Table 1. Detailed description of the actions in each of the 'social interaction’ condition for each order displayed, each clip within a block (two clips of 6 s) and each repetition (two repetitions) within the run.

	Social interaction
Order 1	Playing (roll over the other and touching the head)	Grooming (one is lying down, the other one is sitting and grooming the other one's body)
	Grooming (one is lying down, the other is sitting and grooming the other's head)	Eating a biscuit (sharing food between a mother and her baby)
Order 2	Playing in the forest (roll over the other and touching all body parts)	Playing in the forest (roll over the other and touching all body parts including playful biting)
	Grooming on a branch tree (one is lying down, the other one is sitting and grooming the other one's head)	Fighting and catching each other
Order 3	Grooming on a branch tree (one is lying down, the other one is sitting and grooming the other one's head)	Fighting and catching each other
	Playing (roll over the other and touching the head)	Grooming (one is lying down, the other one is sitting and grooming the other one's body)