Red isn’t just a head-turner in the human world. Birds are lit by that color too, especially reddish-beaked birds called zebra finches. Male zebra finches sport beaks ranging from dark red to light orange, and females are more attracted to red-beaked males over orange ones.
The redder the beak, the hotter the male – in the (beady) eyes of the female, as redness is associated with good health (and cuter chicks!). Pun intended.
Research has proven that zebra finches classify the range of hues from red to orange into two distinct categories – much like humans – according to a phenomenon called categorical perception. Findings from Duke University in North Carolina showed that female zebra finches have a sharp perceptual boundary where red transforms to orange. At the moment, it is unclear whether the threshold between red and orange – as us humans perceive – is the same for birds. But this research champions the idea that color labels have sound biological roots and are not just arbitrary divisions sculptured by human language and culture.
Categorical color perception in zebra finches isn’t just possibly a result of how well photoreceptors in the birds’ eyes discern different wavelengths, according to Duke University researchers. It may well be in their minds. “What hits the retina is not always what we see”, said Duke postdoc associate Eleanor Caves. Signals from the retina are relayed to the brain for interpretation.
‘Categorical perception may be a cognitive shortcut that helps animals make tough decisions in the face of noisy, limited or ambiguous information’, according to Stephen Nowicki, Duke biology professor and senior author on the study.
“Categorical perception – what we show in zebra finches – is perhaps one strategy the brain has for reducing this ambiguity,” Caves said. “Categories make it less crucial that you precisely interpret a stimulus; rather, you just need to interpret the category that it’s in.”
For a summary of the experiment conducted, read the Sciencedaily article here.