Idealizations,essential self-adjointness,and minimal model explanation in the Aharonov–Bohm effect

Two approaches to understanding the idealizations that arise in the Aharonov–Bohm (AB) effect are presented. It is argued that a common topological approach, which takes the non-simply connected electron configuration space to be an essential element in the explanation and understanding of the effect, is flawed. An alternative approach is outlined. Consequently, it is shown that the existence and uniqueness of self-adjoint extensions of symmetric operators in quantum mechanics have important implications for philosophical issues. Also, the alleged indispensable explanatory role of said idealizations is examined via a minimal model explanatory scheme. Last, the idealizations involved in the AB effect are placed in a wider philosophical context via a short survey of part of the literature on infinite and essential idealizations.     

Generation enhances semantic processing? The role of distinctiveness in the generation effect

The goal of the present study was to investigate the locus of the memory advantage for words that are generated according to a nonsemantic rule (letter transposition) over words that are presented intact (read words). In the first two experiments, a category instance generation task was used to test the possibility that the semantic features of generated words are more readily available than those of read words. This possibility was not supported. In Experiment 3, generation effects were found to depend on the level of meaningfulness of words in recall, but not in recognition. In Experiment 4, a between-list design eliminated the generation effect found in recall, but did not affect the generation effect in recognition. Taken together, these findings suggest that generating a target according to a letter transposition rule enhances the distinctiveness of the word along a nonsemantic dimension.     

What is the role of affect in the spacing effect?

In Experiments 1 and 2, after studying a list containing connotatively neutral words that were presented once or were presented at various spacing intervals, subjects either attempted free recall or made affective judgments of the study-list targets along a pleasant/unpleasant dimension. Spacing effects occurred in recall, and massed items were judged to be more unpleasantthan once-presented and spaced words. In the third experiment, subjects studied homogeneous lists composed of either connotatively good words or connotativelybad ones. Spacing effects were absent in the recall of both types of words because massed-practice words were recalled at a high level, one that was about the same as that for spaced-practice words. Affective judgments were unrelated to presentation condition, and both good and bad massed words were judged to be positive in affect. Although the data suggest that different study conditions can lead to different affective reactions, the results are moot with regard to the relationship between affect and the magnitude of spacing effects.     

The role of emotion in bridging the intention–behaviour gap: The case of sports participation

ProblemPsychological models of sports participation frequently draw on the Theory of Planned Behaviour (TPB) in order to predict health-behaviour-related intentions. While these models commonly show high predictive power with respect to intention, they often fall short in the prediction of behaviour (the ‘intention–behaviour gap’). The present study contends that integrating emotional processes into TPB can substantially improve the model's predictive power over and above traditional cognitive predictors.MethodIn a longitudinal study structural equation modelling was employed to test a traditional model (based on TPB) and an extended model including emotion associated with the intention to exercise as a mediator variable. A community sample (N = 237) completed a questionnaire measuring the components of a traditional TPB model. Prior to each of 16 expected exercise sessions (over 8 weeks) intention to exercise and emotion associated with the intention were measured.ResultsResults confirmed a substantial increase of 17% in explained variance of exercise frequency and 20% in exercise duration for the extended model. Emotional appraisal of the intention to exercise thus appears to mediate the traditional intention–behaviour relationship, suggesting that emotionally based interventions aimed at increasing sports participation may be helpful.ConclusionIt is concluded that emotion variables should be added to traditional TPB models in order to predict health behaviour more fully.     

Beyond unusual? Examining the role of attention in the weapon focus effect

The current study examined whether the weapon focus effect could be accounted for in terms of stimulus novelty. Participants viewed a slideshow of a simulated event while attending to a secondary task. In the critical slide, the target was shown holding a threatening object (weapon condition), a novel object (unusual condition) or a neutral object (control condition). Reaction times on the secondary task were impaired in the weapon and unusual conditions. Participants in the weapon condition had poorest recognition scores for the target's appearance when confidence was also taken into account. Results suggest that while both unusual and threatening objects command attention, the significance of a weapon can lead to impaired performance on less immediately informative aspects of a scene such as target appearance. Copyright © 2006 John Wiley & Sons, Ltd.     

The role of attention in the affordance effect: can we afford to ignore it?

It has been established that the task-irrelevant orientation of an object's graspable handle produces a stimulus-response compatibility effect, resulting in faster reaction times when the location of the response corresponds to that of the object's handle. There is ongoing debate whether to attribute this affordance effect to motoric or to attentional components. In an attempt to reconcile these two viewpoints, we employed a novel experimental approach for investigating the relationship between attention and affordance. Using 3-D positional sound, auditory spatial attention was manipulated in order to explore its effects on affordance. Subjects were presented images of everyday graspable objects and had to respond bimanually (left or right) whether the object (featuring a leftward or rightward handle) was presented upright or upside-down. Prior to each affording object, sound localization cues were manipulated so as to orient auditory attention to the left, or to the right of the interaural axis (control). We obtained a peculiar pattern of results, which not only appears to provide support for an attention-shift account of affordance but does so in a cross-modal context.     

The role of visual-auditory “compellingness” in the ventriloquism effect: Implications for transitivity among the spatial senses

A magnitude estimation response procedure was used to evaluate the strength of visualauditory intersensory bias effects under conditions of spatial discrepancy. Maj or variables were the cognitive compellingness of the stimulus situation and instructions as to the unity or duality of the perceptual event. With a highly compelling stimulus situation and single-event instructions, subjects showed a very high visual bias of audition, a significant auditory bias of vision, and a sum of bias effects that indicated that their perception was fully consonant with the assumption of a single perceptual event. This finding reopens the possibility that the spatial modalities function as a transitive system, an outcome that Pick, Warren, and Hay (1969) had expected but did not obtain. Furthermore, the results support the model for intersensory interaction proposed by Welch and Warren (1980) with respect to the susceptibility of intersensory bias effects to several independent variables. Finally, a new means of assessing intersensory bias effects by the use of spatial separation threshold was demonstrated.     

Reciprocity of trust in the supervisor–subordinate relationship: The mediating role of autonomy and the sense of power

This article develops and tests a model of reciprocal trust between supervisor and subordinate. Drawing from literature on trust and control and on the approach/inhibition theory of power, the authors present a model in which supervisor trust is suggested to enhance subordinate reciprocal trust through increased work-related autonomy and a heightened sense of power. The mediator analysis using the two-level full structural model confirmed that the relationship between supervisor trust and subordinate trust was partially mediated by the suggested chain of variables. The article responds to a call for empirical studies on reciprocal trust and offers a complementary mechanism for trust building beside characteristics and relationship-based approaches.     

The word class effect in the picture–word interference paradigm

The word class effect in the picture–word interference paradigm is a highly influential finding that has provided some of the most compelling support for word class constraints on lexical selection. However, methodological concerns called for a replication of the most convincing of those effects. Experiment 1 was a direct replication of Pechmann and Zerbst (2002 Pechmann, T. and Zerbst, D. 2002. The activation of word class information during speech production. Journal of Experimental Psychology: Learning, Memory, and Cognition, 28: 233–243. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Experiment 4). Participants named pictures of objects in the context of noun and adverb distractors. Naming took place in bare noun and sentence frame contexts. A word class effect emerged in both bare noun and sentence frame naming conditions, suggesting a semantic origin of the effect. In Experiment 2, participants named objects in the context of noun and verb distractors whose word class relationship to the target and imageability were orthogonally manipulated. As before, naming took place in bare noun and sentence frame naming contexts. In both naming contexts, distractor imageability but not word class affected picture naming latencies. These findings confirm the sensitivity of the picture–word interference paradigm to distractor imageability and suggest the paradigm is not sensitive to distractor word class. The results undermine the use of the word class effect in the picture–word interference paradigm as supportive of word class constraints during lexical selection.     

The role of task rules and stimulus–response mappings in the task switching paradigm

Switch costs occur whenever participants are asked to switch between two or more task sets. In a typical task switching experiment, participants have to switch between two task sets composed of up to four different stimuli per task set. These 2 (task sets) x 4 (stimuli) contain only 8 different stimulus-response (S-R) mappings, and the question is why participants base their task performance on task sets instead of S-R mappings. The current experiments compared task performance based on task rules with performance based on single stimulus-response mappings. Participants were led to learn eight different S-R mappings with or without fore-knowledge about two underlying task sets. Without task set information no difference between shifts and repetitions occurred, whereas introducing task sets at the beginning led to significant switch costs. Most importantly, introducing task sets in the middle of the experiment also resulted in significant switch costs. Furthermore, introducing task rules at the beginning of the experiment lead to slower RTs when simple stimuli (Experiment 1) had to be processed. This detrimental effect disappeared with more complex stimuli (Experiment 2). Results will be discussed with respect to cognitive control.     

The role of input–output modality compatibility in task switching

Input–output (I–O) modality compatibility refers to the similarity of stimulus modality and modality of response-related sensory consequences. A previous study found higher switch costs in task switching in I–O modality incompatible tasks (auditory-manual and visual-vocal) than in I–O modality compatible tasks (auditory-vocal and visual-manual). However, these tasks had spatially compatible S–R mappings, which implied dimensional overlap (DO). DO may have led to automatic activation of the corresponding compatible responses in the incorrect response modality, thus increasing interference effects. The present study was aimed to examine the influence of DO on I–O modality compatibility effects. In two experiments, we found that I–O modality compatibility affects task switching even in tasks without DO, which even tended to result in further increased modality influences. This finding suggests that I–O modality mappings affect response selection by affecting between-task cross-talk not on the level of specific response codes but on the level of modality-specific processing pathways.     

On the role of lyrics in the music–exercise performance relationship

ObjectivesTo examine the role of lyrics on a range of psychological, psychophysical, and physiological variables during submaximal cycling ergometry.DesignWithin-subject counterbalanced design.MethodTwenty-five participants performed three 6-min cycling trials at a power output corresponding to 75% of their maximum heart rate under conditions of music with lyrics, same music without lyrics, and a no-music control. Cycling cadence, heart rate, and perceived exertion were recorded at 2-min intervals during each trial. Positive and negative affect was assessed before and after each trial.ResultsParticipants cycled at a higher cadence towards the end of the cycling trials under music with lyrics. Main effects were found for perceived exertion and heart rate, both of which increased from min 2 through to min 6, and for affect: positive affect increased and negative affect decreased from pre- to post-trials.ConclusionsParticipants pedalled faster in both music conditions (with and without lyrics) while perceived exertion and heart rate did not differ. The inclusion of lyrics influenced cycling cadence only at min 6 and had no effect on the remaining dependent variables throughout the duration of the cycling trials. The impact of lyrical content in the music–exercise performance relationship warrants further attention in order for us to better understand its role.     

The role of eye movements in the Müller-Lyer illusion

The size of the illusion was found to be unaffected by reducing the exposure of the figures tachistoscopically, or by reducing the size of the figures. The illusion therefore does not seem to be due to eye movements or a tendency to make eye movements.     

Who has the street-smarts? The role of emotion in co-creating the city

Elizabeth Grosz argues that bodies and cities co-create one another; bodies build cities but cities in turn shape bodies, physically and socially. Recent findings in neurobiological research confirm that environmental factors can change the way DNA is folded, affecting such things as mood regulation and impulse control. In turn, emotional factors affect our capacity to shape our environment. But is each citizen afforded with the same opportunities and capacity to shape the city and the same susceptibility to being shaped by it? This paper suggests, following Michel de Certeau, that although even the apparently powerless can change cities, those who are emotionally robust are more effective. The paper presents a collaborative creative installation in Melbourne between one of the authors and a group of homeless and socially isolated women, and contrasts it with the work of graffiti artists to demonstrate the effect that emotion has on the capacity of the marginalised to shape the urban fabric. The second author provides evidence from neurobiology to support the claims.     

Socializing the newcomer: The mediating role of leader–member exchange

We expand organizational socialization research by integrating social exchange theory, specifically leader–member exchange (LMX), as an important mediator in explaining newcomer attachment to the job, occupation, and organization. Using temporally-lagged data from 213 newcomers across 12 telemarketing organizations, we found that newcomer perceptions of LMX mediate the association between supervisory socialization tactics (i.e. supervisory job-focused advice, guidance, and role modeling) and occupational identification as well as between supervisory socialization tactics and perceived person-organization fit – but not between supervisory socialization tactics and job satisfaction. Our study specifies (1) LMX as a compelling mediating mechanism within the new employee ‘on-boarding’ process and (2) the immediate supervisor as an important relational source for newcomer attitudes.     

The role of learning in risk-avoidance strategies during spider–ant interactions

Cognitive abilities used by arthropods, particularly predators, when interacting in a natural context have been poorly studied. Two neotropical sympatric predators, the golden silk spider Nephila clavipes and the ectatommine ant Ectatomma tuberculatum, were observed in field conditions where their interactions occurred regularly due to the exploitation of the same patches of vegetation. Repeated presentations of E. tuberculatum workers ensnared in their web triggered a progressive decrease in the capture response of N. clavipes. All the spiders that stopped trying to catch the ant on the second and/or third trial were individuals that had been bitten during a previous trial. Behavioural tests in natural field conditions showed that after a single confrontation with ant biting, spiders were able to discriminate this kind of prey more quickly from a defenceless prey (fruit flies) and to selectively and completely suppress their catching response. This one-trial aversive learning was still effective after 24 h. Likewise, E. tuberculatum workers entangled once on a N. clavipes web and having succeeded in escaping, learned to escape more quickly, breaking through the web by preferentially cutting spiral threads (sticky traps) rather than radial threads (stronger structural unsticky components) or pursuing the cutting of radials but doing it more quickly. Both strategies, based on a one-trial learning capability, obviously minimize the number of physical encounters between the two powerful opponents and may enhance their fitness by diminishing the risk of potential injuries resulting from predatory interactions.     

The role of closure in defining the “objects” of object-based attention

Many recent studies have concluded that the underlying units of visual attention are often discrete objects whose boundaries constrain the allocation of attention. However, relatively few studies have explored the particular stimulus cues that determine what counts as an “object” of attention. We explore this issue in the context of the two-rectangles stimuli previously used by many investigators. We first show, using both spatial-cuing and divided-attention paradigms, that same-object advantages occur even when the ends of the two rectangles are not drawn. This is consistent with previous reports that have emphasized the importance of individual contours in guiding attention, and our study shows that such effects can occur in displays that also contain grouping cues. In our divided-attention experiment, however, this contour-driven same-object advantage was significantly weaker than that obtained with the standard stimulus, with the added cue of closure—demonstrating that contour-based processes are not the whole story. These results confirm and extend the observation that same-object advantages can be observed even without full-fledged objects. At the same time, however, these studies show that boundary closure—one of the most important cues to objecthood per se—can directly influence attention. We conclude that object-based attention is not an all-or-nothing phenomenon; object-based effects can be independently strengthened or weakened by multiple cues to objecthood.     

The role of modeling processes in the “knee deep in the big muddy” phenomenon

Entrapping conflicts are characterized by the tendency for individuals to make increasing commitments to some failing course of action, in large part to justify the appropriateness of previous investments made in that situation. It has been suggested that (1) these dilemmas frequently arise in organizational settings, and (2) whether decision makers escalate their commitment or withdraw from a failing course of action can be affected by a variety of factors. The present four experiments were designed to determine if an individual's degree of entrapment (i.e., tendency to escalate) may be affected by the behavior of a model in a similar situation. In Experiments 1–3, considerable generality was obtained for the proposition that decision makers in entrapping conflicts can be directly influenced by a model. Individuals who witnessed an entrapped model became significantly more entrapped than those who did not. This effect was obtained (1) for subjects and models of both sexes, (2) on measures of both process and outcome, (3) across two different experimental procedures, and (4) when the model was viewed either during or before the time that subjects were called upon to make their decisions. Experiments 3 and 4 delineated several limiting conditions of the modeling-entrapment relationship. Participants did not invest more of their resources in the presence than in the absence of an entrapped model if the model expressed regret rather than pleasure about his behavior. In fact, under such conditions a significant “reverse modeling” effect was obtained, in which subjects became less entrapped in the presence of the entrapped model. The modeling-entrapment relationship was also significantly reduced when the model was unlikable and unintelligent, and thus not an appropriate person for comparison. Theoretical and practical implications are discussed, including the possibility that models may be skillfully employed to help decision makers stop “throwing good money after bad.”