Figure 2

Probability of the chicks’ approaching the larger set in each of the four experiments. The dashed line indicates the chance level (y = 0.50). For each experiment, the black bar represents the median; the central dot represents the mean.

Probability of the chicks’ approaching the larger set in each of the four experiments. The dashed line indicates the chance level (y = 0.50). For each experiment, the black bar represents the median; the central dot represents the mean.