Their finding is part of wider realization in the neuroscience community, that our brain does not simply react to what comes in through our senses. Instead, we have a predictive brain, that permanently predicts what comes next. The expected sensory input is then suppressed. We see the world from the inside out, rather than from the outside in.
Rather, in our brain’s pursuit to plan, survive, and achieve our goals, it has learned how to guess what the world is actually like based on incoming sensory data. Those predictions are always uncertain, at least to a degree, which is why the goal of predictive processing is often described as minimizing that uncertainty.