Associations in Pavlovian conditioned inhibition

Two experiments with rat subjects used a variety of transfer tests to examine the associations learned when Pavlovian inhibition is established by an A+, AX− paradigm. Experiment 1 found in a conditioned suppression situation that inhibition conditioned to X with one exciter (A) readily transferred to another exciter (B) which had been paired with the same shock US. Transfer occurred even when the response to A had been extinguished prior to testing with B. However, X did not inhibit a general activity response produced by a B which had been subsequently paired with a food US. Experiment 2 employed a Pavlovian conditioning situation in which A and B, when separately paired with the same food US, evoked dissimilar responses. Nevertheless, an inhibitor trained in an A+, AX− paradigm successfully inhibited the different response evoked by B. However, such an X did not inhibit the behaviors acquired by A or B when they were subsequently paired with a shock US. The transfer of Pavlovian inhibition across conditioned stimuli and responses but not across unconditioned stimuli is consistent with the notion that a conditioned inhibitor acts to prevent activation of a US representation which would normally be activated by conditioned exciters.     

The effect of the blackout method on acquisition and generalization

In discrimination training with the Lyons' blackout method, pecks to the negative stimulus are prevented by darkening the chamber each time the subject approaches the negative stimulus. Stimulus generalization along a stimulus dimension was measured after training with this method. For comparison, generalization was also measured after reinforced responding to the positive stimulus without discrimination training, and after discrimination training by extinction of pecks to the negative stimulus. The blackout procedure and the extinction of pecks to the negative stimulus both produced a peak shift in the generalization gradients. The results suggest that after discrimination training in which the positive and negative stimulus are on the same continuum, the blackout method produces extinction-like effects on generalization tests.     

Innovations in Assessing ADHD: Development, Psychometric Properties, and Factor Structure of the ADHD Symptoms Rating Scale (ADHD-SRS)

This research involved the development of a behavior rating scale designed to measure ADHD and the investigation of the scale's psychometric properties and factor structure. This scale, the ADHD Symptoms Rating Scale (ADHD-SRS), was developed for the assessment of ADHD in the school-age (K–12) population. Participants were 1006 children and adolescents (in grades K–12) who were rated by their parents and/or teachers. The results indicate that the ADHD-SRS possesses strong internal consistency reliability and test–retest reliability and moderate cross-informant reliability. The data also suggest that the ADHD-SRS has strong content validity. Convergent validity of this instrument was also high, as demonstrated by correlations with three previously validated behavior rating scales. Significant age and gender differences in ADHD symptoms were found with both the parent and teacher respondent populations. Finally, the factor analysis of the ADHD-SRS suggested a two factor oblique rotation as the best fit for both the parent and the teacher data. After a visual inspection of the items which loaded on each factor, Factor 1 was named Hyperactive-Impulsive and Factor 2 was named Inattention. These two factors, along with the items which loaded on each factor, appear to be remarkably similar to the two categories listed in the DSM-IV for ADHD. Directions for future research, as well as clinical implications and limitations of the research are discussed.     

Differential effects of omission contingencies on various components of Pavlovian appetitive conditioned responding in rats

Five experiments with rat subjects investigated the effects of omission and partial reinforcement contingencies on five individual behaviors evoked by visual and auditory conditioned stimuli paired with a food unconditioned stimulus. The effects of omission depended on the behavior on which that contingency was placed: One behavior was eliminated, one was unaffected, and three were reduced relative to the performance of yoked controls. Partial reinforcement resulted in lower frequencies of three behaviors and higher frequencies of two behaviors, compared with performance under consistent reinforcement. A partial reinforcement extinction effect was noted with one behavior but not with the others. These results are related to the possible role of instrumental conditioning contingencies in generating conditioned behavior in this appetitive conditioning preparation and to the independence of individual components of a complex conditioned response.     

Differential effects of two ways of devaluing the unconditioned stimulus after Pavlovian appetitive conditioning

Three experiments with rat subjects investigated the effects of two methods of devaluing a food unconditioned stimulus (US) after pairings of an auditory conditioned stimulus (CS) with that US. Experiment 1 found no effect of postconditioning pairings of the food US with lithium chloride (LiCl) on general activity to a tone CS, even though those pairings substantially reduced food consumption. Experiments 2 and 3 compared the effects on conditioned responding of postconditioning pairings of food with LiCl and with high-speed rotation. In these experiments the general activity measure was supplemented by a detailed visual analysis of the rats' behavior. Experiment 2 found that food-rotation pairings had larger effects than food-LiCl pairings on general activity responding and on two detailed behavioral measures but that food-LiCl pairings had larger effects on food consumption and on one behavioral measure. Experiment 3 replicated the findings of Experiment 2 and found that the ability of the CS to serve as a reinforcer for second-order conditioning after US devaluation was reduced more by food-LiCl pairings.     

Differentiation of occupational perceptions among different age groups

The perception of occupations plays a key role in many vocational behaviors and in theories of vocational development. This study hypothesizes that occupational perceptions are more specific for older age groups than for younger age groups.This hypothesis was tested by using latent root analysis and minimum residual factor analysis to analyze the intercorrelations among six Vocational Preference Inventory (VPI) scales for five large and diverse samples-elementary school students, rural high school seniors, college freshmen, employed salesmen, and employed women.Both analyses supported the hypothesis. The results are discussed in relation to those of Cureton (1970) and the implication is drawn that occupational perceptions may be used to estimate a person's level of vocational development.     

Control of a continuous response dimension by a continuous stimulus dimension

Pigeons were trained to respond to stimuli from a continuous stimulus dimension (tonal frequency) with response values from a continuous response dimension. Both the number of points of correspondence and problem difficulty were varied. After training, subjects were tested with stimulus values intermediate to those trained. During these test tones, subjects emitted only those response values reinforced during training. The study suggested that if there are fast and efficient methods to obtain control of a continuous response dimension by a continuous stimulus dimension, these methods must depend on factors other than simple generalization.