Figure 1
Stimulus configurations for the choices in the loss-chasing task as implemented in 8 standard 5-hole operant chambers and performed following full training (see Supplementary Information). On ‘partially reinforced’ (PR) trials (70% of the total), nose-poke responses in hole 5 produced food rewards. During ‘chasing episodes’, the light in hole 5 flashed (0.5 Hz) and holes 1 and 3 were illuminated to indicate choice-points involving nose-poke responses in hole 3 that yielded fixed time-out periods of 4 s (‘quit’ responses) or nose-poke responses in hole 1 that yielded no time-out periods or time-out periods of 8 s with probabilities of 0.5 (1st ‘chase’). Following losing chase responses, the light in hole 1 flashed (0.5 Hz) and holes 2 and 3 were illuminated to indicate further choice-points involving nose-poke responses in hole 3 (‘quit’ responses) that yielded fixed time-outs of 8 s or nose-poke responses in hole 2 that yielded no time-out at all or time-out periods of 16 s, again with the probabilities of 0.5 (2nd ‘chase’). For 12 of the 24 rats, the 1st and 2nd chase responses were allocated to holes 1 and 2, as described above. For the remaining rats, the allocations were swapped so that the 1st and 2nd chase responses were allocated to hole 2 and hole 1, respectively. At every choice-point, the expected value in terms of the ‘opportunity cost’ of quit responses (4 or 8 s) and chase response (0.5 × 8 s and 0.5 × 16 s) were equal, indicating no actual time advantage for either behavioral strategy.
