PT - JOURNAL ARTICLE AU - Warrick Roseboom AU - Zafeirios Fountas AU - Kyriacos Nikiforou AU - David Bhowmik AU - Murray Shanahan AU - Anil K. Seth TI - Time without clocks: Human time perception based on perceptual classification AID - 10.1101/172387 DP - 2018 Jan 01 TA - bioRxiv PG - 172387 4099 - http://biorxiv.org/content/early/2018/03/06/172387.short 4100 - http://biorxiv.org/content/early/2018/03/06/172387.full AB - Despite being a fundamental dimension of experience, how the human brain generates the perception of time remains unknown. Here, we provide a novel explanation for how human time perception might be accomplished, based on non-temporal perceptual clas-sification processes. To demonstrate this proposal, we built an artificial neural system centred on a feed-forward image classification network, functionally similar to human visual processing. In this system, input videos of natural scenes drive changes in network activation, and accumulation of salient changes in activation are used to estimate duration. Estimates produced by this system match human reports made about the same videos, replicating key qualitative biases, including differentiating between scenes of walking around a busy city or sitting in a cafe or office. Our approach provides a working model of duration perception from stimulus to estimation and presents a new direction for examining the foundations of this central aspect of human experience.