Role of motor processes in extrinsically encoding mental transformations

Previous research has shown that imagined perspective rotations elicit spatial and low-level cortical motor areas of the brain when participants rely on knowledge of their physical body, or body percept (Wraga, Flynn, Boyle, & Evans, 2010). The current study used functional magnetic resonance imaging (fMRI) to investigate whether recruitment of the body percept would activate low-level cortical motor areas of the brain within other classes of mental transformations. Participants performed imagined object and perspective rotations of three-dimensional Shephard-Metzler (1971) stimuli. For each task, participants used button presses serving as virtual pointers to locate a prescribed portion of the stimuli with respect to their "right" and "left." We found low-level cortical motor activation (M1) for both mental transformations; however, the degree to which such activation related to participants' performance differed, as well as the recruitment of additional nonmotoric strategies. The results are discussed in terms of recent hypotheses regarding the role of the body percept in extrinsically encoded mental transformations.     

Bimanual reaching across the hemispace: Which hand is yoked to which?

When both hands perform concurrent goal-directed reaches, they become yoked to one another. To investigate the direction of this coupling (i.e., which hand is yoked to which), the temporal dynamics of bimanual reaches were compared with equivalent-amplitude unimanual reaches. These reaches were to target pairs located on either the left or right sides of space; meaning that in the bimanual condition, one hand's contralateral (more difficult) reach accompanied by the other hand's ipsilateral (easier) reach. By comparing which hand's difficult reach was improved more by the presence of the other hand's easier ipsilateral reach, we were able to demonstrate asymmetries in the coupling. When the cost of bimanual reaching was controlled for the contralateral reaching left hand's performance was improved, suggesting that the left hand is yoked to the right during motor output. In contrast, the right hand showed the greatest improvements for contralateral reaching in terms of reaction time, pointing toward a dominant role for the left hand in the processes prior to movement onset. The results may point toward a mechanism for integrating the unitary system of attention with bimanual coordination.     

The effect of attending to motor overflow on its voluntary inhibition in young and older adults

Motor overflow refers to involuntary movement or muscle activity coinciding with voluntary movement. We examined whether 16 young adults (18-30 years) and 16 older adults (50-80 years) could voluntarily inhibit overflow. Participants performed a finger pressing task, exerting 50% of their maximal force. Overflow was concurrently recorded in the non-task hand. In the first condition, participants were not made aware of their motor overflow. Then participants, though informed of it, were asked to ignore their overflow. Finally, participants were requested to inhibit overflow with, and then without visual feedback, or vice versa. Overflow was exacerbated when older adults were unaware of it, and was reduced once they were informed. For young adults there was no significant difference between these conditions. Both Age Groups could significantly reduce overflow when so requested, independent of visual feedback. Thus motor overflow can be modulated by higher order cognitive control with directed attention.     

Fitts’ law holds for pointing movements under conditions of restricted visual feedback

Fitts’ law robustly predicts the time required to move rapidly to a target. However, it is unclear whether Fitts’ law holds for visually guided actions under visually restricted conditions. We tested whether Fitts’ law applies under various conditions of visual restriction and compared pointing movements in each condition. Ten healthy participants performed four pointing movement tasks under different visual feedback conditions, including full-vision (FV), no-hand-movement (NM), no-target-location (NT), and no-vision (NV) feedback conditions. The movement times (MTs) for each task exhibited highly linear relationships with the index of difficulty (r² > .96). These findings suggest that pointing movements follow Fitts’ law even when visual feedback is restricted or absent. However, the MTs and accuracy of pointing movements decreased for difficult tasks involving visual restriction.     

Hand dominance influences the processing of observed bodies

In motor tasks, subgroups of lefthanders have been shown to differ in the distribution of attention about their own bodies. The present experiment examined whether similar attentional biases also apply when processing observed bodies. Sixteen right handers (RHs), 22 consistent left handers (CLHs) and 11 relatively ambidextrous inconsistent left handers (ILHs) performed an own body transformation task in which they were instructed to make speeded left–right judgements about a schematic human figure. Attentional biases associated with handedness were found to extend to observed bodies: CLHs’ judgements were faster to the figure’s left side, while ILHs, like RHs, showed facilitated performance to the figure’s right side. These results demonstrate a novel embodiment effect whereby the processing of a static schematic human figure is modulated by an individual’s personal motor capabilities. This finding suggests that motor simulation may contribute to whole body perception in the absence of actual or implied actions.     

判断与决策中的规划谬误

规划谬误是指人们在估计未来任务的完成时间时, 倾向于过度乐观, 低估任务完成时间的一种现象。规划谬误的心理机制主要包括规划谬误理论和记忆偏差理论。规划谬误的影响因素主要有认知因素、动机因素、个体的经验水平、目标任务的性质等。规划谬误的应对策略主要有与过去的经验相联系、从第三人称视角进行估计、任务分解及时间分配。未来的研究主要从规划谬误与策略性误解、乐观偏差、过分自信的关系, 规划谬误的产生根源、规划谬误的跨文化研究、规划谬误的研究范围及应用领域等方面进一步探讨。     

年幼儿童的尺寸匹配误差现象

近十年来,尺寸匹配误差作为年幼儿童生活中的一种常见的尺寸误用现象逐渐受到了一些研究者的关注。现有研究主要集中在尺寸匹配误差的特点、出现频率和产生原因等方面。抑制控制的失败、神经通路的协调失败、“计划-控制”模型和“感觉-行动”模型、功能性推理偏好以及身体意识发展的不成熟等观点能够对某些类型的尺寸匹配误差现象做出解释。未来的研究应从进一步深入探讨尺寸匹配误差与假装的区别、完善研究方法以及跨文化研究的开展几方面进行。     

口语句子产生中词汇选择的计划单元：来自大中小学生的比较研究

采用图-词干扰范式,要求被试口语产生包含三个名词的句子,通过检验句中不同位置的名词上的语义干扰效应, 探讨大中小学生言语产生中词汇选择的计划单元。结果发现,大学生和初中生都只在第一个名词上发现了言语产生潜伏期的语义干扰效应,表明其词汇选择的计划单元只限于第一个名词,支持了严格递进假设;小学生在三个名词上都没有发现潜伏期的语义干扰效应,表明小学生没有稳定地选择好第一个名词即开始发音。由此可见,词汇选择的计划单元大小是可变的,存在年龄上的个体差异,主要表现在小学生和初中生之间。     

Perceptual-attentional and motor-intentional bias in near and far space

Spatial bias demonstrated in tasks such as line-bisection may stem from perceptual-attentional (PA) "where" and motor-intentional (MI) "aiming" influences. We tested normal participants' line bisection performance in the presence of an asymmetric visual distracter with a video apparatus designed to dissociate PA from MI bias. An experimenter stood as a distractor to the left or right of a video monitor positioned in either near or far space, where participants viewed lines and a laser point they directed under (1) natural and (2) mirror-reversed conditions. Each trial started with the pointer positioned at either the top left or top right corner of the screen, and alternated thereafter. Data analysis indicated that participants made primarily PA leftward errors in near space, but not in far space. Furthermore, PA, but not MI, bias increased bilaterally in the direction of distraction. In contrast, MI, but not PA, bias was shifted bilaterally in the direction of startside. Results support the conclusion that a primarily PA left sided bias in near space is consistent with right hemisphere spatial attentional dominance. A bottom-up visual distractor specifically affected PA "where" spatial bias while top-down motor cuing influenced MI "aiming" bias.     

Differential Effects of Strategic Planning on Community Change in Two Urban Neighborhood Coalitions

Community coalitions represent a promising approach for addressing the interrelated and multiply- determined issues affecting urban neighborhoods of concentrated poverty. The literature suggests a number of community processes that may affect coalition efforts to change and improve communities. This study uses an interrupted time-series design to examine the effects of a strategic planning intervention on community change in two urban neighborhoods in the Kansas City metropolitan area. Results showed that strategic planning was associated with increased rates of community change in the two urban neighborhood coalitions. Under appropriate conditions, such as the presence of consistent leadership, strategic planning may be a particularly effective mechanism for stimulating community change and addressing locally-determined goals in urban neighborhoods.