Tuberculosis detection by giant african pouched rats

In recent years, operant discrimination training procedures have been used to teach giant African pouched rats to detect tuberculosis (TB) in human sputum samples. This article summarizes how the rats are trained and used operationally, as well as their performance in studies published to date. Available data suggest that pouched rats, which can evaluate many samples quickly, are sufficiently accurate in detecting TB to merit further investigation as a diagnostic tool.     

Death sentences: a content analysis of children's death literature

A multidimensional concept of death must include biological, sociocultural, and emotional components. Children glean information about death in many ways, one of which is through books. In this study, the authors compared the 3 dimensions of death-related information (irreversibility, inevitability, nonfunctionality) in 24 young children's picture books and 16 older children's storybooks. In these death-themed children's books, the primary focus was on emotional aspects of death and grieving. Biological facts were more likely to appear in picture books than in storybooks. The authors offer speculation on the impact of children's books for use with bereaved children.     

Acquisition of lever-press responding in rats with delayed reinforcement: A comparison of three procedures

The present study examined the acquisition of lever pressing in rats under three procedures in which food delivery was delayed by 4, 8, and 16 seconds relative to the response. Under the nonresetting delay procedure, food followed the response selected for reinforcement after a specified interval elapsed; responses during this interval had no programmed effect. Under the resetting procedure, the response selected for reinforcement initiated an interval to food delivery that was reset by each subsequent response. Under the stacked delay procedure, every response programmed delivery of food t seconds after its occurrence. Two control groups were studied, one that received food immediately after each lever press and another that never received food. With the exception of the group that did not receive food, responding was established with every procedure at every delay value without autoshaping or shaping. Although responding was established under the resetting delay procedure, response rates were generally not as high as under the other two procedures. These findings support the results of other recent investigations in demonstrating that a response not previously reinforced can be brought to strength by delayed reinforcement in the absence of explicit training.     

Effects of D-amphetamine on response acquisition with immediate and delayed reinforcement.

The present study examined in 8-hour sessions the effects of d-amphetamine (1.0, 5.6, and 10 mg/kg) on the acquisition of lever-press responding in rats that were exposed to procedures in which water delivery was delayed by 0, 8, or 16 seconds relative to the response that produced it. Both nonresetting- and resetting-delay conditions were studied. Although neither shaping nor autoshaping occurred, substantial levels of operative-lever responding developed under all conditions in which responses produced water. The lowest dose (1.0 mg/kg) of d-amphetamine either had no effect on or increased operative-lever pressing, whereas higher doses typically produced an initial reduction in lever pressing. Nonetheless, overall rates of operative-lever pressing at these doses were as high as, or higher than, those observed with vehicle. Thus, response acquisition was observed under all reinforcement procedures at all drug doses. In the absence of the drug, most responding occurred on the operative lever when reinforcement was immediate. Such differential responding also developed under both nonresetting- and resetting-delay procedures when the delay was 8 seconds, but not when it was 16 seconds. d-Amphetamine did not affect the development of differential responding under any procedure. Thus, consistent with d-amphetamine's effects under repeated acquisition procedures, the drug had no detrimental effect on learning until doses that produced general behavioral disruption were administered.     

The effects of behavioral history on response acquisition with immediate and delayed reinforcement

Effects of prior exposure to the experimental chamber with levers present or absent and variable-time (VT) 60-s water deliveries arranged during one, five, or no 1-hr sessions were examined in rats during a 6-hr response-acquisition session in which presses on one lever produced water delivery immediately or after a 15-s resetting delay, and presses on the other lever canceled scheduled water deliveries. Response acquisition was (a) slower to occur when water deliveries were delayed, (b) most consistent in groups that had received five VT sessions, and (c) impaired by the presence of levers only when there had been five VT sessions and water deliveries were delayed during the acquisition session.     

Self- and cross-citations in the Journal of Applied Behavior Analysis and the Journal of the Experimental Analysis of Behavior: 1993-2003

Self- and cross-citations in JABA and JEAB from 1993 through 2003 were examined. Yearly mean levels of self-citation for JABA and JEAB were 34.9% and 33.2%, respectively. Overall, 7.8% of JABA citations were JEAB articles, and 0.6% of JEAB citations were JABA articles. The former value, but not the latter, is substantially higher than the cross-citation level reported for earlier years. The two JEAB articles most often cited in JABA were published over 20 years ago and are concerned with establishing operations and the matching law.     

Rates of personality disorders in substance abusers: a comparison between DSM-III-R and DSM-IV

The publication of the DSM-IV represents the first revision in 7 years to the DSM-III-R diagnostic criteria. The purpose of the current study is to evaluate the impact of changes to the Axis II criteria on diagnostic rates in a substance abusing population. We interviewed 370 patients entering treatment using a modified version of the SCID-II, which allowed for the diagnosis of both DSM-III-R and DSM-IV Axis II diagnoses. Prevalence rates for each Axis II disorder are given, as well as kappa statistics showing diagnostic agreement between the two systems. The results of this study indicate good rates of diagnostic agreement between the two systems with a few notable exceptions. Poor rates of diagnostic agreement were obtained for the histrionic and dependent diagnostic categories. No single diagnostic change appears to be responsible for the prevalence rate differences between the two systems.     

Response acquisition with delayed reinforcement: a comparison of two-lever procedures.

Groups of 8 experimentally naive rats were exposed during 8-hr sessions to resetting delay procedures in which responses on one lever (the reinforcement lever) produced water after a delay of 8, 16, 32, or 64 s. For rats in one condition, responses on a second (no-consequences) lever had no programmed consequences. For rats in another condition, responses on a second (cancellation) lever during a delay initiated by a response on the reinforcement lever prevented delivery of the scheduled reinforcer; responses on the cancellation lever at other times had no programmed consequences. Under both conditions and at all delays, most subjects emitted more responses on the reinforcement lever than did control rats that never received water emitted on either lever. At 8-s delays, both conditions engendered substantially more responding on the reinforcement lever than on the other lever, and performance closely resembled that of immediate-reinforcement controls. At delays of 16 and 32 s, however, there was clear differential responding on the two levers under the cancellation condition but not under the other condition. When the delay was 64 s, differential responding on the two levers did not occur consistently under either condition. These findings provide strong evidence that the behavior of rats is sensitive to consequences delayed by 8, 16, and 32 s, but only equivocal evidence of such sensitivity to consequences delayed 64 s. They also indicate that acquisition depends, in part, on the measure of performance used to index it.