Dr Jana Uher
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When biologists and psychologists talk at cross-purposes
Misunderstandings in communication happen every day—and this also happens in the sciences. A new study explored the “theories behind the theories” on “personality” and individual differences and unravelled fundamental misunderstandings between biologists and psychologists. These misunderstandings not only hamper collaborative research across disciplines; but they can also mislead the development of theories. This is an all-too-common story about how language can produce understanding and misunderstanding. A story that can also be told in the sciences.
Almost 100 years ago, pioneers of psychology, such as Wolfgang Köhler, Robert Yerkes and Donald Hebb and the physiologist and physician Ivan Pavlov reported on pronounced individual differences in the behaviour of animals, in particular, in great apes and dogs. But in those times, such reports were regarded as unscientific and were dismissed as mere anthropomorphism. The predominant idea was that only humans could develop individuality. The idea that prevailed in biology until the 1990s was the assumption that, in every animal species, there are optimal behavioural patterns and that any deviations from these optima would be random and thus unimportant. These beliefs were held despite the fact that Charles Darwin had already recognised in 1859 that individual differences are a vital precondition for evolution – but he had focussed on bodily properties rather than on behavioural ones.
But the differences in the species being studied and especially in the research methods that were being used in biology and psychology led to tremendous difficulties and a bewildering diversity of terms and concepts. Whereas a focus on individual differences and individuality was still comparably new in biology, psychologists had already been exploring these topics for more than 100 years. Francis Galton, a relative of Charles Darwin, had already developed a comprehensive body of psychological concepts and methods of analysis in the 19th century.
In everyday language, the term “personality” is used almost exclusively with regard to single individuals. A comparison of individuals with one another is commonly referred to as a consideration of “personality” differences. But in research, a different use of language was established additionally. This most likely happened because the correct labelling of the two central areas of research resulted in rather cumbersome terms. In the German-language area, for example, the entire field today is called Differential and “Personality” Psychology.
In the English-language area, by contrast, “Personality” Psychology mostly refers to both research on individual differences in populations and research on single individuals.
Animal owners are very familiar with this. A single observation does not say much about how an individual typically behaves—the individual might be scared right now or tired, hungry or ill. When choosing a new pet, it is therefore advisable to observe one’s potential new housemate on different occasions and to ask the breeder or previous owner about its habitual behaviour. Here, also, the following is very obvious: The fact that there are individual differences in the behaviours of dogs, cats, horses and other individuals towards humans and conspecifics does not say anything about what particular kind of individual we have right in front of us. Rather, it is the combination of typical behavioural tendencies that an individual shows in comparison with other individuals—his or her “personality”.
“It is curious that in the past, individual differences were dismissed as mere random variation in animal research. Today, animal researchers interpret random variation as evolutionarily meaningful”, says Jana Uher. She warns against premature conclusions. “Such dramatic changes in the interpretation of research results are always in need of explanation. They show that it is always the particular viewpoint of the researchers that determines which particular phenomena are considered worthy of an explanation and which ones are not.”
Jana Uher has also revealed fundamental differences in the ways in which researchers analyse stability. Animal researchers often report interrelations between different kinds of behaviours that show up in similar ways again at later times in the animal population under study; biologists call these behavioural syndromes. However, for identifying “personality” differences, it is individual differences and their stability over time that are essential. Certainly, when they are hungry, all individuals of a given species show more feeding behaviour and take more risks than when they are not hungry. This fact alone leads to interrelations between feeding and risk behaviours that are stable over time. But such findings do not show that in a given species there are, in fact, some individuals that take more risks than others or that feed more often than others.
But Jana Uher emphasises: “It is only research that can show which animal species show which particular kinds of stable individual differences that can be interpreted as “personality” differences, individual behavioural strategies or individual behavioural phenotypes and that may be meaningful for the evolution of the species”. There are methodologically sound studies from Australia showing that even octopuses exhibit stable individual behavioural differences. Many dog studies have shown what dog owners have already known for a long time: A dog’s individual combination of behavioural patterns does not differ from day to day and it is not merely random; rather, it characterises an individual over at least some period of time. In her studies on great apes, Jana Uher has shown how, on the one hand, stable individual behavioural differences and, on the other hand, stable but individually different combinations of behavioural patterns can be measured in “personality” profiles (see the Science Blog “No one alike – ‘personality’ differences in the great apes”).
Uher, J. (2011). Individual behavioral phenotypes: An integrative meta-theoretical framework. Why 'behavioral syndromes' are not analogues of 'personality'. Developmental Psychobiology, 53, 521–548. [Download] DOI: 10.1002/dev.20544
Last update: 16.02.2014
Keywords: personality differences, behavioral types, dispositions, responsivity, individual differences, animal personalities, personality differences, individuality, personality factors, behavioral styles, personality, behavioral profile, temperament, coping style, behavioral strategy, correlated traits, reactivity, behavioral syndromes.