Why We Don't Always Notice Our Own Movements: A Computational Perspective

Walking through a crowd. You might feel a slight push from someone passing by, but you probably won’t notice the sensation of your own steps. This is because our brains are skilled at distinguishing between sensations caused by our own actions and those generated by external factors. Scientists call this phenomenon "sensory attenuation. " They've proposed a model to understand how this happens, framing it as a type of "Bayesian causal inference. " This model suggests that when our brains infer that a sensation is caused by our own movements, the response is lessened. In other words, sensory attenuation occurs when we attribute the cause of sensory information to ourselves. This model has been tested and validated across two different sets of data. Researchers have been exploring how our brains make these distinctions. They've found that our brain's responses to sensations we produce—like the feeling of our own steps—are significantly reduced compared to responses to external sensations. This is a remarkable capability of the brain, enabling us to focus on the external world while filtering out internal noises.The model of sensory attenuation as Bayesian causal inference is an intriguing way to understand this process. Bayesian inference is a method of statistical modeling that allows us to update our beliefs based on new evidence. In this context, it means our brains continuously adjust their assessments of what's causing sensory input. When the brain determines that a sensation is self-generated, it reduces the response to that sensation. Scientists believe this process is critical for our ability to interact effectively with our environment. By accurately distinguishing between internal and external inputs, we can respond appropriately to changes and stimuli around us. This sophisticated system helps us navigate our world smoothly, often without even realizing it.