A new publication in Scientific Reports shows that continuously updated predictions about future events are at the base of how we perceive the world. Predictions are essential to survival because they allow us to react faster and more appropriately to the environment. We plan what actions to perform because we can predict how effective those actions will be before we make them. Perception is also affected by brain predictions: our perceptions are the result of the combination of expectations and sensory information – we don’t perceive the world as it really is, but as we expect it to be.
We all intuitively know that we can predict the future. We know after listening to a song what will come next, when the next beat will occur, and how to clap along to that beat. Scientists from the universities of Birmingham and Sussex have used regular sequences of beats to shed light on how humans predict future timing by capitalising on the regularity of the sequence. “Our brain relies on the past history to predict what will happen next,” says Dr Di Luca. “Any regularity we encounter can inform us on what should be happening because we project what we have learned from the past into the future”.
Dr Massimiliano Di Luca and Dr Darren Rhodes have devised a model that takes into account past experience of the world to generate expectations for the future and have studied how it applies to time perception. It appears that when experiencing time, humans do not perceive it as it really is: “We are not passive watchers” says Dr Rhodes. “We use what we know about the world to inform us about when something is likely to happen. If our predictions are slightly wrong, we perceive the world somewhat in between expectation and reality. We hear, see and feel what we think we should be experiencing, not what is really happening out there.”
The authors of the research asked people to report about the timing of the last event in a regular sequence of beeps or flashes. Participants automatically and unconsciously relied on the regularity of the sequence to predict when stimuli would appear in the future. If the timing was regular, participants were able to anticipate the stimulus. If the timing of the final stimulus was made slightly off, participants reported the timing of events to be half way between when it was presented and when it was expected. These data highlight how human beings do not just merely passively perceive and react to the world. The human brain uses all information that it can capture from the senses, continuously updating beliefs and expectation to guide our thoughts and actions.
“The conclusions that that can be drawn from this research can be applied to several technological domains” says Dr Di Luca. “Knowing how the brain predicts the world can be used to teach robots how to behave and think in a way similar to humans” says Dr Rhodes, who is working at an European-funded project on the interaction between neuroscience and robotics. Dr Di Luca is currently spending his sabbatical at Oculus.
Massimiliano Di Luca & Darren Rhodes: Optimal Perceived Timing: Integrating Sensory Information with Dynamically Updated Expectations. Scientific Reports, www.nature.com/articles/srep28563, published on Jul 7, 2016