Selective effects of barbiturate and amphetamine on information processing and response execution

In a 3 × 2 × 2 factoral experiment, 12 subjects carried out a choice reaction task with reaction time (RT) and movement time (MT) as response measures.Independent variables were drug treatment (amphetamine, barbiturate, placebo), visual stimulus degradation and S-R compatibility. Visual stimulus degradation and S-R compatibility showed additive effect on the RT, but did not affect the MT. This confirms that stimulus encoding, response selection and response execution represent independent processing stages. The two drugs had selective effects on the RT and the MT. Barbiturate (as compared to placebo) had no effect on the MT, but it lengthened the RT, and this effect was additive with the effects of S-R compatibility but showed an interaction with the effects of stimulus degradation. Amphetamine (as compared to placebo) shortened the MT, but there was no significant main effect of amphetamine on the RT although the interaction with the effect of S— compatibility was significant. These results suggest that barbiturate affects stimulus encoding whereas amphetamine affects response-related processes..     

Return of fear: The role of inhibition

In a previous study investigating the relationship between subjective, physiological and behavioural changes during treatment of specific phobias, a marked between-session increase was found in subjective fear after high, but not after low intensity phobic stimulation although the groups showed similar fear ratings and heart rates immediately after treatment (Grey et al, 1979). It was hypothesized that the high intensity stimulation led to ‘treatment fatigue’; a state of deactivation, the recovery from which led to a return of fear.In this study high intensity in vivo stimulation was used for the treatment of phobic subjects under conditions of distributed and massed practice. No differences emerged between treatment conditions. A small group of Ss with a conspicuously high heart rate (mean level 120 bpm) when rating zero fear, showed a significant increase in fear after one week's interval, although they had shown similar improvement to the Ss during treatment. Subjects in both treatment conditions showed lower heart rate at all post-treatment assessments than pre-treatment. The high initial heart rate Ss continued to have higher heart rate than other Ss throughout the experiment, although they showed a decrease after treatment. It was only these Ss with desynchronously high heart rate, i.e. high heart rate with zero fear ratings, who suffered a return of fear, whereas high heart rate during high fear did not predict either response to treatment or return of fear. A further finding was a lack of correlation between the behavioural and physiological indices of fear, namely, between distance and heart rate at high levels of fear.     

Second-order conditioning with diffuse auditory reinforcers in the pigeon

Pigeon subjects were used in five experiments investigating second-order conditioning with visual second-order and diffuse auditory first-order stimuli. Experiment 1 used a discriminative conditioning procedure to demonstrate reliable and substantial second-order conditioning with these stimuli. In Experiments 2 and 3, extinction of the auditory first-order stimulus after second-order conditioning had little effect upon responding to the second-order stimulus, when compared to a stimulus whose reinforcer was maintained. Experiment 4 compared directly the susceptibility of second-order responding to extinction of the first-order reinforcing stimulus as a function of the modality of that reinforcer. When a visual second-order stimulus was paired with a visual reinforcer, and the response to the latter was extinguished, then second-order responding was greatly reduced relative to control levels. In contrast, when that reinforcer was an auditory stimulus, second-order responding was not affected by the current value of the first-order stimulus after conditioning. Finally, in Experiment 5 the auditory stimulus was established as a reinforcer through discriminative-operant training. Following second-order conditioning, extinction of responding to this stimulus again had little impact upon responding to the second-order stimulus with which it had been paired. These results are discussed in terms of previous work on second-order conditioning with rat and pigeon subjects.     

Further evidence on androgyny and interpersonal flexibility

The component scales from which Bem's index of psychological androgyny is derived are better thought of as measures of dominance and nurturance, rather than “masculinity” and “femininity.” When the Bem scales were administered to 202 male and female college students, along with eight scales that form an interpersonal circumplex, it was once again found that stereotyped, near-stereotyped, and androgynous classifications on the Bem index generalized to sex-role stereotype classifications on other dimensions of interpersonal behavior, as well. Moreover, the Bem index was found to be based on the best available combination of orthogonal interpersonal scales for measuring sex-role stereotypy. In this recent sample of college students, the hypothesis that Bem's index of androgyny reflects the more general construct of interpersonal flexibility was confirmed for both male and female subjects. The recognition that Bem's index of androgyny is specific to the interpersonal domain should encourage others to develop androgyny indices in other domains such as temperatment, interests, and cognitive styles.     

The role of self-attribution differences in the utilization of social comparison information

A study is reported that investigated the effects of receiving social comparison information which implied individual's behavior was inconsistent with his/her self-ascribed trait. The effects of this information on subsequent self-labeling and behavior involving a similar task were found to be mediated by the attributional style of the subject. The social comparison information caused subjects to reevaluate their relevant self-labels regardless of their attributional style. However, only self-attributors also changed their behavior on a later task as a result of exposure to the comparison information. These findings and their implications were discussed with regard to self-attribution and the maintenance of traitbehavior consistency.     

Dynamics of hostile aggression: Influence of anger,hurt instructions,and victim pain feedback

The research basically examined some of the dynamics of hostile aggression by looking at the effects of different Buss procedure instructions and levels of victim pain feedback on the aggressive behavior of angered and nonangered men. In a 2 × 2 × 2 completely crossed factorial experiment, male undergraduates were initially either angered or not by an experimental accomplice. When later given the ostensible opportunity to administer shocks to the same accomplice in a typical Buss procedure, the subjects were either told that longer and more intense shocks would probably interfere with the person's learning as well as causing him more pain (hurt instructions) or given no information about the effects of shocks on learning (standard instructions). Finally, after each shock they administered, the subjects were provided with either high or low victim pain feedback. The angered men were significantly more aggressive than their nonangered counterparts, and a significant interaction between anger and instructions indicated this was especially true for the men given hurt instructions. Significant interactions between the other independent variables and trial blocks revealed that the angered men, particularly those receiving hurt instructions and high victim pain feedback, displayed the greates increases in aggression. The results provide qualified support for the derived proposition about hostile aggression that signs and/or knowledge of victim injury and pain can stimulate more intense aggression from angry individuals.     

Auditory evoked potentials and sex-related differences in brain development

Auditory evoked potentials (AEPs) were obtained to probe tones which were delivered during the presentation of complex verbal and nonverbal auditory stimulation to 3-month-old infants. Significant sex-dependent AEP amplitude asymmetries were found. Females produced higher-amplitude responses from the left hemisphere and males produced higher-amplitude responses from the right hemisphere during both the verbal and nonverbal presentations. No significant AEP asymmetries were obtained in an independent group of infants that received only the probe tones. These findings are consistent with theories and behavioral data suggesting differences between males and females in the development of language and spatial functions.     

Tests that discriminate between dyslexic and other learning-disabled boys

Dyslexic and nondyslexic boys within a single community's learning-disabled class were given a set of tests; performance on each of these tests has been reported to be significantly impaired in other dyslexic children compared to learning-disabled and normal groups. Linear discriminant function analysis revealed that error types rather than levels of performance best separated the carefully matched learning-disabled groups. Slow naming and high percentage of “dysphasic” errors characterized dyslexic boys. Visual temporal-spatial matching and “configuration-deficient” perceptual errors characterized the adequate readers who have other learning disabilities.