Ethanol-mediated taste aversions and state-dependency in preweanling (16-day-old) rats

Requirements for conditioning of an ethanol-mediated taste aversion in 16-day-old rat pups were examined. Experiment 1 demonstrated that preweanling rats are capable of acquiring, in two trials, an aversion to a 15% sucrose solution when followed by intragastric intubation of a 1.2 g/kg dose of 17% v/v ethanol, but not when followed by a 0.4 g/kg dose. Comparison was with control animals given sucrose followed by an equivalent volume isocaloric Half and Half. When the 0.4 g/kg dose of ethanol preceded sucrose presentation by 30 min (Experiment 2), the aversion was learned, suggesting that the effective delay between the sucrose and the critical consequences of the ethanol had been too long with the former procedure. Expression of the sucrose aversion required, however, the reinstatement of the context of intoxication--state-dependent retention. Finally, the results of Experiment 3B indicated that, in addition to the association between the sucrose and the aversive consequences of alcohol intoxication, the orosensory cues resulting from alcohol's direct elimination, via such processes as respiration and salivation, became associated with the appetitive properties of the sucrose. This was evidenced by a conditioned increase in preference for ethanol odor. Possible age-related differences in the ability to associate stimuli with alcohol's unconditioned consequences, and in state dependency are discussed.     

Teaching the Rescorla-Wagner model using STELLA-II

Although the Rescorla-Wagner model is widely taught in learning courses, most textbooks present a simplified version that does not contain all of its parameters. On the basis of Rescorla and Wagner 1972) and the Turbo PASCAL program by Lachnit, Schneider, Lipp, and Kimme! (1988), we created a simulation using STELLA-II, an icon-based program by High Performance Systems, Inc. We argue that this simulation facilitates teaching the complete Rescorla-Wagner model. Using trans-switching (Kimmel & Ray, 1978; Lachnit, 1986; Murrin & Kimmel, 1986) as an example, we demonstrate the effectiveness of the STELLA-II version of the Rescorla-Wagner model as a heuristic tool.     

Sensation seeking, augmenting-reducing, and absolute auditory threshold: a strength-of-the-nervous-system perspective

The following measures were obtained from 42 student volunteers: the General and the Disinhibition subscales of the Sensation Seeking Scale (Form IV), the Reducer-Augmenter Scale, and the Absolute Auditory Threshold. General sensation seeking correlated significantly with the Reducer-Augmenter Scale, r(40) = .59, p less than .001, and the Absolute Auditory Threshold, r(40) = .45, p less than .005. Both results proved general across sex. These findings, that high-sensation seekers tend to be reducers and to lack sensitivity to weak stimulation, were interpreted as supporting strength-of-the-nervous-system theory more than the formulation of Zuckerman and his associates.     

Factor analysis of the interpersonal trust scale with a noncollege population

This study tested the invariance of the factorial structure of Rotter's Interpersonal Trust Scale (ITS) in a noncollege population. Exploratory factor analysis of the responses of 214 volunteers yielded three factors interpreted as Exploitation, Sincerity, and Institutional Trust. This factor solution was cross-validated in a confirmation sample of 196 volunteers. Cosines between corresponding factors were high across samples and across sex. The similarity was pointed out between the present factor structure and the results of earlier studies with college students. Implications for possible refinement of the ITS were discussed.     

Coping with health threat: social influence processes in reactions to medical test results

In a laboratory experiment, undergraduate subjects tested positive for an enzyme deficiency they believed to be a risk factor for pancreatic disorders. All Ss were tested with a confederate who received a positive or negative test result. For half the Ss, the confederate expressed a minimizing appraisal of the deficiency's seriousness. Although Ss' concern about the test result was significantly reduced by what the confederate said, behavioral intentions were determined by the confederate's diagnostic status. The effect of the confederate's diagnostic status on intentions was mediated by Ss' perceptions of the deficiency's prevalence. The results support Leventhal's self-regulation theory and demonstrate that the opinions and health characteristics of comparison others have differential effects on cognitive, emotional, and behavioral aspects of coping with a health threat.     

Measurement of head movement during auditory localization

Head movement can have a significant effect on the ability to locate the direction of a sound source. A system has been designed to track the head movement in response to sound originating at different azimuth locations with respect to the head. A videotape record is made of a light approximating a point source carried on a lightweight “beanie” mounted on the listener’s head. Movement of the light is monitored by the video camera and recorded on tape, along with the sound stimulus and information concerning loudspeaker location and time. The horizontal and vertical coordinates of the light-spot image are determined in relation to the video synch pulses defining the field borders. Synch signals are available from a video monitor either in real-time or from tape replay to define each TV frame and horizontal scan line. The circuitry interfaces to a computer programmed to take the information, apply a calibration, and process the data into records of time-varying head position and velocity. Examples of both digital and graphic printouts of head movement are given. The system is capable of expansion to three-axis operation.     

Elemental representations of stimuli in associative learning

This article reviews evidence and theories concerning the nature of stimulus representations in Pavlovian conditioning. It focuses on the elemental approach developed in stimulus sampling theory (R. C. Atkinson & W. K. Estes, 1963; R. R. Bush & F. Mosteller, 1951b) and extended by I. P. L. McLaren and N. J. Mackintosh (2000, 2002) and contrasts this with models that invoke notions of configural representations that uniquely code for different patterns of stimulus inputs (e.g., J. M. Pearce, 1987, 1994; R. A. Rescorla & A. R. Wagner, 1972; A. R. Wagner & S. E. Brandon, 2001). The article then presents a new elemental model that emphasizes interactions between stimulus elements. This model is shown to explain a range of behavioral findings, including those (e.g., negative patterning and biconditional discriminations) traditionally thought to be beyond the explanatory capabilities of elemental models. Moreover, the model offers a ready explanation for recent findings reported by R. A. Rescorla (2000, 2001, 2002b) concerning the way that stimuli with different conditioning histories acquire associative strength when conditioned in compound.     

The feature-positive effect in allocations of responsibility for collaborative tasks

People commonly believe they have contributed more to collaborative tasks than others give them credit for. We distinguish between two types of contributions – additions (such as adding words to a co-authored paper) and deletions (such as removing extraneous words) – and show that individuals are especially prone to receive less credit from others than they believe they deserve when their contributions consist of taking something away rather than adding something. Participants who shortened some writing believed they improved it just as much as did participants who lengthened some, but were seen by others as having contributed less. Although one can hardly fail to notice one's own deletions, these contributions – like any contributions that, by their very nature, leave little trace of themselves – are easy for others to overlook.