Table 1.

Successive Matching Training Contingencies (left three columns) and Probe Test Trials (right column) for the Pigeons in Experiment 1.

Pigeons T1, T2, T5, and T7
Hue-Form (AB)	Form-Hue (BC)	Form-Form (BB) Identity	Probe Trials (AC)
R → T - FI 5 s	T → B - FI 5 s	T → T - FI 5 s	R → B √
R → H - EXT	T → W - EXT	T → H - EXT	R → W
G → T - EXT	H → B - EXT	H → T - EXT	G → B
G → H - FI 5 s	H → W - FI 5 s	H → H - FI 5 s	G → W √

Pigeons T3, T4, T6, and T8
Hue-Form (AB)	Form-Hue (BC)	Form-Form (BB) Identity	Probe Trials (AC)
R → T - EXT	T → B - FI 5 s	T → T - FI 5 s	R → B
R → H - FI 5 s	T → W - EXT	T → H - EXT	R → W √
G → T - FI 5 s	H → B - EXT	H → T- EXT	G → B √
G → H - EXT	H → W - FI 5 s	H → H - FI 5 s	G → W

Note. R = red, G = green, T = triangle, H = horizontal, B = blue, W = white, FI = fixed interval schedule, EXT = non-reinforced, √ = probe-test trials predicted to generate higher comparison response rates. The first stimulus in the trial sequence (the sample) is shown to the left of the arrows, and the second stimulus (the comparison) is shown to the right. Note the counterbalancing of the hue-form (AB) matching contingencies.