The effect of external perturbations on variability in joint coupling and single joint variability

This paper explores the effect of goal-oriented external perturbations created by elastic tubes attached to the hip and ankles on lower limb joint variability and hip–knee and knee–ankle coordination variability during running. Kinematics of ten healthy male runners were analysed prior to and following a 7-week tube running intervention while running with and one without this constraint. The training intervention was based on variable training aspects to increase within-movement variability and adaptability of the running pattern. To analyse the effects of the tubes on the running pattern, the phase plot vector length deviation (i.e., the standard deviation of the phase plot vector length) for the within-joint variability and the continuous relative phase variability for the joint coupling variability were calculated. Results revealed acute increases of variability in both parameters. However, after the intervention, variability of the tube running situation returned to normal for all couplings and joints except the knee. No transfer effects to normal running were observed. This suggests very rapid adaptations to such perturbations. In the long-term, it may ask for more or different variations.     

Utility of gambling under p(olynomial)-additive joint receipt and segregation or duplex decomposition

This article continues our exploration of the utility of gambling, but here under the assumption of a non-additive but p(olynomial)-additive representation of joint receipt. That assumption causes the utility of gambling term to have a multiplicative impact, rather than just an additive one, on what amounts to ordinary weighted utility. Assuming the two rational recursions known as branching and upper gamble decomposition, we investigate separately the rational property of segregation and the non-rational one of duplex decomposition. Under segregation, we show that each pair of disjoint events either exhibits weight complementarity or both support no utility of gambling, a property called UofG-singular. We develop representations for both cases. The former representation is a simple weighted utility with each term multiplied by a function of the event underlying that branch. The latter representation is an ordinary rank-dependent utility with Choquet weights but with no utility of gambling. Under duplex decomposition, we show that weights have the intuitively unacceptable property that there is essentially no dependence upon the events, making duplex decomposition, in this context, of little behavioral interest.     

The effect of receipt personalization on tipping behavior

Research has shown that personalizing receipts, such as drawing “smiley faces” and writing “thank you” notes on customer bills to express gratitude, can result in larger tips for restaurant wait staff. Although the practice of receipt personalization has been supported using field experiments, limited research has examined the effectiveness of this technique based on the level of service quality provided by restaurant wait staff. Using a scenario‐based approach, we found from this study that adding a personalized message significantly lowers tip percentages. Moreover, the negative effect is magnified when service quality fails to exceed customer expectations. Implications related to the findings are discussed. Copyright © 2013 John Wiley & Sons, Ltd.     

The good of today depends not on the good of tomorrow: a constraint on theories of well-being

Philosophical Studies - This article addresses three questions about well-being. First, is well-being future-sensitive? I.e., can present well-being depend on future events? Second, is well-being...     

A note on the standard length of a test

This paper describes a relationship between the variance-covariance matrix of test items and Woodbury's concept of the standard length of a test. An index of item-test relationship is described in standard length terms. The sum of these indices for the items in a test is equal to the square of Jackson's coefficient of sensitivity.     

Effects of the coronavirus pandemic on perceived capitalization support provision and receipt

The coronavirus pandemic has influenced relationship dynamics due to heightened stress, increased isolation, and the need for social distancing. Prior work suggests receiving support for positive events (“capitalization support”) during this time could boost well-being, but only if it is provided in a manner that is active (involved) and constructive (supportive), as opposed to passive (uninvolved) and/or destructive (discouraging). Given the need for reduced social contact, we predicted the pandemic would make providing active, constructive support more challenging and might increase the frequency of passive support. We conducted two studies to explore how perceptions of capitalization methods may have shifted during the pandemic using an online participant pool (MTurk). Overall, we found that participants reported receiving significantly less active-constructive capitalization support and receiving more passive-constructive support during the pandemic (compared to pre-pandemic perceptions). In addition, we found that those who reported receiving and providing more active-constructive support tended to report more positive well-being outcomes. Interestingly, passive-constructive support was also associated with greater well-being for recipients (counter to prior research that has shown it associated with only costs). Overall, our data suggests that capitalization support perceptions are associated with well-being even during the pandemic, but methods of capitalization support perceived may have shifted during the pandemic.     

Control of velocity and position in single joint movements

Previous research on single joint movements has lead to the development of models of control that propose that movement speed and distance are controlled through an initial pulsatile signal that can be modified in both amplitude and duration. However, the manner in which the amplitude and duration are modulated during the control of movement remains controversial. We now report two studies that were designed to differentiate the mechanisms used to control movement speed from those employed to control final position accuracy. In our first study, participants move at a series of speeds to a single spatial target. In this task, acceleration duration (pulse-width) varied substantially across speeds, and was negatively correlated with peak acceleration (pulse-height). In a second experiment, we removed the spatial target, but required movements at the three speeds similar to those used in the first study. In this task, acceleration amplitude varied extensively across the speed targets, while acceleration duration remained constant. Taken together, our current findings demonstrate that pulse-width measures can be modulated independently from pulse-height measures, and that a positive correlation between such measures is not obligatory, even when sampled across a range of movement speeds. In addition, our findings suggest that pulse-height modulation plays a primary role in controlling movement speed and specifying target distance, whereas pulse-width mechanisms are employed to correct errors in pulse-height control, as required to achieve spatial precision in final limb position.     

Giving the sceptic a good name

The word ‘sceptic’ usually refers to a theoretical figure whose philosophical importance lies exclusively in his challenge to any attempt to justify the belief in the possibility of knowledge. But the label was once applied to living persons ‐ the so‐called Pyrrhonists ‐ whose scepticism encompassed a way of life. Following Sextus Empiricus's portrayal of the Pyrrhonists, Arne Naess has provided comprehensive arguments both in rebuttal of the frequent claims either that scepticism is logically inconsistent or that at least it is impossible to put into practice, and in support of scepticism as a fruitful philosophical attitude. The present essay attempts a critical consolidation of Naess's case for scepticism by drawing more explicitly than he does on his work in empirical semantics. The notion of degrees of preciseness is used to outline a philosophically interesting rationale for the Pyrrhonist's persistent abstention from any act or action that commits him to the truth of a proposition, and also to indicate why possible, or even inevitable lapses on the Pyrrhonist's part need not seriously prejudice either his status as a sceptic or the philosophical value of his sceptical ideal.     

Presenting two color words on a single Stroop trial: evidence for joint influence,not capture

MacLeod and Hodder (1998) demonstrated that presenting two different incongruent color words in the same color on a single Stroop trial resulted in no more interference than did presenting the same incongruent color word twice, and concluded that the first word captured attention, blocking out the second. They also showed that, within a trial, neither stimulus onset asynchrony between the two items nor the presence/absence of a visible gap between the two items had any effect. We replicated all of their empirical findings. Then, by extending their design and factorially combining three types of items--incongruent words, congruent words, and control nonwords--within a trial, we demonstrated that both items within a trial do influence processing, with the contribution of the second greater than that of the first. These results are incompatible with a capture account and suggest instead that the word dimension continues to be monitored during the attempt to identify and produce the name of the color.     

A note on the computation of a table of intercorrelations

Outlined is the method used at present by the Educational Testing Service for computing intercorrelations from basic summations. This procedure is adapted to the use of high speed calculators in performing the calculations, and much of its value lies in the complete system of checks that is a part of the method. Besides the correlations that are the object of the procedure, covariances, means, standard deviations, and the number of cases are also recorded on the completed form to be available for further statistical steps.     

Views of a good life and allostatic load: Physiological correlates of theories of a good life depend on the socioeconomic context

This research examines the relationship between one’s theory of a good life and allostatic load, a marker of cumulative biological risk, and how this relationship differs by socioeconomic status. Among adults with a bachelor’s degree or higher, those who saw individual characteristics (e.g. personal happiness, effort) as part of a good life had lower levels of allostatic load than those who did not. In contrast, among adults with less than a bachelor’s degree, those who saw supportive relationships as part of a good life had lower levels of allostatic load than those who did not. These findings extend past research on socioeconomic differences in the emphasis on individual or relational factors and suggest that one’s theory of a good life has health implications.