Table 3.

Baseline successive matching contingencies (first three columns) and nonreinforced probe-test trials (last column) in Experiment 2 for the former DODD pigeons from Experiment 1.

Form Oddity Group
Hue–form Arbitrary	Form Oddity	Hue Identity	Probe-test Trials
R → T - FI 5 s +	T → T - EXT	R → R - FI 5 s +	T → R
R → H - EXT	T → H - FI 5 s +	R → G - EXT	H → R (√)
G → T - EXT	H → T - FI 5 s +	G → R - EXT	T → G (√)
G → H - FI 5 s +	H → G - EXT	G → G - FI 5 s +	H → G
Hue Oddity Group
Hue–form Arbitrary	Hue Oddity	Form Identity	Probe-test Trials
R → T - FI 5 s +	R → R - EXT	T → T - FI 5 s +	T → R
R → H - EXT	R → G - FI 5 s +	T → H - EXT	H → R (√)
G → T - EXT	G → R - FI 5 s +	H → T - EXT	T → G (√)
G → H - FI 5 s +	G → G - EXT	H → H - FI 5 s +	H → G

Note. R = red, G = green, W = white, B = blue, T = triangle, H = horizontal, FI = fixed interval schedule, EXT = nonreinforced, + = reinforced. The first and second center-key stimuli in a trial sequence (sample and comparison, respectively) are shown to the left and to the right of the arrows, respectively.

^(√)indicates the probe trials for which higher comparison-response rates are predicted (i.e., antisymmetry).