Summary of Experiment 1 Design.

When three stimuli are listed (e.g., ABC-), 2nd-order occasion setting is hypothesized to be learned (except for ABR+ and TJR+). When two stimuli are listed (e.g., BC+), 1st-order occasion setting is hypothesized to be learned. When one stimulus is presented (e.g., C-), direct associative learning is hypothesized to be learned. All stimuli within a trial were presented serially. "+" indicates reinforcement; "-" indicates no reinforcement; "OS2" indicates 2nd-order occasion setting; "OS1" indicates 1st-order occasion setting; "Direct" indicates direct associative learning. Notably, the "ABC" family was trained in 2nd-order occasion setting before Transfer Test 1 and 2; the "TJK" family was only trained in 1st-order occasion setting before Transfer Test 1 but was trained in 2nd-order occasion setting before Transfer Test 2. This allowed the examination of whether "A" was indeed a 2nd-order occasion setter by testing "A" with "JK" before and after "JK" was trained with 2nd-order occasion setter "T." We predicted "A" would affect "JK" more strongly after "JK" was trained with "T" than before that training.