Humans respond to environments that change at many different speeds.

A video game player, for example, reacts to on-screen events unfolding within hundreds of milliseconds or over several seconds. A boxer anticipates an opponent's moves – even when their timing differs from that of previous opponents.

In each case, the brain predicts when events occur, prepares for what comes next and flexibly adapts to the demands of the situation.

A new study, recently published in Proceedings of the National Academy of Sciences (PNAS) and authored by neuroscientists from ESI, Goethe University Frankfurt, the Max Planck Institute for Empirical Aesthetics, and New York University, explains how the human brain predicts the timing of future events.

The research shows that the brain continuously estimates how likely something is to happen within the next three seconds—and uses this estimate to prepare fast and accurate reactions.

How the brain “knows” when something will happen

Using psychophysical experiments, the researchers measured how quickly people responded to simple visual and acoustic signals, such as flashes or tones, while carefully controlling when these signals were likely to occur. From these experiments, they identified two key principles that the brain uses to predict the timing:

The brain uses the same basic probability calculation regardless of whether an event is expected in a few hundred milliseconds or in several seconds. This means the brain predicts the future in a consistent, scale-free way across different time ranges—up to at least three seconds.

At the same time, probability sharpens the sense of time: When an event is likely to happen at a certain point in time, the brain tracks time precisely. When an event is less likely, timing becomes less precise. This finding challenges a classic explanatory approach in psychology and neuroscience known as Weber's law, which suggests that timing precision should not depend on probability.

Highly flexible and efficient: The brain uses simple key principles

The brain has the fascinating ability to anticipate what will happen. The current study now explains how the brain predicts when something will happen, enabling people to react faster and more accurately.

"Our research shows that the brain relies on simple and flexible principles: it predicts the timing of future events in the same way across different situations and speeds. This helps explain why humans can adapt so easily to new environments," says Dr. Matthias Grabenhorst, commenting on the findings.

These insights can help us better understand many aspects of human behavior, including attention, decision-making, and even disorders that impair timing and prediction. The study sheds light on how the brain continuously prepares for the near future—second by second.

Click here to get to the original paper.

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