Identifying living and sentient kinds from dynamic information: the case of goal-directed versus aimless autonomous movement in conceptual change

To reason competently about novel entities, people must discover whether the entity is alive and/or sentient. Exactly how people make this discovery is unknown, although past researchers have proposed that young children--unlike adults--rely chiefly on whether the object can move itself. This study examined the effect of goal-directed versus aimless autonomous movement on children's and adults' attributions of biological and psychological capacities in an effort to test whether goal-directedness affects inferences across documented periods of change in biological reasoning. Half of the participants (adults, and 4-, 5-, 7-, and 10-year-olds; Ns=32) were shown videos of unfamiliar blobs moving independently and aimlessly, and the other half were shown videos of identical blobs moving identically but toward a goal. No age group was likely to attribute biological or psychological capacities to the aimless self-moving blobs. However, for 5-year-olds through adults, goal-directed movement reliably elicited life judgments, and it elicited more biological and psychological attributions overall. Adults differed from children in that goal-directed movement affected their attributions of biological properties more than their attributions of psychological properties. The results suggest that both young children and adults consider the capacity for goal-directed movement to be a decisive factor in determining whether something unfamiliar is alive, though other factors may be important in deciding whether the thing is sentient.     

Effect of Transient Perturbations of Short-Term Memory on Target-Directed Blind Locomotion

It is difficult to walk without vision to a nearby destination if there is a time delay between watching the destination and walking toward it. Indeed, path deviation occurred when delays were introduced before initiating straight ahead blindfolded walking (R. A. Tyrrell, K. K., Rudolph, B. G., Eggers, &; H. W. Leibowitz, 1993 Tyrrell, R. A., Rudolph, K. K., Eggers, B. G., &; Leibowitz, H. W. (1993). Evidence for the persistence of visual guidance information. Perception &; Psychophysics, 54, 431–438.[Crossref], [PubMed] , [Google Scholar]). The questions are whether the location of a 60-s delay in the walking path and whether performing a cognitive task during the delay influence the accuracy in reaching a previously seen target while walking without vision. Thirty young adults walked blindfolded and stopped when they believed they had reached a target at 8 m. Delays were 60 s in duration, were located at 0, 4, and 7 m, and involved waiting or backward counting. Significant differences were found between 0-m and 4-m delay locations for distance to target, distance travelled and path deviation (p < .05). Significant effect of backward counting during the 60-s delay was found at the 0-m delay for distance travelled (p < .05). The interaction between retaining visual guidance information during 60 s and performing a cognitive task likely influenced target-directed blind navigation.     

汉字表象加工中的心理位移研究

自谢帕德等首次进行心理旋转实验以来,表象加工方式的研究主要集中在心理旋转、心理扫描和认知地图等方面,而作为另一种加工方式的心理位移尚未有研究。本研究以人造汉字作为研究材料,试图证实在表象加工过程中存在心理位移加工方式,结果证实心理位移是表象的加工方式之一。在心理位移过程中,反应时间与构成新形象的两种刺激表象之间的呈现距离成正比;汉字构字过程中心理位移所需加工时间的临界点可能是0．5-1秒。     

Spatial memory in the grey mouse lemur (Microcebus murinus)

Wild animals face the challenge of locating feeding sites distributed across broad spatial and temporal scales. Spatial memory allows animals to find a goal, such as a productive feeding patch, even when there are no goal-specific sensory cues available. Because there is little experimental information on learning and memory capabilities in free-ranging primates, the aim of this study was to test whether grey mouse lemurs (Microcebus murinus), as short-term dietary specialists, rely on spatial memory in relocating productive feeding sites. In addition, we asked what kind of spatial representation might underlie their orientation in their natural environment. Using an experimental approach, we set eight radio-collared grey mouse lemurs a memory task by confronting them with two different spatial patterns of baited and non-baited artificial feeding stations under exclusion of sensory cues. Positional data were recorded by focal animal observations within a grid system of small foot trails. A change in the baiting pattern revealed that grey mouse lemurs primarily used spatial cues to relocate baited feeding stations and that they were able to rapidly learn a new spatial arrangement. Spatially concentrated, non-random movements revealed preliminary evidence for a route-based restriction in mouse lemur space; during a subsequent release experiment, however, we found high travel efficiency in directed movements. We therefore propose that mouse lemur spatial memory is based on some kind of mental representation that is more detailed than a route-based network map. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Vertical adaptation of the center of mass in human running on uneven ground

In running we are frequently confronted with different kinds of disturbances. Some require quick reactions and adaptations while others, like moderate changes in ground level, can be compensated passively. Monitoring the kinematics of the runner’s center of mass (CoM) in such situations can reveal what global locomotion control strategies humans use and can help to distinguish between active and passive compensation methods.In this study single and permanent upward steps of 10 cm as well as drops of the same height were used as mechanical disturbances and the adaptations in the vertical oscillation of the runners CoM were analyzed. We found that runners visually perceiving uneven ground ahead substantially adapted their CoM in preparation by lifting it about 50% of step height or lowering it by about 40% of drop height, respectively. After contact on the changed ground level different adaptations depending on the situation occur. For persisting changes the adaptation to the elevated ground is completed after the first step on the new level. For single steps part of the adaptation takes place while returning to the ground. The consistent adaptations for the different situations support the idea that controlling the CoM by adapting leg parameters is a general control principle in running.     

The Continuing Saga of the Nerve Compression Block Technique

In response to Bairstow and Laszlo (1976) the present paper points out the inconsistencies of their arguments relative to Laszlo’s previous work and that of Kelso, Stelmach, and Wanamaker (1974). Data are presented indicating that the nerve compression block, as a tool, fails to meet the stringent requirements necessary for examining motor performance in the absence of kinesthetic information. Some possibilities for the discrepancy between Laszlo’s performance data and those from Kelso et al. are discussed. These hinge on the availability of sensory information rather than any artifact in the Kelso et al. nerve conduction procedures as Bairstow and Laszlo (1976) suggest.     

Effects of Gradual Versus Sudden Training on the Cognitive Demand Required While Learning a Novel Locomotor Task

The cognitive demand required for a range of locomotor tasks has been described for a variety of populations. However, the effect of different training strategies on the cognitive demand required while learning novel locomotor tasks is not well understood and may inform physical rehabilitation. The authors examined whether two training strategies, gradual and sudden training, influenced the cognitive demand required while practicing a novel locomotor task, asymmetric split-belt treadmill walking. Simple reaction times and whole-body kinematics were recorded throughout practice. Gradual training resulted in significantly lower reaction times during much of training, suggesting that gradual training is less cognitively demanding than sudden training, possibly due to a reduction in error feedback or movement planning demands.     

Simulated Visual Field Loss Does Not Alter Turning Coordination in Healthy Young Adults

Turning, while walking, is an important component of adaptive locomotion. Current hypotheses regarding the motor control of body segment coordination during turning suggest heavy influence of visual information. The authors aimed to examine whether visual field impairment (central loss or peripheral loss) affects body segment coordination during walking turns in healthy young adults. No significant differences in the onset time of segments or intersegment coordination were observed because of visual field occlusion. These results suggest that healthy young adults can use visual information obtained from central and peripheral visual fields interchangeably, pointing to flexibility of visuomotor control in healthy young adults. Further study in populations with chronic visual impairment and those with turning difficulties are warranted.     

Speed Modulation in Swimming Frogs

Swimming movements of 7 European green frogs (Rana esculenta) were studied, starting from the detailed analysis of the speed and timing of the propulsive, glide, and recovery phases of their intermittent swimming behavior. First, the authors identified the spatiotemporal factors used by the frogs to modulate their swimming behavior. None of the gait variables correlated strongly with average swimming speed, and no significant correlations were found between variables belonging to different phases. There did not seem to be an obvious control strategy. Instantaneous speeds at the transition of the different phases all increased significantly with average speed, however. The strong correlation between maximal speed at the end of propulsion and the speed averaged over a cycle might reflect the dominance of the propulsive phase in the determination of the overall swimming speed. The modulation of swimming speed thus seemed largely comparable with the regulation of jumping distance. That finding was confirmed in a mathematical model, in which the positive correlations between both glide and recovery speeds, on the one hand, and average speed, on the other, were shown to be only mathematical consequences of the strong impact of the propulsive phase on overall swimming performance. That finding suggests that the correlations did not result from an active control strategy.     

脂多糖免疫激活导致抑郁性行为的动物研究：剂量和时程效应

“抑郁症细胞因子假说”的提出为抑郁障碍的病因学研究提供了一个新的方向,为了探讨脂多糖（lipopolyaccharide,LPS）诱导的免疫激活与抑郁性行为产生之间的关系,本研究采用50只SD大鼠随机分为五组LPS400,LPS200,LPS50,LPS10,LPS0,分别于实验期第0天和第3天注入LPS400ug/kg,,200ug/kg,50ug/kg,10ug/kg和生理盐水。以糖精水偏爱,旷场行为和高架十字迷宫评定大鼠LPS注射后2小时,24小时,48小时的行为变化。结果显示一次LPS注射后2小时,LPS50,LPS200,LPS400组动物与生理盐水组动物相比较,其糖精水偏爱分数（p<0.01）,旷场中的水平活动距离(p<0.01)和直立行为(p<0.01)以及高架十字迷宫中的闭合臂进入次数(p<0.01)和开放臂进入次数显著下降(p<0.01);重复注射后2小时LPS注射组动物的闭合臂进入次数显著降低（p<0.01）;但LPS10组与生理盐水组动物在行为上没有差异,50ug/kg,200ug/kg和400ug/kg剂量的各组之间没有差异。LPS注射后24小时和48小时以及重复注射后大鼠的行为没有发现显著变化。提示LPS诱导的免疫激活对抑郁行为产生有一定的作用。免疫激活的细胞因子能够导致动物出现明显的抑郁性行为,但是这种行为缺乏长时程效应,因此LPS诱导的抑郁障碍的动物模型应用是非常有限的。免疫激活的前炎性细胞因子可能是导致抑郁障碍产生的其中一个原因而不是唯一原因。