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Spaced feeding of individual food pellets to food‐deprived rats induced excessive drinking after pellet delivery if water was continuously available. When access to water was restricted to a portion of the inter‐pellet interval, and competition from food‐reinforced bar pressing was removed, excessive drinking occurred whenever drinking was possible. This finding extends the generality of accounts of excessive behavior that implicate induction by apparently unrelated scheduling characteristics of the environment.

Although language remediation programs have generally been conducted with the use of special materials in structured group settings, traditional preschool practice emphasizes “incidental teaching” incorporated into children's free play. To determine if incidental teaching practices could be effective in improving children's speech, this study investigated the spontaneous speech of 12 disadvantaged children during free‐play periods over eight months of a preschool program. Whenever the children selected a preschool play material, they were prompted and required to ask for it, first by name (noun), then by name plus a word that described the material (adjective‐noun combination), then by use of a color adjective‐noun combination, and finally by requesting the material and describing how they were going to use it (compound sentence). As each requirement was made, the children's general use of that aspect of language markedly increased, but little change was noted in the amount or nature of the children's interactions with teachers or their use of a set of materials to which they had free access. This study demonstrates that preschool free‐play periods can be powerful “incidental teaching” periods by capitalizing on moments when children seek new play materials.

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Five pigeons pecked for food reinforcers on a concurrent variable‐interval one‐minute, variable‐interval four‐minute schedule. Each bird's body weight was varied from 80% of its free‐feeding weight to 95% and then by 5% steps to 110% or until weight gains ceased. The coefficient of variation, but not the standard deviation, of the daily rate of responding on each of the component schedules increased with increases in body weight.

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The fixed effects ANOVA procedure utilized by Gentile, Roden, and Klein (1972) for single subjects is found inappropriate. Hartmann's proposal of a one‐way fixed‐effect ANOVA model is also considered. Time series analysis that takes serial correlation effects into account is recommended.

A key was illuminated on the average of every 30 sec for a duration of 6 sec and this was followed by food presentations. When key pecks in the presence of the light produced immediate access to grain (autoshaping procedure) pigeons were likely to peck. When pecks terminated the keylight but prevented access to grain (automaintenance procedure) pigeons were much less likely to peck. Seven of 12 pigeons failed to develop responding during the automaintenance procedure. Four of the five pigeons that responded during the automaintenance procedure were exposed to a procedure in which responses could not immediately terminate the light. Three of the four ceased to respond during optimal automaintenance conditions, suggesting that the response‐dependent offset of the keylight had been reinforcing their pecking. Responding during the automaintenance procedure was eliminated for a fifth pigeon by eliminating the contiguity of light‐offset and food‐onset on those trials in which the pigeon did not peck. These results suggest that: (1) automaintenance (unlike autoshaping) is not an effective procedure for reliably generating responding; (2) responding that does occur during the automaintenance procedure is reinforced by the response‐dependent offset of the keylight.

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Average response rate, post‐reinforcement pause, elapsed time to the fourth response, average quarter‐life, and running rate were examined to see how they reflected changes in fixed‐interval performance. Rats were exposed to a mixed schedule of water presentation comprising fixed‐interval schedules of two durations. Changes in responding were produced by varying the duration of the shorter component. The five measures were derived only from the longer schedule component. Post‐reinforcement pause, elapsed time to the fourth response in the interval, and quarter‐life all showed high, positive inter‐correlations (0.78 < r < 0.99). Running rate and post‐reinforcement pause were not as highly correlated. Quarter‐life reliably reflected changes in fixed‐interval performance but changes in the quarter‐life value did not necessarily result from similar changes in fixed‐interval response pattern. The two measures that adequately described changes in response patterning were post‐reinforcement pause and running rate. These two measures also had the advantage of being simple both computationally and in terms of the instrumentation involved in their recording.