Final answer:
Great apes prefer moving in the line of sight of the recipient, emphasizing the importance of visual signals in their communication.
Step-by-step explanation:
According to the experiment, great apes prefer moving in the line of sight of the recipient when communicating. This preference suggests that visual communication is significant in primate interaction. Even though apes can produce attention getters such as sounds and gestures, their preference leans more towards ensuring the recipient can see them, which could involve a range of visual signals from facial expressions to body movements.
The preference of great apes according to the experiment is moving in the line of sight of the recipient.