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Five pigeons were used to test the hypothesis that the source of reinforcement for observing behavior is the information that it provides concerning the schedule of primary reinforcement. On a variable‐interval schedule, pecking the left‐hand key produced a 30‐sec display of such information. During this 30‐sec period, when pecking the right‐hand key was reinforced on a random‐interval schedule, both keys were green; when no reinforcement was scheduled (extinction) both keys were red. Later, this baseline procedure, in which both red and green were available, was replaced for blocks of sessions by procedures in which either (a) the red was eliminated and only the green could be produced; or (b) the green was eliminated and only the red could be produced. The results were that green maintained rates of pecking on the left key that were as high or higher than when both colors were available and that red maintained no responding. It was concluded that the reinforcing value of a stimulus depends on the positive or negative direction of its correlation with primary reinforcement, rather than upon the amount of information that it conveys.

Pigeons were exposed to alternative pairs of variable‐interval schedules correlated with red and green lights on one key (the food key). In one experimental chamber, responses on a white key (the changeover key) changed the color of the food key and initiated a 2‐sec changeover delay. Pigeons in a second chamber obtained food by pecking on a colored key whenever the pigeons in the first (concurrent) chamber had obtained food for a peck on that key color. There was no changeover key in the second (multiple) chamber: changeover responses in the first chamber alternated the schedules and colors in both chambers. The pigeons in both chambers emitted the same proportion of responses on each of the variable‐interval schedules, and mastered discrimination reversals at the same rate. The pigeons differed only in their absolute response rates, which were greater under the concurrent schedules. In a second experiment, changes in key color occurred automatically, with different proportions of time allocated to the two variable‐interval schedules. Matching of relative response frequency to relative reinforcement frequency was affected by the relative amounts of time in each component, by rate of changeovers, and by manipulations of the variable‐interval scheduling.

Both a small course section and a large course section were taught with methods that involved breaking material down into weekly units that had to be mastered by students as indicated by weekly tests. Attendance at lectures was voluntary and students were not tested on lecture material. In a system in which a student could receive only an A or an F for a course grade, less than 2% of the students receiving credit failed to master all material and received Fs. Students in the large course performed better on weekly tests and received fewer Fs than their counterparts in the small course, even though they rated their experience less favorably. Within the large course, the methods of tutorial interview, group discussion, and written assignment were compared in terms of their effectiveness in preparing students for weekly tests. Tutorials and written assignments were superior to group discussions in this regard. Students rated the effectiveness and enjoyability of these three methods in the reverse order from their actual effectiveness for test preparation. Some consequences of lack of congruity between attitude measures and performance measures were discussed.

Correct matches on a matching‐to‐sample procedure were reinforced under fixed‐interval, chained fixed‐interval, and fixed‐interval schedules with exteroceptive stimulus changes correlated with time since the last reinforcer (an added clock). For all four pigeons, accuracy changed within the fixed‐interval and fixed‐interval schedules with added clock, decreasing from the beginning of the interval to some point in the middle. The performance then became increasingly more accurate until the end of the interval. Under the chained schedules, accuracy also changed within the components. During the initial component, accuracy decreased from the beginning of the fixed interval to some point in the middle or at the end. During the middle component, the performance usually remained at an intermediate level of accuracy. During the terminal component, the initially inaccurate performance became increasingly more accurate throughout the interval. Systematic relationships between response rate and per cent error showed that all four pigeons performed most accurately at high rates. The accuracy of the performance at low rates was also quite high. These relationships held for all three types of schedules through an eight‐fold variation in scheduled interreinforcement time.

The reliability of the boys reporting their own behavior and the behavior of their peers was measured in two experiments at Achievement Place, a community based, family style, behavior modification program for delinquents based on a token (point) economy. The results of these experiments indicated that; (a) the boys were not “naturally” reliable observers, (b) the reliability of peer‐reporting could be improved by providing training on the behavioral definitions and by making points contingent on agreement between each boy's peer‐report and an independent adult observers' report, (c) the reliability of self‐reporting could be improved by making points contingent on agreement between the self‐report and the trained peer's report, and (d) giving self‐reports and peer‐reports did not produce a systematic effect on the boys' room‐cleaning behavior as measured by an independent observer.

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Two experiments examined mouse killing as a reinforcer of key pressing by rats that killed mice. In Experiment I, mouse‐killing rats performed the key‐pressing response when each press was reinforced with presentation of a mouse. Offered a choice between a key that yielded presentation of mice and one that did not, the rats preferred the key that yielded mice. When the contingency was reversed, the rats preferred the other key and continued to kill mice. In Experiment II, mouse‐killing rats that did not kill rat pups performed a key‐pressing response reinforced with presentation of mice on a variable‐interval schedule. In tests for responding reinforced on that schedule with presentation of normal mice, anesthetized mice, dead mice, or rat pups, these rats that killed mice but not rat pups exhibited a decline in response rate when rat pups were the reinforcer. Altering the condition of the mice did not significantly affect performance.