Habits may help animals survive

Habits are often seen as automatic and inflexible behaviours. But a new study, published in Evolution Letters, suggests that habits may have evolved as a way for animals to handle several tasks at once. By shifting to habitual behaviours for routine tasks, animals can free up attention to detect predators and other threats in the environment.

When animals search for food, they first need to explore where food can be found. But once they have learned where food is usually available, it may become costly to keep looking for new opportunities. A new study, published in Evolution Letters, suggests that it can then be beneficial to let the behaviour become a habit.

“We often think of habits as inflexible. Our results show that the ability to form and break habits is actually a powerful form of behavioural flexibility,” says Olof Leimar at Stockholm University, lead author of the study.

The researchers used computer simulations to investigate how animals search for food in environments that change over time. In the simulations, the animals first learned which food sources worked best. Once they had chosen the same option often enough, the behaviour became a habit. When the environment changed, the habit was broken and the animals started exploring again.

“Such a balance between exploration and habit can reduce the risk of being killed by predators, without the animals getting significantly less food,” says Olof Leimar.

Habits free up attention

Habits are favoured above all when rewards are predictable and the environment remains stable for longer periods. If the environment changes often, habits become less useful. Reliable signals that conditions have changed, however, make it easier for animals to leave old habits behind and start learning again.

In this way, habits may be more than automatic behaviours. They may also help animals adapt to different environments by switching between learning and habitual behaviours.

“Knowing when to explore and when to rely on a habit may be a fundamental part of how animals adapt their behaviour,” says Olof Leimar.

More about the study

The study Evolution of behavioral flexibility and the forming and breaking of habits is published in the scientific journal Evolution Letters. DOI: 10.1093/evlett/qrag024

The study is a collaboration between Stockholm University, the University of Exeter, Humboldt-Universität zu Berlin and the University of Bristol.