Our eyes are continuously bombarded by visual information - millions of colours, shapes and ever-changing motion - yet seeing never feels like work.

Researchers have discovered one reason: Our brains perform automatic visual smoothing over time. A new study has found that our visual perception of things is influenced by what we saw up to 15 seconds ago. This helps create a stable environment, despite sacrificing some accuracy.

It also means that what you see around you - that cup of coffee, the face of your co-worker, your computer screen - may be a time-averaged composite of now and the past.

"What you are seeing at the present moment is not a fresh snapshot of the world but rather an average of what you've seen in the past 10 to 15 seconds," said study author Jason Fischer, a neuroscientist at the Massachusetts Institute of Technology.

Oeditor wrote:And on a less serious level, could you play fast-moving video games? Let alone ball games. Or boxing? There must at least be some kind of selectivity, with processing power concentrating on changing features at the expense of more static backgrounds. Otherwise it would have taken me about half an hour to type this.