Table 2.

Line- and Hue-Sample Matching Contingencies for Each Group in Experiment 2.

Group
SID	SODD
V — FR 20 → B+	V — FR 20 → B+
H — DRL 3 s → Y+	H — DRL 3 s → Y+
B — drl/fr → B+	B — drl/fr → Y+
Y — drl/fr → Y+	Y — drl/fr → B+

Note. V  =  vertical lines, H  =  horizontal lines, B  =  blue, Y  =  yellow, DRL and drl  =  differential-reinforcement-of-low-rates-of-responding schedules, FR and fr  =  fixed-ratio schedule, (+)  =  reinforced comparison. Sample stimuli and sample-response schedules appear to the left of the arrows; reinforced comparison choices appear to the right of the arrows. Counterbalancing of the DRL 3 s and FR 20 sample-response schedules and the nonreinforced comparisons are not shown. SID  =  same comparison alternatives on all trials with identity matching contingences for red and green samples. SODD  =  same comparison alternatives on all trials with oddity contingencies for red and green samples.