Table 2.

Training stages.

Stage	Name	Goal	Water delivery	Criterion to advance
1-DS	Direct sides	Get animals to poke and collect water	After center or side poke	One session with 200 rewards
2-DC	Direct center	Trial initiation in center poke	After center poke	One session with 200 rewards
3-RS	Require side	Require response shortly after trial initiation	After trial initiation and associated side poke	One session with 200 trials
4-ID	Increase delay	Require animals to stay in center port longer	After trial initiation and associated side poke	One session with 200 trials, or 3 consecutive sessions with more than 100 trials
5-RC	Require correct	Full two-alternative choice sound discrimination	Only after correct side poke	Two consecutive sessions with 80% correct for each stimulus.
6-SB	Switch in blocks	Full flexible categorization task, switching every 300 trials	Only after correct side poke (switches for one sound)	One session with 70% correct for the reversing stimulus
7-OK	Ready	Ready for psychometric measurements	Only after correct side poke (category boundary switches)