Does colour impact responses to images in geckos?

Abstract

Animals are exposed to different visual stimuli that influence how they perceive and interact with their environment. Visual information such as shape and colour can help animals detect, discriminate, and make appropriate behavioural decisions for mate selection, communication, camouflage, and foraging. Previous research indicates that at least some species within all major vertebrate groups prefer and can discriminate among certain colours and that colour may increase the response to a stimulus. However, since colour is often studied together with other potentially confounding factors such as movement and scent, it is still unclear what role colour plays in the perception of and attention to different stimuli. In this study, we test whether colour influences the response that an animal has to an object, and whether this influence changes depending on the type of object shown to the animal. We assessed the response of three gecko species, Correlophus ciliatus, Eublepharis macularius, and Phelsuma laticauda, to familiar and novel objects presented as colour or grayscale images. Our results indicate that colour does not change the response to objects. Specifically, we found that while all species responded more often to novel than to the familiar images, colour did not influence the response. We also found that the duration of interaction with images was significantly longer for the diurnal species, P. laticauda, than for the two nocturnal species, but this was also independent of colouration. Finally, no differences among sexes were observed within or between species. Our results show that geckos discriminate between 2D images of different content independent of colouration, suggesting that colour may not increase detectability or intensity of the response. These results are essential for uncovering which visual stimuli produce responses in animals.