Chicks show left-to-right number bias
Like many humans, newly hatched birds favor small quantities on the left
LITTLE TO THE LEFT Young chicks seem to have their own kind of mental number line with smaller quantities toward the left.
R. Rugani
Chicken Little knows small — and like many humans may have a left-to-right bias for a mental number line of small to big quantities.
In a new kind of test, more chicks appeared to favor smaller quantities on the left and larger ones on the right, says experimental psychologist Rosa Rugani of the University of Padua in Italy. This left-to-right bias for magnitude showed up even when researchers tweaked the test so the same quantity, eight dots, appeared small or large depending on the context, Rugani and her colleagues report in the Jan. 30 Science.
It’s the only “convincing” evidence so far in animals for associating one direction with smaller quantities and the other with larger ones, says Peter Brugger of University Hospital Zurich. It’s a simple version of what many people do —creating a left-to-right mental
