Illustration by Martin O'Neill

The number of images recorded by security cameras each day vastly exceeds human analysts' ability to examine them. "Computer vision" systems aren't much help: they're still far too primitive to tell a prowler from a postman. But researchers say the human brain can subconsciously register an anomaly in a scene -- say, a shadow where there shouldn't be one -- much faster than a person can visually and verbally identify it. If computers could somehow monitor the brain and flag these "aha" moments, surveillance analysts might be able to scan many times more images per hour.

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