Koichi Ono

Free-choice preference under uncertainty

Preferences in pigeons for free choice over forced choice under uncertain contingencies were compared with the one under certain contingencies in multiple concurrent-chain schedules of reinforcement. The uncertain condition examined the preference for two alternatives over one alternative when reinforcement probability at the end of the terminal link equalled 0.5, and with all keys in each terminal link lit green (two mixed fixed-interval extinction keys versus one mixed fixed-interval extinction key). Key and schedule arrangement in the certain condition was the same except that a peck on any terminal-link key after the FI interval always produced food. When naive pigeons were first exposed to uncertain contingencies, preference for two lit keys over one lit key was observed, and the preference was confirmed by sequential reversals of the terminal-link contingencies. However, no consistent preference was observed when uncertain condition followed the certain condition. Under certain contingencies, unlike the earlier experiments, very small and inconsistent preferences for free choice were demonstrated. A possible reason for the different preferences in the uncertain conditions was that pigeons may lessen their sensitivity to the circumstances with uncertainty by any history or carry-over effect of the prior contingency.

Sources of Novel Behavior: Stimulus Control Arranged for Different Response Dimensions

Properties of pigeons’ pecks on a two-by-two array of four keys were brought under the control of three stimulus dimensions. Stimulus form (circle or plus) determined key column (left or right), stimulus number (one or two) determined key row (top or bottom), and stimulus color (green or red) determined rate (fast or slow). Appropriate control of responding by all eight possible combinations of stimulus properties sometimes emerged even when performance was established with incomplete contingencies. For example, if high-rate contingencies never operated during presentations of one circle on green and low-rate contingencies never operated during presentations of two plusses on red, appropriate high and low rates nevertheless emerged in the presence of all combinations of green and red with the other stimulus properties. In tests of the emergence of combined stimulus control over different response properties, procedures that maintain reinforcement contingencies for some response dimensions while relaxing contingencies for others may have advantages over those that are conducted during extinction.

The role of terminal-link stimuli in concurrent-chain schedules : revisited using a behavioral-history procedure

A behavioral-history procedure was used to study the function of terminal-link stimuli as conditioned reinforcers in multiple concurrent-chain schedules of reinforcement. First, three pigeons were exposed to multiple concurrent-chain schedules in which the two multiple-schedule components were correlated with a blue and a white stimulus, respectively. In each component the initial links were equal independent variable-interval (VI) 15 s schedules. A fixed-interval (FI) 10 s schedule operated on the red key in one terminal link while extinction operated on the green key in the alternative terminal link. When large preferences for the red stimulus had been established, two tests were conducted. In the terminal-link test, under new initial-link stimuli--purple and brown--an FI 10 s schedule operated for both the red and green terminal-link stimuli. In the subsequent initial-link test, the blue and white initial-link stimuli were reintroduced, and, as in the terminal-link test, FI 10s operated for both the red and the green terminal-link stimuli. In the terminal-link test, the three pigeons showed no preference for the terminal links with the red stimulus, but showed clear and consistent preferences for the red stimulus when blue and white stimuli were reintroduced as initial-link stimuli in the initial-link test. This suggests that there are multiple sources of control over initial-link response allocation in concurrent-chains, including control by both terminal- and initial-link stimuli.

Response Stereotypy in Humans Maintained by Response-contingent Events

The present study examined stereotyped behaviors developed during human performances that were generated by response-dependent intermittent schedules of reinforcement. Thirty university students were assigned to either fixed-interval 30-s or fixed-ratio 30-s schedules in which points or monetary reinforcers were produced only by presses on the number keys of a 41-key computer keyboard. Behavior patterns developed by all subjects were classified into four categories: optimal, random, unique, and general stereotypes. The general stereotypes category was further subdivided into five idiosyncratic types: connection, order, shift, repeat, and restriction. Analysis of the data demonstrated the role of contiguity: Whatever behavior happened to precede reinforcers was repeated even though reinforcers did not depend on that behavior. These findings support the argument that much of idiosyncratic and stereotyped human behavior is produced and maintained by contingencies of reinforcement, rather than schedule-induced or adjunctive behavior.

Masaya Sato (1932–2010)

​MasayaMasaya Sato died in the summer of 2010. He was a pioneer of behavior analysis in Japan and the leader of the Japanese Association for Behavior Analysis (J-ABA). He also contributed to the dissemination of behavior analysis around the world. One of his major accomplishments was to help the Association for Behavior Analysis International (ABAI) to become truly international through his election as the first ABAI president from outside the United States. In fact, he was a great antecedent for behavior analysts.