Table 6. Average percentage of trials with persistence during the first three sessions with opportunity for escape: Comparison of pigeons having reinforcement history with pigeons having no reinforcement history.

Session	Pigeon
	History of no escapea				No prior historyb
	367	368	369	370	W524	W520
1	0%	15%	2%	5%	68%	55%
2	1%	6%	1%	1%	93%	45%
3	0%	0%	0%	1%	60%	55%

Note. Persistence in a trial is defined as completion of that trial (excluding FR 10 trials).

^aData taken from Experiment 5.

^bData taken from Experiment 2 from the escape-optimal condition from the 2 pigeons that experienced this condition first.