Peeling force spectroscopy: exposing the adhesive nanomechanics of one-dimensional nanostructures.

The physics of adhesion and stiction of one-dimensional nanostructures such as nanotubes, nanowires, and biopolymers on different material substrates is of great interest for the study of biological adhesion and the development of nanoelectronics and nanocomposites. Here, we combine theoretical models and a new mode in the atomic force microscope to investigate quantitatively the physics of nanomechanical peeling of carbon nanotubes and nanocoils on different substrates. We demonstrate that when an initially straight nanotube is peeled from a surface, small perturbations can trigger sudden transitions between different geometric configurations of the nanotube with vastly different interfacial energies. This opens up the possibility of quantitative comparison and control of adhesion between nanotubes or nanowires on different substrates.

Suspiciousness, mental simulation, and norm theory.

Seven studies were conducted to replicate the work of Miller, Turnbull, and McFarland (1989), who tested predictions from norm theory (Kahneman & Miller, 1986). The first three studies with stimulus materials identical to those used by Miller et al. failed to confirm that the ease with which the event might be mentally simulated affected the degree of suspiciousness. In Studies 4, 5, and 6, the improbable events were made objectively more probable, but this did not produce significant results. In the 7th study, the objective probability and attitude toward the target were varied. Although there was a main effect for ease of mental simulation, this effect was produced by only 1 of the 3 vignettes.

The effect of noncontingent feedback on attributional style.

The relationship between experiences with noncontingency and attributional style was examined in experimental and correlational models. One hundred and twenty-six college student subjects were provided noncontingent, contingent, or no feedback as to the correctness of their responses on a concept discrimination problem. They then completed an attributional style questionnaire, a scale designed to measure life experiences with noncontingency, and a depression inventory. The experimental hypothesis was that exposure to noncontingent outcomes, both in a laboratory and historically, would result in more depressive attributions than would exposure to contingent outcomes or to no outcomes. The manipulation of feedback contingencies produced the predicted effect on attributions for positive and negative events combined into a single composite difference score. A correlation between life experiences with noncontingency and attributions was found only for the positive events measure. However, such life experiences were correlated significantly with depression.

Counselor trainees' explanations of behavior: attributions to traits, situations, and interaction.

Counselor trainees' views of generic causes of behavior were investigated. Thirty-seven counselor education graduate students were asked to assign validity ratings to seven possible explanations of what determines behavior. Participants were asked to make judgments either in reference to their own behavior or to someone else's behavior. The students assigned high validity ratings to an "interaction" explanation for behavior. Further, consistent with previous research findings that concern attributional processes, when counselor trainees explained their own behavior, they assigned relatively high ratings to external causes; when explaining others' behavior, they assigned relatively high validity ratings to internal causes.