Figure 6.

The run was facilitated as soon as a companion chick was introduced (Experiments 1 and 2). (A) Representative running trajectories of a pair of chicks. Subject chick (purple) received 30 deliveries of food, divided into three phases. In the first phase, the subject was tested in single condition. In the second phase, a companion chick (green) was introduced into the maze. In the third phase, the subject was again tested in single condition. Each phase lasted for ca. 3 min. (B) Means (±SEM) of running distance recorded in the first and third phases of the single condition (open symbols) and in the second phase of the paired condition (filled symbol).