Personality Research in Mammalian Farm Animals: Concepts, Measures, and Relationship to Welfare

Abstract

Measuring and understanding personality in animals is a rising scientific field. Much research has been conducted to assess distinctive individual differences in behavior in a large number of species in the past few decades, and increasing numbers of studies include farm animals. Nevertheless, the terminology and definitions used in this broad scientific field are often confusing because different concepts and methods are used to explain often synonymously applied terms, such as personality, temperament and coping style. In the present review we give a comprehensive overview of the concepts and terms currently used in animal personality research and critically reveal how they are defined and what they measure. First, we shortly introduce concepts describing human personality and how these concepts are used to explain animal personality. Second, we present which concepts, methods and measures are applied in farm animal personality research and show that the terminology used seems to be somehow species-related. Finally, we discuss some findings on the possible impact of personality on the welfare of farm animals. The assessment of personality in farm animals is of growing scientific and practical interest. Differences in theoretical frameworks and methodological approaches may also entail the diverse use of the different concepts between basic and applied research approaches. We conclude that more consistency is needed in using different theoretical concepts, terms and measures, especially in farm animal personality research. The terms coping style and temperament, which are used in different ways, should not be examined as independent concepts, but rather should be considered as different aspects of the whole personality concept. Farm animal personality should be increasingly considered for the improvement of animal housing, management, breeding and welfare.

Keywords: coping style; farm animals; personality; temperament; welfare.

Figure 1

The five personality factors in humans and how they describe the personality type of two imaginary individuals [adapted from (33)]. The equivalent personality factors described in animals are written in bold and italics. Scores are given from zero to 100 in percentages. For example, Individual A (black dashed lines and points) scored high in openness, extraversion and agreeableness, while Individual B (gray dashed lines and points) scored high on neuroticism and conscientiousness.

Figure 2

The five basic factors in animal personality research (bold lines) that can also be used to describe coping style. The dominance factor is presented in dashed lines because there are insufficient data to consider it as a fully accepted sixth factor in animal personality. The dots represent two imaginary animals with different coping styles. The animal behaving as described by the black-gray dots would represent a reactive coper, while the animal behaving as described by the black dots would be considered as a proactive individual. Intermediate individuals would express behavior described by a mixture of scores on the factors resulting in individual differences along a continuum.

Figure 3

Various behavioral tests that can be used to assess different aspects of personality. It becomes evident that coping style and temperament are sub-aspects of the concept of personality.

Figure 4

Relationship between personality and welfare. Personality directly influences behavior and physiology and therefore influences individual welfare, while as in a feedback-loop, welfare can directly influence behavior and physiology. Behavior can influence physiology and vice versa in a sort of positive feedback system. Especially in farm animals, domestication has an impact on behavior and physiology and directly influences breeding.