PT - JOURNAL ARTICLE AU - Smithers, Samuel P. AU - Roberts, Nicholas W. AU - How, Martin J. TI - Parallel processing of polarization and intensity information in fiddler crab vision AID - 10.1126/sciadv.aax3572 DP - 2019 Aug 01 TA - Science Advances PG - eaax3572 VI - 5 IP - 8 4099 - http://advances.sciencemag.org/content/5/8/eaax3572.short 4100 - http://advances.sciencemag.org/content/5/8/eaax3572.full SO - Sci Adv2019 Aug 01; 5 AB - Many crustaceans are sensitive to the polarization of light and use this information for object-based visually guided behaviors. For these tasks, it is unknown whether polarization and intensity information are integrated into a single-contrast channel, whereby polarization directly contributes to perceived intensity, or whether they are processed separately and in parallel. Using a novel type of visual display that allowed polarization and intensity properties of visual stimuli to be adjusted independently and simultaneously, we conducted behavioral experiments with fiddler crabs to test which of these two models of visual processing occurs. We found that, for a loom detection task, fiddler crabs process polarization and intensity information independently and in parallel. The crab’s response depended on whichever contrast was the most salient. By contributing independent measures of visual contrast, polarization and intensity provide a greater range of detectable contrast information for the receiver, increasing the chance of detecting a potential threat.