Table 2. The average duration of exchanges.

The average time it took chimpanzees to exchange tokens with the experimenter in each of the four conditions across both the Baseline Phase and the Test Phase. Across all conditions, in the Baseline Phase, the average latency for a chimpanzee to return a token was 2.55 s (range: 0.91–10.65 s) while in the Test Phase the average exchange latency was 2.41 s (range: 0.92–8.94).

	Average exchange latency (range)/seconds
	Phase A	Phase B
Different	2.34 (0.91–5.84)	2.72 (1.15–8.94)
Unavailable	2.68 (0.96–6.03)	2.43 (1.14–5.41)
Low-value Same	2.69 (1.16–10.65)	2.51 (1.08–6.08)
High-value Same	2.53 (0.92–4.79)	2.00 (0.92–4.79)