Combinations of response-reinforcer relations in periodic and aperiodic schedules.
Reinforcer dependency controls how fast the client responds; schedule type controls the shape of those responses.
01Research in Context
What this study did
Toshikazu and colleagues built a two-part schedule. In one part every food pellet followed a peck. In the other part only some pellets followed a peck; the rest came for free.
They tested fixed-interval 60-s and variable-interval 60-s schedules. Each bird saw 0 %, 25 %, 50 %, 75 % or 100 % of food tied to the response.
The team recorded how fast and in what pattern the pigeons pecked.
What they found
More response-dependent food meant faster pecking. Birds worked hardest when every pellet depended on them.
Fixed-interval schedules gave the classic scallop: pause, then quickening to the food. Variable-interval schedules gave a steady straight-line rate.
The shape of the pattern came from the schedule, not from how much food was tied to the response.
How this fits with other research
Greene et al. (1978) saw the same pause-then-surge pattern with mild shock instead of food. The form stays the same even when the event is aversive.
Pritchard et al. (1987) found that delayed contingent food still beat free food. Toshikazu et al. extend that idea by showing rate rises smoothly as you add more contingency.
Harper (1996) showed free food can crash rates, especially when normal reinforcers are small. The new data give practitioners a dial: turn dependency up or down to tune rate without changing the schedule shape.
Why it matters
If you need more trials, raise the percentage of response-dependent reinforcement first. Keep the schedule type the same and you will keep the pattern you want. If the pattern itself is the goal—say, waiting then responding—use lean schedules only after the rate is solid.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Track how many of today’s reinforcers actually follow the target response; aim for 100 % during acquisition, then fade the percentage if you need to slow the pace.
02At a glance
03Original abstract
Key pecking of 4 pigeons was studied under a two-component multiple schedule in which food deliveries were arranged according to a fixed and a variable interfood interval. The percentage of response-dependent food in each component was varied, first in ascending (0, 10, 30, 70 and 100%) and then in descending orders, in successive conditions. The change in response rates was positively related to the percentage of response-dependent food in each schedule component. Across conditions, positively accelerated and linear patterns of responding occurred consistently in the fixed and variable components, respectively. These results suggest that the response-food dependency determines response rates in periodic and aperiodic schedules, and that the temporal distribution of food determines response patterns independently of the response-food dependency. Running rates, but not postfood pauses, also were positively related to the percentage of dependent food in each condition, in both fixed and variable components. Thus, the relation between overall response rate and the percentage of dependent food was mediated by responding that occurred after postfood pausing. The findings together extend previous studies wherein the dependency was either always present or absent, and increase the generality of the effects of variations in the response-food dependency from aperiodic to periodic schedules.
Journal of the experimental analysis of behavior, 2013 · doi:10.1002/jeab.13