A concurrent-operants arrangement was used to evaluate a boy's preference for a choice condition (in which he chose the reinforcement) over a no-choice condition (in which the therapist selected the reinforcement for him) when (a) these conditions produced equal rates of reinforcement and (b) lower rates of reinforcement were associated with the choice condition. The boy preferred the choice condition even when it resulted in a much less favorable rate of reinforcement than the no-choice condition (up to 4000% less).

Aggression↗

PubMedDate not supplied

Noncontingent reinforcement: effects of satiation versus choice responding.

Recent research findings suggest that the initial reductive effects of noncontingent reinforcement (NCR) schedules on destructive behavior result from the establishing effects of an antecedent stimulus (i.e., the availability of "free" reinforcement) rather than extinction. A number of authors have suggested that these antecedent effects result primarily from reinforcer satiation, but an alternative hypothesis is that the individual attempts to access contingent reinforcement primarily when noncontingent reinforcement is unavailable, but chooses not to access contingent reinforcement when noncontingent reinforcement is available. If the satiation hypothesis is more accurate, then the reductive effects of NCR should increase over the course of a session, especially for denser schedules of NCR, and should occur during both NCR delivery and the NCR inter-reinforcement interval (NCR IRI). If the choice hypothesis is more accurate, then the reductive effects of NCR should be relatively constant over the course of a session for both denser and leaner schedules of NCR and should occur almost exclusively during the NCR interval (rather than the NCR IRI). To evaluate these hypotheses, we examined within-session trends of destructive behavior with denser and leaner schedules of NCR (without extinction), and also measured responding in the NCR interval separate from responding in the NCR IRI. Reductions in destructive behavior were mostly due to the participants choosing not to access contingent reinforcement when NCR was being delivered and only minimally due to reinforcer satiation.

Adolescent↗

PubMedDate not supplied

The chemistry of paratid and submaxillary saliva in heavy calculus formers and non-formers.

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ABO Blood-Group System↗

PubMedDate not supplied

A simplified alternative to the AOAC official method for cholesterol in multicomponent foods.

An AOAC official method for quantitating cholesterol in multicomponent foods, which was first published in the 13th edition of the Official Methods of Analysis, is rarely used. The method includes so many operations and manipulations--all described in excruciating detail--that most laboratories shun it altogether. Intent on finding an alternative, laboratories have developed their own methods for specific foods. As a result, new methods have proliferated, but still no practical method has been developed for the broader categories of multicomponent foods. The aim of AOAC, which is to promote greater accuracy and uniformity of analytical results primarily through collaborative testing, has not been well served under these circumstances. A different approach guided the work reported in the present paper. This approach was directed toward updating and dramatically simplifying the existing AOAC official method. The method's chloroform-methanol-water mixed-solvent extraction is preserved; however, all the remaining steps have been streamlined, updated, or eliminated by using newer technology. Cholesterol is quantitated with highly specific capillary gas-liquid chromatography using the internal standardization technique. The lipid extract is prepared for the chromatography step by a brief saponification carried out in a culture tube. The resulting method has been validated by using Standard Reference Materials and the standard addition method. Because a simplified method is now available for quantitating cholesterol in the lipid extracts, the expectation is that more attention can be given to the development of improved and efficient extraction methods. This step remains as the central difficulty in any number of methods of analysis for lipid analytes.

Cholesterol↗