[Ability of monkeys to predict the direction of a movement].

The capacity of chimpanzees and baboons for extrapolating the rectalinear direction of the movement of food was studied by means of a specially evolved method. It was found that the chimpanzees have greater extrapolation capacities than baboons both in the case of immediate and delayed decision. The factors which determine the effectiveness of extrapolation are as follows: relation between the lengths of visible and invisible sections of the trajectory, as well as the angle of trajectory deflection from the vertical line. The longer the visible trajectory section, and the smaller the deflection angle, the easier the extrapolation problem.