Consistent haptic feedback is required but it is not enough for natural reaching to virtual cylinders

In virtual reality it is easy to control the visual cues that tell us about an object's shape. However, it is much harder to provide realistic virtual haptic feedback when grasping virtual objects. In this study we examined the role of haptic feedback when grasping (virtual) cylinders with an elliptical circumference. In Experiment 1 we placed the same circular cylinder at the simulated location of virtual elliptical cylinders of varying shape, so that the haptic feedback did not change when the visually specified shape changed. We found that the scaling of maximum grip aperture with the diameter of the nearest principal axis (.14+/-.04) was much weaker than when grasping real cylinders (.54+/-.04, Cuijpers, Brenner, & Smeets, 2006 Grasping reveals visual misjudgements of shape. Experimental Brain Research, 175, 32-44). For the scaling of grip orientation with the orientation of the cylinder we found large individual differences: the range is .07-.82 (average .42+/-.07) as compared to .55-.79 (average .67+/-.03) for grasping real cylinders. In Experiment 2 we provided consistent haptic feedback by placing real cylinders that matched the location, shape and orientation of the virtual cylinders. The scaling gains of both maximum grip aperture (.39+/-.04) and grip orientation (.56+/-.08) were substantially higher than in Experiment 1, but still lower than for grasps to real cylinders. The variability between participants for the scaling of grip orientation was also much reduced. These results showed that although haptic feedback must be consistent with visual information, it is not sufficient for natural prehension. We discuss the implications of these findings in terms of the integration of visual information with haptic feedback.     

The role of white matter hyperintensities and medial temporal lobe atrophy in age-related executive dysfunctioning

Various studies support an association between white matter hyperintensities (WMH) and deficits in executive function in nondemented ageing. Studies examining executive functions and WMH have generally adopted executive function as a phrase including various functions such as flexibility, inhibition, and working memory. However, these functions include distinctive cognitive processes and not all may be affected as a result of WMH. Furthermore, atrophy of the medial temporal lobe (MTA) is frequently observed in ageing. Nevertheless, in previous studies of nondemented ageing MTA was not considered when examining a relationship between white matter and executive function. The goal of the present study was to examine how WMH and MTA relate to a variety of executive functions, including flexibility, fluency, inhibition, planning, set shifting, and working memory. Strong correlations were observed between WMH and MTA and most of the executive functions. However, only MTA was related to flexibility and set shifting performance. Regression analysis furthermore showed that MTA was the strongest predictor of working memory, after which no further significant association with WMH was noted. Alternatively, both MTA and periventricular hyperintensities independently predicted inhibition performance. These findings emphasize the importance of MTA when examining age-related decline in executive functioning.     

Striving for optimal relevance when answering questions

When people are asked "Do you have the time?" they can answer in a variety of ways, such as "It is almost 3", "Yeah, it is quarter past two", or more precisely as in "It is now 1:43". We present the results of four experiments that examined people's real-life answers to questions about the time. Our hypothesis, following previous research findings, was that people strive to make their answers optimally relevant for the addressee, which in many cases allows people to give rounded, and not exact, time responses. Moreover, analyses of the non-numeral words, hesitations, and latencies of people's verbal responses to time questions reveal important insights into the dynamics of speaking to achieve optimal relevance. People include discourse markers, hesitation marks, like "uh" and "um", and pauses when answering time questions to maximize the cognitive effects (e.g., a rounded answer is adequate) listeners can infer while minimizing the cognitive effort required to infer these effects. This research provides new empirical evidence on how relevance considerations shape collaborative language use.     

Incremental validity of the Psychopathy Checklist facet scores: predicting release outcome in six samples

The incremental validity of the 4 facet scores (Interpersonal, Affective, Lifestyle, Antisocial) of the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991, 2003) and the Psychopathy Checklist: Screening Version (PCL:SV; S. D. Hart, D. N. Cox, & R. D. Hare, 1995) was evaluated in 6 forensic/correctional samples with average follow-ups ranging from 20 weeks to 10 years. Results indicated that whereas Facet 4 (Antisocial) achieved incremental validity relative to the first 3 facets (Interpersonal, Affective, and Lifestyle) in predicting recidivism in all 6 samples, a block of the first 3 facets achieved incremental validity relative to the 4th facet in only 1 sample. Thus, although there was consistent support for the incremental validity of Facet 4 above and beyond the first 3 facets, there was minimal support for the incremental validity of Facets 1, 2, and 3 above and beyond Facet 4. The implications of these findings for the psychopathy construct in general and the PCL-R/SV in particular are discussed.     

Abdominal exercise intensities on firm and compliant surfaces

Muscle activities at 15 sites were compared within a group of healthy young adults to evaluate their relative intensities during six abdominal exercises: partial and full sit-ups on a firm surface (floor) and on an exercise ball that was either stabilized or unstabilized. The most strenuous abdominal exercise overall (i.e., whole body workout) was the full sit-up on a firm surface which included significant muscle activities in the lower extremities. Exercise intensity was also high in the full and partial sit-ups when performed on a ball. The partial sit-up on the floor was the least strenuous of the six exercises. The greatest effect on the abdominal muscles was observed in the partial sit-up on a ball (stabilized and unstabilized). Results suggest that, although abdominal exercises on a ball may be gentler on the hip and lower back, overall exercise intensity is not necessarily lower than that on the floor. Moreover, partial sit-ups, both on the floor and on a ball, also required greater neck muscle activities than full sit-ups. In deciding what type of sit-up to do, exercise surface and different muscular activities between the partial and full sit-ups should be considered.     

An investigation of the effects of dog visits on depression,mood, and social interaction in elderly individuals living in a nursing home

The present study investigated the effects of weekly dog visits on depression scores, mood, and social interaction in elderly individuals living in a nursing home. Five elderly residents participated in baseline assessments for 4–8 weeks and then received weekly dog visits for 6 weeks. Assessments, consisting of weekly observations of social interaction and paper and pencil measures of mood and depression, continued during the dog visits. The effect of dog visits was evaluated in a multiple baseline across participants design. Dog visits did not improve depression scores, mood (with the exception of one resident), or social interaction (with the exception of one resident). Residents did interact with the dog during the visits, however, and reported that they enjoyed the visits. These results show that dog visits do not always have therapeutic effects and suggest the need for further research in the area before the beneficial effects of dog visits can be substantiated. Copyright © 2008 John Wiley & Sons, Ltd.     

The Function of Fiction is the Abstraction and Simulation of Social Experience

ABSTRACT— Fiction literature has largely been ignored by psychology researchers because its only function seems to be entertainment, with no connection to empirical validity. We argue that literary narratives have a more important purpose. They offer models or simulations of the social world via abstraction, simplification, and compression. Narrative fiction also creates a deep and immersive simulative experience of social interactions for readers. This simulation facilitates the communication and understanding of social information and makes it more compelling, achieving a form of learning through experience. Engaging in the simulative experiences of fiction literature can facilitate the understanding of others who are different from ourselves and can augment our capacity for empathy and social inference.     

精神分裂症谱系中的快感缺乏

快感缺乏, 指体验愉快能力的降低, 它在精神分裂症病因学中发挥着很重要的作用, 其存在增加了罹患精神分裂症谱系疾病的风险。然而, 精神分裂症中做情绪体验的快感缺乏研究由于方法学的问题常不能得到一致的结果。从奖励系统入手, 最新的研究证据支持精神分裂症期待性愉快损伤, 而消费性愉快相对完好。在分裂型人格中似乎也存在类似的损伤模式。该文从精神分裂症谱系的角度, 探讨了从奖励系统考察快感缺乏的可能。