Our experience of the present is not a direct readout of the world. Signals from the eyes and other senses take time to travel and to be processed, so the brain works with slightly old information. To let us act as if events are happening right now, the brain predicts what will happen next and shows us its best guess. This creates the feeling of living in real time.
Vision shows how this works. Only a tiny central area of the eye gives sharp detail, there is a blind spot, and the eyes jump often. The brain combines these weak and noisy inputs into a stable picture by holding very brief traces of sensory data and by smoothing perception over time. This is called serial dependence, a process where what we just saw biases what we see now.
When objects move, the brain uses motion extrapolation. It uses the recent path of an object to estimate where it is likely to be in the next moment, which helps to offset processing delays. Studies in humans show neural and behavioral signs of this prediction.
Together, brief memory of the immediate past, smoothing across moments, and prediction about the near future let the brain build a useful present. The result is an illusion of now that is close to the external world and good enough for fast actions, even if it is not a perfect match to the physical instant.
eLife, How the brain stays in sync with the real world – 2023
Neuroscience research showing that the brain compensates for processing delays by predicting the position of moving objects, supporting the idea of a constructed present.
Science Advances, Illusion of visual stability through active perceptual serial dependence – 2022
Experimental evidence that active serial dependence smooths perception so that changing objects appear stable, showing the role of ultra-short-term memory in perceived present.
PLOS ONE, Crossmodal Postdiction: Conscious Perception as Retrospective Inference – 2021
A review on postdiction, where later events modify perception of earlier ones within a short time window, supporting the idea that the brain reconstructs the present from a temporal frame.
Consciousness and Cognition, Further evidence and theoretical framework for a subliminal sensory buffer store (SSBS) – 2023
Research proposing and supporting a subliminal sensory buffer store that retains unconscious traces for a very short time, improving later perception, relevant to present construction.
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