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The lever pressing of four food‐ and water‐deprived rats was reinforced on concurrent variable‐interval schedules. Food reinforced one response, and water reinforced the other. Response rates in baseline were higher in the food component than in the water component. After response patterns and body weights had stabilized, the animals were given access to either food only, water only, both food and water, or neither food nor water (baseline) before daily sessions. Giving food before a session decreased per cent time in the food component, decreased overall response rates for food, and increased overall response rates for water. Giving water before a session increased per cent time in the food component, increased overall response rates for food, and decreased overall response rates for water. Giving both food and water before a session resulted in a combination of prefeeding and prewatering effects. More food and more water were consumed when both were available than when only one was available before a session.

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A reinforcement‐switching procedure was used to produce negatively reinforced key pecking in pigeons. First, key pecking on a chain schedule (fixed‐interval 10‐sec variable‐interval 60‐sec) was conditioned using grain reinforcement. Second, intermittent shock in the initial link was introduced at a low intensity and gradually increased. Third, food reinforcement in the terminal link was eliminated. With shock at 90 V occurring on the average every 3 sec, initial‐link pecking was maintained with no terminal‐link food. Three of four pigeons responded consistently at shock intensities of 90, 70, and 50 V but not at 30 V. A fourth pigeon responded at but not below 90 V. Rate of response was directly related to shock frequency. Eliminating food deprivation did not affect the negatively reinforced performance.

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Three pigeons received training on multiple variable‐interval schedules with brief alternating components, concurrently with a fixed‐interval schedule of food reinforcement on a second key. Fixed‐interval performance exhibited typical increases in rate within the interval, and was independent of multiple‐schedule responding. Responding on the multiple‐schedule key decreased as a function of proximity to reinforcement on the fixed‐interval key. The overall relative rate of responding in one component of the multiple schedule roughly matched the overall relative rate of reinforcement. Within the fixed interval, response rate during one multiple‐schedule component was a monotonic, negatively accelerated function of response rate during the other component. To a first approximation, the data were described by a power function, where the exponent depended on the relative rate of reinforcement obtained in the two components. The relative rate of responding in one component of the multiple schedule increased as a function of proximity to fixed‐interval reinforcement, and often exceeded the overall obtained relative rate of reinforcement. The form of the function relating response rates is discussed in relation to findings on rate‐dependent effects of drugs, chaining, and the relation between response rate and reinforcement rate in single‐schedule conditions.

In human subjects, discrimination learning with errors results in active responding incompatible with the reinforced response. The direction of such incompatible behavior is opposite to that of the reinforced response. Responding occurs only during the stimulus correlated with extinction. The frequency of active non‐responding is maximal shortly after the start of discrimination training (the time at which the frequency of errors decreases most rapidly) and approaches zero as discrimination training continues. The magnitude of behavioral contrast is not related systematically to the number of errors. Instead it is related directly to the frequency of active non‐responding. Active non‐responding appears to be motivated by the aversiveness of self‐produced frustration, in the sense that active non‐responding allows the subject to avoid the aversiveness of non‐reinforced responding.

Data on choice generally conform closely to an equation of the form: log(B1/B2) = a log(r1/r2) + log k, where B1 and B2 are the frequencies of responding at Alternatives 1 and 2, r1 and r2 are the obtained reinforcement from Alternatives 1 and 2, and a and k are empirical constants. When a and k equal one, this equation is equivalent to the matching relation: B1/B2 = r1/r2. Two types of deviation from matching can occur with this formulation: a and k not equal to one. In some experiments, a systematically falls short of one. This deviation is undermatching. The reasons for undermatching are obscure at present. Some evidence suggests, however, that factors favoring discrimination also favor matching. Matching (a = 1) may represent the norm in choice when discrimination is maximal. When k differs from one, its magnitude indicates the degree of bias in choice. The generalized matching law predicts that bias should take this form (adding a constant proportion of responding to the favored alternative). Data from a variety of experiments indicate that it generally does.

Group care settings for dependent people must be organized to facilitate delivery of responsive care and to prevent inadvertant neglect or deliberate abuse. Accordingly, in an infant and a toddler day‐care center, an open environment was examined as a means to increase the visibility of children to staff and of staff‐child interactions to the supervisor, and to investigate potential adverse effects of the open environment on infants' and toddlers' activities. These studies demonstrated that: (1) an open environment markedly decreased the amount of time a child could not be seen by any adult and the amount of time staff members' activities were not visible to the supervisor, and markedly reduced the effort required to supervise those who were not immediately visible; (2) an open environment did not adversely affect the sleep of either infants or toddlers; and (3) an open environment is as conducive to small group pre‐academic activities with toddlers as is a separate room. These studies convinced us that infant and toddler day care can and should be accomplished in an open environment.

The object of this study was to investigate the extent to which parents can manipulate their children's behavior in home observations. Twelve families with four‐ to six‐year old children were recruited for the research. The parents were instructed to make their child look “bad” or “deviant” on three days of a six‐day observation and to look “good” or “nondeviant” on alternate days. Results indicated that, as predicted, the rate of child deviant behavior, parental negative responding, and parental commands were all significantly higher on bad than good days. Parental responses to questionnaires provided more detailed information on how parents felt that they influenced their children in the desired directions. These results were discussed in terms of their implications for child psychopathology and the methodology of data collection in the natural environment.