Temperament

Early Developing Personality Traits

Arnold H. Buss, Robert Plomin

• Publisher: Psychology Press
• Year: 2014
• ISBN:
  9781317596127
• Edition: 1
• Topic: Psychology
• Subtopic: Personality in Psychology
• Index: Psychology

Originally published in 1984, this title looks at the development of temperament in early life. At the time of publication there were three major perspectives on temperament: paediatrics, individual differences in infants, and inherited personality traits that appear in early life. Whatever the diversity of these perspectives, they converge on personality traits that develop early in life, hence the title of this book. The authors start by looking at the main research in this field, then go on to discuss their own approach to temperament, building on their original theory from 1975.

1	Introduction

 

 

The modern history of temperament dates back only three decades to the book Personality and Temperament by Diamond (1957). Unlike the other personality texts of that era, it emphasized the constitutional origins of personality:

A crucial problem in the study of personality is to determine what are the most fundamental respects in which individuals differ from each other. All attempts to do this on the basis of observation of adult human behavior, no matter how sophisticated in either a statistical or a clinical sense, have the common failing that they are unable to distinguish between the essential foundations of individuality and its cultural elaboration, (pp. 3–4)

These essential foundations would not be restricted to humans, for “The human being, whatever else he may be, is first of all an animal, and must be understood as such” (p. 4).

Diamond went on to describe four temperaments shared by all primates and to some extent, by social mammals: fearfulness, aggressiveness, affiliativeness, and impulsiveness. He conducted no research on human behavior, however, nor did he provide any instruments to assess his temperaments. Furthermore, the 1950s were marked by a deep and pervasive environmentalism which, in this country at least, rejected the possibility of built-in tendencies and the relevance of animal behavior for the understanding of human personality. In this atmosphere, Diamond’s contribution was ignored and subsequently has rarely been mentioned.

From a different perspective, pediatric researchers of three decades ago were rebelling against the psychoanalytic approach and the environmentalism that dominated child development. Their new approach highlighted the 1960s, especially two books by Thomas, Chess, and their colleagues (1963, 1968). These investigators sought the personality traits that were both related to problems of early childhood and likely to lead to later problems or adjustment. They delineated nine temperaments in young children and assessed these temperaments by interviewing parents; the interviews were later complemented by parental questionnaires. The pediatric approach has generated an outpouring of research, and it currently dominates the area of temperament.

In parallel with the first two developments, behavioral genetics emerged as a strong trend in the 1960s. Following the lead of Diamond and earlier behavioral genetics research, we published a theory of temperament in 1975. This was a return to the personality approach to temperament, again with an emphasis on tendencies that have an evolutionary heritage. We provided measures of the temperaments, demonstrated their heritability, and suggested their course of development.

Thus the recent history of temperament is highlighted by four books: Diamond’s in the 1950s, that of Thomas, Chess and their colleagues in the 1960s, and our book and another by Thomas and Chess in the 1970s. Meanwhile, developmental psychology surged forward and became a major force in psychology. The most recent manifestation of this trend has been a focus on infancy. During the past few years, infancy researchers have been investigating individual differences in infancy and calling these personality traits temperaments. Their articles and book chapters signal the era of the 1980s.

The present era is marked by three major perspectives of temperament: pediatrics, individual differences in infants, and inherited personality traits that appear early in life. Whatever the diversity of these perspectives, they converge on personality traits that develop early in life, hence the title of this book. Tendencies that start in infancy, whether personality or other tendencies, are thought to be constitutional in origin. This broad term comprises inheritance, prenatal events, and postnatal events. Though such breadth is convenient, its vagueness poses problems for its scientific usefulness and this merits discussion. This we have done in Chapter 2, which also outlines temperament in our mammalian and primate ancestors. Presumably, temperament evolved in our forebears and was maintained during the evolution of the human species, for it is difficult to believe that most constitutional tendencies are uniquely human.

Approaches to temperament other than our own may be divided into two groups. The first consists of the pediatric approach of Thomas, Chess, and their colleagues (1963, 1968, 1977) and that of Brazelton (1973). The theory of Thomas and Chess has led to more published research than any other perspective and therefore warrants a chapter of its own, with the brief addition of Brazelton’s work at the end of Chapter 3.

The second group of approaches to temperament derives from an interest in individual differences among infants. Infants differ in many ways, but one of the most striking dimensions of variation is arousal. Even neonates vary in their sleep-wakefulness cycle, their alertness when awake, and their level of distress when they are hungry or uncomfortable. Arousal, especially emotional arousal, tends to consist of diffuse behavioral reactions which require little from the young organism in the way of learning or skill. Such diffuse reactions occur early and therefore may be regarded as constitutional in origin. Any investigator who observes infants even briefly will see that they vary considerably in their emotional reactions. It is therefore no surprise that students of individual differences among infants tend to focus on arousal. Their focus is not always the same, but there is sufficient overlap for them to be included in the chapter on arousal. Before discussing their individual contributions, however, some background on arousal is necessary. Therefore, Chapter 4 begins with a section on the concept of arousal, and the three approaches to arousal in infants are then reviewed. All of these approaches justify their use of the term temperament by referring to Allport’s definition:

Temperament refers to the characteristic phenomena of an individual’s emotional nature, including his susceptibility to emotional stimulation, his customary strength and speed of response, the quality of his prevailing mood, and all the peculiarities of fluctuation and intensity of mood, these phenomena being regarded as dependent upon constitutional make-up and therefore largely hereditary in origin (1961, p. 34).

As may be seen, this definition is sufficiently broad to support views of temperament as emotional in nature or as originating constitutionally or genetically.

The remainder of the book deals with our approach to temperament. Though we have retained much of the theory stated in our 1975 book, there are changes. Our approach to activity temperament is the same, but there are theoretical additions to the temperaments of emotionality and sociability. Chapter 5 starts with a background exposition of emotions, placing high and low arousal emotions in the context of an evolutionary scheme. Most of the chapter consists of elaborations of our previous theory of emotionality as a temperament. Sociability is discussed in Chapter 6, which begins with the motives and rewards of social interaction and then relates them to the temperament of sociability. Older children and adults seek others for slightly different reasons than do infants, which leads us to theorize about the developmental course of sociability. This temperament can easily be confused with shyness and also with extraversion; the necessary distinctions complete the chapter.

Previously, we offered five criteria of temperament, the crucial one being inheritance. We have retained inheritance as crucial and added presence early in life as an ancillary part of the definition. These issues are discussed in Chapter 7, along with our reasons for dropping impulsivity as a temperament. In this chapter, we also elaborate our ideas about how emotionality, activity, and sociability can affect the environment or modify its impact. Also included are details of new measuring instruments for the three temperaments.

A fundamental assumption in our theory is that some personality traits are inherited. It does not follow from this assumption that all or even most personality traits are inherited. Nor does it follow that the inherited tendencies are immutable, for they can certainly be modified by environmental influences. We do assume, however, that like any well-entrenched disposition, temperaments will resist modification, and no one should expect dramatic changes. Nor should anyone be surprised that heredity can account for only a portion of the variance of temperaments, which means that environment must play an important role. We raise these issues because inheritance seems to be a controversial topic, about which there may be more heat than light. Thus as a prelude to presenting data on our temperaments, we offer some essentials of behavioral genetics in Chapter 8. Here we discuss not only genes and behavior but also stability during development, gene-environmental interaction and correlation, whether some personality dispositions are more heritable than others, and also the components of the environment.

With this background, we review behavioral genetics data on our three temperaments: emotionality, activity, and sociability (Chapter 9). Though these three temperaments are not fixed and constant, they may be expected to display reasonable stability throughout childhood. Furthermore, though temperaments are susceptible to environmental influence, they may be difficult to modify. Data bearing on these two issues, continuity during development and the environment’s impact, are presented in Chapter 10.

We conclude in Chapter 11 by reviewing the salient aspects of our theory and showing how it differs from other approaches to temperament. We see temperaments as one class of personality traits, which means that issues currently being debated in the area of personality, especially breadth and stability of traits need to be discussed. Finally, we speculate about future directions for the study of temperaments.

2	Evolution and Development

Temperament researchers typically come from the disciplines of pediatrics, personality, or infancy research. Though these various perspectives have led to diverse conceptualizations of temperament, they do converge on the assumption that temperament involves early-developing personality traits. Traits are individual differences that are relatively enduring across time and situations. Personality is meant to exclude other traits such as physical and physiological characteristics and, by convention, intelligence.

The focus on infancy and childhood assumes that biological influences are more important in traits that develop early than in traits that emerge later in development. Some scientists hesitate to cope with the issue of etiology, but the clear implication is that these early-developing traits are biological in origin. Biological in this sense is loosely defined to include prenatal and perinatal events—usually referred to as constitutional—as well as physiological factors and genetics.

EVOLUTION AND EARLY DEVELOPING TRAITS

We assume that the personality traits that appear in infancy derive from millions of years of evolutionary processes. If this were true, humans would be likely to share these traits with other animals, especially those closest in the evolutionary line that led to humans. Clearly, no theory of temperament will stand or fall on whether human personality traits may also be observed in other species. The presence of such traits in other species, however, is consistent with the idea that these early-developing traits have an evolutionary heritage.

Two preliminary issues should be mentioned. Unlike comparative psychologists (e.g., Diamond, 1957), we are concerned with individual differences within a species rather than modal personality types that characterize a species. A second issue relates to evolutionary processes that can account for the appearance of similar traits across species. To argue that traits are adaptive usually connotes directional selection—that more is better. This creates a problem in that directional selection reduces genetic variability within a species. Thus, a trait tightly linked to reproductive fitness would cease to exist as an individual differences trait because no variability within the species would be tolerated by natural selection.

However, population geneticists no longer focus on directional selection exclusively and have come to recognize the importance of other types of selection which, unlike directional selection, serve to maintain genetic variability (Plomin, 1981). Such stabilizing selection seems more relevant to temperament than does directional selection. Consider sociability, for example. Though the human animal is indeed highly social, directional selection for high sociability could lead to individuals unable to act alone. It would be more adaptive to select for a range of sociability, some individuals being more sociable than others. Stabilizing selection of this sort, which conserves genetic variability within the species, is reflected in heritable traits. Obvious examples are variations in height and intelligence. If stabilizing selection has been important in our evolutionary past, traits seen in humans are likely to occur in other primates and even in other mammals.

Primates

The similarity between humans and chimpanzees in social and emotional behavior was observed decades ago by Robert Yerkes, a pioneer primatologist: “Long and intimate acquaintance with the animals enables one to recognize and distinguish expressions of shyness, timidity, fear, terror; of suspicion, distrust, resentment, antagonism, anger, rage; of interest, curiosity, excitement, elation, contentment, pleasure; of confidence, friendliness, familiarity, sympathy, affection; of disappointment, discouragement, loneliness, melancholy, and depression” (1943, p. 29). As a species, chimpanzees might share all these tendencies with humans and still not be characterized by the same set of individual differences. Yerkes suggests that they do have similar personality traits and may be different from each other as we are:

Individuality expresses itself entertainingly, and also expressively, in temperament or disposition. This is well illustrated by the following contrasts. Wendy is willful, obstinate, unpredictable, courageous, rash, determined, persistent, unaffectionate.… Bill, one of the first chimpanzees I came to know intimately, may be fairly described as her opposite. He was notably good-natured, even-tempered, buoyant, suggestible, cooperative, friendly and adaptable, dependable, cautious, and, for a male, quite timid, conservative, observant, alert, gentle, and affectionate, (p. 33)

These observations of personality traits are entirely consistent with the accounts of the Gardners (1969) and the Kelloggs (1933) with home-reared chimpanzees and of Jane Goodall (1971) who could easily recognize chimpanzees in the wild not only by appearance but also by personality traits.

More recently, chimpanzees were closely observed in a situation midway between captivity and the free-ranging situation of the wild (de Waal, 1982). After several years of watching these animals, the ethologists could easily characterize their individuality. The fastest and brightest chimpanzee in the group is Nikki: “His boundless energy and boisterous, provocative behavior has had the effect of a catalyst. Bit by bit he has disrupted the structure of the group. On cold days Nikki keeps the others warm with his constant activity and on hot days he disturbs their sleep” (p. 70). Yeroen is described as slow-moving, crafty, and calculating, as well as someone who could not be trusted. Dandy is something of a clown, but his guile and trickery may have been responsible for several attempted escapes....

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Original Title Page
• Original Copyright Page
• Table of Contents
• 1. Introduction
• 2. Evolution and Development
• 3. The Pediatric Approach
• 4. Arousal
• 5. Emotionality
• 6. Sociability
• 7. Theory and Measurement of EAS
• 8. Behavioral Genetics
• 9. Heredity and the EAS Temperaments
• 10. Continuity, Environment, and the EAS
• 11. Concluding Comments
• References
• Author Index
• Subject Index