Objective and simulated stimulation: an empirical study of the effect of indirect suggestion on motor behavior

In an experimental investigation it is demonstrated that motor behavior-in contrast to the opinion forwarded in the literature-is not only elicitable by means of direct persuasion, but also to a great extend by mere indirect suggestion, (feigning of stimuli). A differential investigation of these effects provided evidence that reactions to feigned stimuli are highly person specific and relatively homogenous concerning the respective instruments whereas objective stimuli lead to reactions relatively specific for the respective instrument applied. The findings are interpreted as an analog on to placebo-effects in the area of motor behavior. Their extend may be seen as an argument for a stronger concern with subjective reaction tendencies in this field.     

Contextual stimulus control of conditional vasomotor and electrodermal reactions to angry and friendly faces

An experiment with 42 human Ss used the transswitching procedure to examine tonic stimulus control of phasic and tonic conditioned vasomotor heart rate, and electrodermal reactions. The conditional stimulus (CSs) were photos of angry and friendly human faces, and the unconditional stimulus (US) was a human scream. In one tonic context (blue light), the CSs were paired with the US, in the other context (yellow light), the CSs were presented unpaired. Following acquisition, an extinction series was run with the US omitted during both tonic contexts. Phasic vasomotor and skin conductance reactions differed in the positive and negative tonic segments (stronger in positive). The skin conductance responses also differed during extinction, but the vasomotor responses did not. Tonic differences (following onset of the tonic stimuli) in unelicited skin conductance response frequency, finger pulse volume, and heart rate were also found, although these developed more slowly than the phasic differences. The finger pulse volume tonic difference was greater in extinction than the skin conductance response frequency. There was no effect of the angry-friendly facial expressions, either directly or in interaction with the transswitching effects. The results were interpreted to mean that the transswitching phenomenon is not limited to one another autonomic effector, but is more generalized across the ANS (sympathetic branch). The absence of influence of the facial expressions indicates the relative weakness of the “preparedness” hypothesis in comparison with more influential contextual factors.     

Evaluation of visual display surfaces by real users early in the design stage

Groups of non-computer scientists were tested to evaluate the potential of an as yet non-existent interactive terminal with a screen diagonal of one meter. A simulated large image terminal provided limited realistic interactions using software developed to give close proximity to the predicted visual effect. Subjective responses from 101 subjects were elicited from a questionnaire designed to evaluate specific aspects of the “terminal” in use. From this data, two types of screen (lenticular and plain) and two types of interaction devices (touch and remote pointer) were analyzed experimentally using a two-way factorial design. Potential end-users provided positive feedback concerning future use of the Large Image Terminal. Building a realistic mock-up revealed screen contaminations which would not have been discovered until a much later stage. Although statistical analysis of screen evaluations was equivocal, the questionnaire was sufficiently penetrating to separate the positive and negative features. This methodology was invaluable in guiding the design process. Copies of the questionnaire may be obtained from the authors at the Heriot-Watt address.     

Assisting At-Risk College Students With Attributional Retraining and Effective Teaching1

Attributional retraining appears to be an effective remedial intervention for college students. However, the potential moderating effects of student and classroom characteristics have not yet been investigated systematically. In two studies, attributional retraining was provided to low- and high-risk students, followed by a videotaped lecture presented by either an ineffective or effective instructor. Attributional retraining enhanced achievement on a lecture-based achievement test only when combined with effective teaching, improving the achievement of students who had previously performed poorly (Experiment l), and of low-achieving externals (Experiment 2). The intervention provided no advantage for previously successful students and low-achieving internals. Moreover, attributional retraining induced a more internal attribution profile in students with an external locus, and increased expectations of future success in both externals and internals, but again only when students also received effective instruction. These results suggest that contextual factors related to the classroom, such as quality of instruction, and individual differences have to be considered when developing attributional retraining programs.     

Postdecisional preference for decision-relevant information as a function of the competence of its source and the degree of familiarity with this information

Three experiments are reported concerning the determinants of postdecisional preferences for decision-relevant information. Two factors were considered: the competence of the source of the information and the degree of prior familiarity with the contents of the information. The first two experiments showed that the competence of the source of decision-supporting information affected the desirability of reading both types of information, whereas the competence of the source of decision-opposing information had very little effect on the desirability of reading either type. In the third experiment, the effects of giving subjects access to prior information supporting or opposing their view on their preferences for further information were investigated under conditions in which the number of choices of this later information were either limited or unlimited. The effects of prior information on choices of decision-supporting information were identical regardless of whether the total amount of information available was limited or unlimited: Less decision-supporting information was chosen when subjects had previously been exposed to decision-supporting information than when they had not, and this difference was greater when they had not previously been exposed to decision-opposing information. However, the choices of decision-opposing information under unlimited choice conditions increased with the amount of decision-supporting information previously read, but decreased with the amount of decision-opposing information previously read. The processes that underlie the choices of information under conditions in which several types are available are discussed.