Table 1. Number of Trials Used in Experiment 1 for Each Type of Possible Stimulus.

Learning Sequence	First Block	Second Block
Contingent-first	8 cases of AB with Disease X	8 cases of AC with Disease X
	2 cases of AB with no disease	2 cases of AC with no disease
	2 cases of B with Disease X	8 cases of C with Disease X
	8 cases of B with no disease	2 cases of C with no disease
Noncontingent-first	8 cases of A′C′ with Disease X′	8 cases of A′B′ with Disease X′
	2 cases of A′C′ with no disease	2 cases of A′B′ with no disease
	8 cases of C′ with Disease X′	2 cases of B′ with Disease X′
	2 cases of C′ with no disease	8 cases of B′ with no disease

Note—The target symptom in each condition (A and A′) is marked in bold. The notations for cues and diseases for the two learning sequences are slightly different (with an additional prime mark in the noncontingent-first sequence) to indicate that different symptoms and disorders were used, while keeping the letters of the alphabet the same to indicate the equivalence in the two blocks.