A02
A02
The behavioural ecology of optimism and pessimism: Do optimists and pessimists realise different individualised niches?
Helene Richter
Individuals differ in the way they judge ambiguous information. Symbolic for such situations is the often-quoted question: Is the glass half-full or half-empty? While some individuals would say it is half-full, others would describe it as half-empty, indicating the existence of optimistic and pessimistic decision-makers (i.e. “optimists” and “pessimists”). In 2004, this human psychological framework has been transferred to animal welfare science, allowing distinguishing between optimists and pessimists in non-human animals. Since under natural conditions, animals are confronted with plenty of decisions daily (e.g. choosing among feeding habitats or s electing prey items), the tendencies to see the world either optimistically or pessimistically, however, may also have an immense impact on survival and fitness. In the 1st funding period, we therefore transferred the concept of optimism and pessimism from animal welfare science to behavioural ecology. Using laboratory mice as a model species, we could show that optimism and pessimism represent moderately stable traits and that they cannot be solely explained by genotype, environment, or by genotype-by-environment interactions. Furthermore, we could demonstrate that there is no overlap between systems of optimism/pessimism and anxiety. In the 2nd funding period, we aim at expanding this idea further and investigating more deeply, whether optimists and pessimists realise different individualised niches. In particular, we will pursue the following research questions: (1) Do optimism/pessimism levels change over a lifetime? (2) Are optimism and pessimism levels linked to other individual characteristics? (3) What are the consequences of optimism and pessimism for niche choice and niche conformance? As testing mice in a touchscreen-based optimism/pessimism test turned out to be extremely time-consuming in the 1st funding period, we decided to switch both the model species and the methodological approach, and work with laboratory rats to guarantee a fast characterisation of optimists and pessimists. From a broader perspective, these changes will allow to concentrate more effectively on ecological consequences of optimism and pessimism, thereby contributing to a deep understanding of how individual traits shape niche choice and niche conformance processes.
