Researchers at Johns Hopkins University report evidence that a brain region may control the transition from deliberate, goal-directed actions to habits. The study, published in Nature Communications, challenges the long-standing view that habit formation is always a slow, gradual process. Kishore V. Kuchibhotla, the senior author and a neuroscientist, notes that for more than 100 years scientists assumed slow strengthening through repetition, an idea that was reinforced by the design of traditional habit experiments.
Classic studies typically use strong rewards and tests at specific time points. Researchers first train animals with a reward, then allow free access to that reward so the animals become satiated. If an animal continues the task despite satiety, the behaviour is classified as habitual. Because these tests only sample behaviour at particular moments, they cannot reveal when the shift to habit actually occurs in real time, and so the change was presumed gradual.
Kuchibhotla's team developed a different method using taste preference for motivation. Mice had constant access to acidic water in their home cages so they were not overly thirsty. A sound cue delivered a preferred drink. Initially the mice behaved in a goal-directed way, responding only when they wanted the plain water. Then, at a specific moment, many mice changed strategy and began to respond to the sound reliably. The team describes the change as sudden, like a switch, and brain recordings pointed to a region that may act as that switch. The sudden shift suggests a controlling process, and some animals later returned to goal-directed behaviour after long habit periods. The National Institutes of Health awarded the team a new grant to study this possible controller. The work also received support from NIH grants and fellowships from the Kavli Neuroscience Discovery Institute at Johns Hopkins University.
Difficult words
- habit — Regular behaviour performed automatically or after repetition.habit formation, habits
- habitual — Done automatically because of past repetition.
- satiate — To satisfy hunger, thirst, or desire completely.satiated
- goal-directed — Done with a clear aim or desired result.
- reinforce — To make an idea or behaviour stronger over time.reinforced
- controller — A part that directs or regulates a process.
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Discussion questions
- What practical effects might a sudden switch to habitual behaviour have on learning new skills? Give reasons or examples.
- How does using taste preference instead of strong rewards change what researchers can observe about habit formation?
- What possible uses or risks might come from finding a brain 'switch' that controls habits?
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