic architecture of social behaviors from their experimental designs. For our part, we would not claim any special insights into this problem, especially as the methods of analysis we prefer, those of biometrical genetics (Mather & Jinks, 1971), have often been developed initially within the context of plant breeding, where the problems of interaction between individuals, although not altogether absent (Breese & Hill, 1973), are not generally pa...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Other
• Front
• Original Title
• Original Copyright
• Table of Contents
• Preface
• I. Systems and Methodology
• II. Genetics, Evolution, and Aggression
• III. Neural Aspects
• IV. Summarry
• Author Index
• Subject Index