Animal Personalities

Individual and strain differences must be taken into account when planning animal experiments

While the term "animal personality" certainly goes unchallenged among many pet owners, a scientific approach to this topic has long been controversial. However, computer simulation studies have shown that different behavioral variants can also be inherited within a population in an evolutionarily stable manner. For example, "braver" animals have an earlier reproductive success, but also a higher probability of dying earlier than their "shyer" conspecifics. Overall, the research field of "animal personality" has received a boost of interest in recent years, and numerous studies suggest that personality traits can be found in a wide variety of animal species. One generally speaks of "animal personality" when a consistency of individual behavioral differences in terms of context and time can be demonstrated. For example, an animal characterized as highly curious will always respond with great curiosity to a new environment, to new social partners, or to new food at different stages of its life.

Individual differences between genetically identical animals

In addition to the possible genetic components of "animal personality", non-genetic factors that could lead to different types of "personality" are increasingly being discussed. In this way, for example, individual differences between genetically identical animals from inbred lines could be explained. In fact, it has been shown for many years that a significant residual variability between genetically identical animals remains. Our research data show that even in what is superficially the same environment, small differences accumulate and lead to marked individual differences in behavior and neuronal plasticity. Data on the emergence of individual differences provide an important scientific basis for improving the transferability of experimental results from biomedical research to humans.

Limits to the standardizability of animal studies

The analysis of such data should also help to identify limits to the standardizability of animal studies and thus lead to better reproducibility of animal studies. In a recent study, for example, we were able to show that the reproducibility of experimental results was significantly increased by habituation to the experimental apparatus. We showed that the variability in the data did not represent random noise, but was due to stable "animal personalities". Individual differences should therefore be included in statistical models for evaluating experimental results in the future.