Towards a visual recognition threshold: new instrument shows humans identify animals with only 1ms of visual exposure.

The human visual system is very adept at extracting categorical information from complex scenes with only the briefest of exposure. Here we show that information from visual scenes can be processed to the level of identification with formally unattainable, ultra-brief (1ms) presentations. This brief presentation time is afforded by a new instrument, the light-emitting diode (LED) tachistoscope, in which a liquid crystal display (LCD) is illuminated externally by a brief LED flash after LCD steady-state is reached, such that image onset and offset timing can be precisely controlled. Photographs of animals were presented with or without backgrounds for 1ms and 10ms. The results indicate that visual recognition of objects benefits from presenting them in isolation rather than with a background at smaller (1ms) durations. In both conditions, however, animals could be recognised at 1ms at least 83% of the time, possibly due to iconic memory and top-down, feedback mechanisms.