Gradations of emulation learning in infants' imitation of actions on objects

This study explored different gradations of emulation in the imitation of actions on objects by 17-month-olds. Experiment 1 established levels of behavioral reproduction following prerecorded video demonstrations similar to those levels following live demonstrations. In Experiment 2, two digitally modified videos, where object movements or body movements critical to producing the target action were highlighted in isolation, were developed. Infants produced the target action equally frequently by observing the object movement video and observing the unmodified video. In contrast, their performance was much less successful based on the body movement video. In Experiment 3, the performance obtained following the object movement video was similar to that following a further video that emphasized the object movements produced in unsuccessful attempts to produce the target action. These findings suggest that emulation in the form of object movement reenactment or affordance learning plays a role in the social learning of actions on objects during infancy.     

Roll-over characteristics of human walking on inclined surfaces

Roll-over characteristics of able-bodied human subjects walking on ramped surfaces were examined in this study. Ten subjects walked at their normal self-selected speed on a level surface, a 5-deg ramp, and a 10-deg ramped surface. Ramps were designed such that ground reaction forces and center of pressure of the ground reaction forces could be measured on their surfaces. This set-up facilitated calculation of the effective rockers that the ankle-foot (AF) and knee-ankle-foot (KAF) systems conformed to during single-limb stance (contralateral toe off to contralateral heel contact). Since our original "roll-over shapes" were characterized between heel contact and opposite heel contact, we label the shapes found during single-limb stance as "truncated roll-over shapes". We hypothesized that the ankle-foot system would adapt to the various surfaces, creating a roll-over shape that would change in orientation with different levels of inclination. The truncated AF roll-over shapes supported this hypothesis for uphill walking but did not support the hypothesis for downhill walking. However, truncated roll-over shapes of the KAF system did adjust their orientation to match both the positive and negative levels of surface inclination. In general, the ankle appears to be the main adapting joint when walking up inclined surfaces while the knee becomes important for the overall adaptation in downhill walking. Knowledge of physiological lower-limb roll-over characteristics on ramped surfaces may help in the development of biomimetic prostheses and orthoses that will automatically adapt to changes in walking surface inclination.     

Sustainable Pressure for "Women-Friendliness" in Sweden

This paper describes how Swedish women argue and act in order to improve their quality of life. It is based on a citizen survey and on interviews with leaders of a broadly defined women's movement. The thesis is that women are in the process of developing their own democratic practice. They thereby challenge the assumption that general suffrage and numerical equality of representation are sufficient conditions for transforming the contemporary gender power order into one characterized by equality of power between women and men. The empirical data show that there is a great deal of variation in perceptions of problems and ways of accomplishing change. The existence of somewhat different priorities and plural feminist strategies for change—state feminist, interest group–based, civil, and segregated—are interpreted as speaking in favor of the sustainability of such pressure for "women-friendliness" in Sweden.     

The Timing of Conscious Experience: A Critical Review and Reinterpretation of Libet''s Research

An extended examination of Libet's works led to a comprehensive reinterpretation of his results. According to this reinterpretation, the Minimum Train Duration of electrical brain stimulation should be considered as the time needed to create a brain stimulus efficient for producing conscious sensation and not as a basis for inferring the latency for conscious sensation of peripheral origin. Latency for conscious sensation with brain stimulation may occurafterthe Minimum Train Duration. Backward masking with cortical stimuli suggests a 125–300 ms minimum value for the latency for conscious sensation of threshold skin stimuli. Backward enhancement is not suitable for inferring this latency. For determining temporal relations between stimuli that correspond to subjects' reports, theendof cerebral Minimum Train Duration should be used as reference, rather than its onset. Results of coupling peripheral and cortical stimuli are explained by a latency after the cortical Minimum Train Duration, having roughly the same duration as the latency for supraliminal skin stimuli. Results of coupling peripheral stimuli and stimuli to medial lemniscus (LM) are explained by a shorter LM latency and/or a longer peripheral latency. This interpretation suggests a 230 ms minimum value for the latency for conscious sensation of somatosensory near-threshold stimuli. The backward referral hypothesis, as formulated by Libet, should not be retained. Long readiness potentials preceding spontaneous conscious or nonconscious movements suggest that both kinds of movement are nonconsciously initiated. The validity of Libet's measures of W and M moments (Libet et al., 1983a) is questionable due to problems involving latencies, training, and introspective distinction of W and M. Veto of intended actions may be initially nonconscious but dependent on conscious awareness.     

Historical misrepresentation in science: The case of fetal alcohol syndrome

The history of the fetal alcohol syndrome (FAS) provides a microcosm in which to explore the larger ramifications of historical citations in biomedical publications. Though some historical references such as Biblical writings may hint at a rudimentary understanding of the relationship between maternal drinking and fetal development, no definitive case can be made for an understanding of FAS dating back hundreds of years. Authors who claim an impressive history for FAS misrepresent that history. The modern history of FAS raises a question concerning citations of original discoveries. The first paper describing ethanol-induced damage to the fetus appeared in 1968 yet most researchers cite one of two papers from 1973. Both ancient citations and modern references to original discoveries pose difficult questions for the scientist. Both dilemmas may be solved by a better reading of the literature and a more judicious wording when writing about history. This work was supported in part by Grant # AA10681 to SNP.     

胎教音乐对胎儿影响的实验研究

该项研究从三个方面探讨了胎教音乐对胎儿的作用。结果发现：胎教音乐可以使胎动时间延长,并证明在胎儿后期即存在条件反射;胎儿出生后能够再认胎教音乐,说明在胎儿后期已经存在听觉记忆;胎儿的性别及神经活动类型是影响其对音乐反应的重要因素。该研究的意义在于：证明了胎儿期心理现象的存在。把对“胎儿期有无心理现象”的历史争论引入了心理学的实验过程。     

Revolution and the counter-revolution: The conflict over meaning between P. B. Struve and S. L. Frank in 1922

Lecturer in the Lomonossov University, Moscow, specialist in the young Hegel; has also worked quite extensively on Russian prerevolutionary thought. Nikolaj Plotnikov is notably the co-editor of the recently re-published texts,Vekhi, Iz Glubiny in the collection 'Iz istorii oteestvennoj filosofskoj mysli' in conjunction withVoprosy Filosofii.     

BEHAVIOR ANALYSIS OF MOTION CONTROL FOR PEDIATRIC NEUROIMAGING

Magnetic resonance imaging is a promising technological advance used for research and diagnosis of disease. The procedure has no risks, except when uncooperative patients require sedation. Four normal children participated in simulated scans to study the effects of (a) antecedent changes in the imaging environment and (b) operant conditioning of movement inhibition. Changing the environment can decrease movement, but operant contingencies were necessary to decrease movement to a level that, in most cases, would allow the procedure to occur without sedation.     

驾驶员的动态反应时研究

本研究应用DFY-1型动态反应时测试仪,以解放CA10B 型卡车为实验用车,结合日常运输任务,对三种年龄组(20—29岁、30—39岁、40—49岁)的30名驾驶员,在三种车速(静态,30公里/小时及50公里/小时)条件下的反应时、动作时及制动反应时进行了测试。结果表明:车速对驾驶员的反应时及制动反应时有显著影响,而对动作时则无显著影响;驾驶员的年龄对反应时、动作时及制动反应时均无显著影响.本研究结果为加强驾驶员的安全教育与管理,控制车速提供了佐证。更高车速条件下驾驶员的反应时特点尚待进一步研究。     

Correlation between performance and quantity/variability of leg exploration in a contingency learning task during infancy

Quantity and quality of motor exploration are proposed to be fundamental for infant motor development. However, it is still not clear what types of motor exploration contribute to learning. To determine whether changes in quantity of leg movement and/or variability of leg acceleration are related to performance in a contingency learning task, twenty 6–8-month-old infants with typical development participated in a contingency learning task. During this task, a robot provided reinforcement when the infant’s right leg peak acceleration was above an individualized threshold. The correlation coefficient between the infant’s performance and the change in quantity of right leg movement, linear variability, and nonlinear variability of right leg movement acceleration from baseline were calculated. Simple linear regression and multiple linear regression were calculated to explain the contribution of each variable to the performance individually and collectively. We found significant correlation between the performance and the change in quantity of right leg movement (r = 0.86, p < 0.001), linear variability (r = 0.71, p < 0.001), and nonlinear variability (r = 0.62, p = 0.004) of right leg movement acceleration, respectively. However, multiple linear regression showed that only quantity and linear variability of leg movements were significant predicting factors for the performance ratio (p < 0.001, adjusted R² = 0.94). These results indicated that the quantity of exploration and variable exploratory strategies could be critical for the motor learning process during infancy.