|Into the blue: Categorical vs continuous perception along a signal vs non-signal color continuum|
|Stephen Nowicki, Eleanor Caves, Patrick Green, Matthew Zipple, Sonke Johnsen, Susan Peters. Duke University, Durham, NC, United States
A common assumption in assessment signaling is that continuous variation in a signal is perceived in a continuous fashion by the signal receiver. Our previous work has shown that zebra finch females perceive variation along an orange to red continuum in a categorical fashion. Because this color continuum matches that of variation in male zebra finch beaks, a carotenoid-based signal influencing mate choice, these results suggest female assessment of beak coloration may be categorical as well. However, whether categorical perception of carotenoid-based coloration is a visual adaptation for signal perception or a more general feature of avian visual systems is unknown. To begin to address this question, we tested whether female zebra finches perceive variation along a blue to green color continuum—coloration not known to be involved in signaling in this species—in a continuous or categorical fashion. These results provide further insight into how receiver sensory systems may influence the evolution of signaling systems, and assessment signals in particular.