Determinants of human performance on concurrent schedules.
Human choice on concurrent VI schedules follows the person's self-stated rule more than the reinforcement ratio.
01Research in Context
What this study did
Researchers asked 30 adult volunteers to press two buttons. Each button paid points on its own variable-interval schedule. The longer a person stayed on one button, the likelier a payout became.
After the session each adult wrote down any rule they had used. The team then sorted the written rules and looked for links to each person's choice pattern.
What they found
Only 13 people showed matching. The other 17 looked almost random, favored one button too little, or locked onto one button only.
The written rules explained the difference. People who said 'I stayed about equal' did match. People who said 'I picked the better one' or 'I just liked the left' did not.
How this fits with other research
Renne et al. (1976) first showed humans can match on VI-VI schedules. Szempruch et al. (1993) now says matching happens only when the person carries a matching-type rule.
Winett et al. (1991) found that short discrimination training can flip people from matching to maximizing. The new data agree: rules, not just rates, steer the lever press.
Pierce et al. (1994) followed up by fading bad instructions until the schedule itself took over. Together the three papers show rules can block, allow, or slowly give way to contingency control.
Why it matters
When you set up a concurrent reinforcement program, ask the client what they think is happening. A simple 'Tell me why you picked that one' can reveal whether the schedule or a self-rule is driving the response. If the rule clashes with the contingency, model or rewrite the rule before you expect matching or any other schedule-typical pattern.
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02At a glance
03Original abstract
Six experiments, each with 5 human adults, were conducted to investigate the determinants of human performance on multiple concurrent variable-interval schedules. A two-key procedure was employed in which subjects' key presses produced points exchangeable for money. Variables manipulated across experiments were (a) changeover delay (Experiments 2, 4, and 6), (b) ordinal cues related to scheduled reinforcement frequencies (Experiments 3 and 4), and (c) instructions describing the ordinal relations between schedule-correlated stimuli and scheduled reinforcement frequency (Experiments 5 and 6). The performances of only 13 of the 30 subjects could be described by the generalized matching equation and were within a range of values typical of those reported in the animal literature. Eight subjects showed indifference, 9 undermatched, 7 approximated matching, 3 overmatched, and a further 3 responded exclusively to the richer component of the concurrent schedules. These differing modes of responding were closely related to the different types of performance rules reported by subjects in postexperimental questionnaires. The results are in good agreement with those from studies of human performance on single schedules, suggesting that rule-governed behavior, in interaction with contingencies, may be an important determinant of human choice.
Journal of the experimental analysis of behavior, 1993 · doi:10.1901/jeab.1993.59-29