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181.
Effect of contraction intensity [100%, 75%, 50%, and 25% maximum voluntary contraction (MVC)] and movement velocity [0 degrees (isometric)], 50 degrees, 100 degrees, 200 degrees, and 400 degrees/sec. [isovelocities]) on root mean square amplitude (SEMG-RMS) and median frequency power spectrum (SEMG-MNF) of vastus lateralis (VL) surface electromyography was investigated with ten healthy female university students. Peak torque (PT), mean torque (MT), SEMG-MNF, and SEMG-RMS, analyzed using separate repeated-measures analyses of variance (p < or = .05), indicated: (1) an inverse relation between PT and MT and movement velocity, (2) greater SEMG-MNF values during all isovelocity conditions compared with isometric conditions, with highest values occurring at 50 degrees /sec. and at 100% and 75% MVC, and (3) at all contraction intensities SEMG-RMS values were higher during dynamic movements than isometric movements and highest at 200 degrees /sec. Isovelocity contractions were inferred to facilitate a greater recruitment of fast-twitch fibers (via increased SEMG-MNF), which was intensified at 50 degrees /sec., whereas greater overall muscle activation was found at 200 degrees /sec. 相似文献
182.
Miguez G Witnauer JE Miller RR 《Journal of experimental psychology. Animal behavior processes》2012,38(1):40-51
Three conditioned suppression experiments with rats as subjects assessed the contributions of the conditioned stimulus (CS)-context and context-unconditioned stimulus (US) associations to the degraded stimulus control by the CS that is observed following partial reinforcement relative to continuous reinforcement training. In Experiment 1, posttraining associative deflation (i.e., extinction) of the training context after partial reinforcement restored responding to a level comparable to the one produced by continuous reinforcement. In Experiment 2, posttraining associative inflation of the context (achieved by administering unsignaled outcome presentations in the context) enhanced the detrimental effect of partial reinforcement. Experiment 3 found that the training context must be an effective competitor to produce the partial reinforcement acquisition deficit. When the context was down-modulated, the target regained behavioral control thereby demonstrating higher-order retrospective revaluation. The results are discussed in terms of retrospective revaluation, and are used to contrast the predictions of a performance-focused model with those of an acquisition-focused model. 相似文献
183.
Julie Poehlmann AJ Miller Schwichtenberg Emily Hahn Kyle Miller Janean Dilworth‐Bart David Kaplan Sarah Maleck 《Infant mental health journal》2012,33(1):34-44
Although children born preterm or low birth weight (PT LBW) are more likely to exhibit behavior problems compared to children born at term, developmental and family processes associated with these problems are unclear. We examined trajectories of maternal depressive symptoms in relation to toddler compliance and behavior problems in families with PT LBW infants. A total of 177 infants (93 boys, 84 girls) and their mothers enrolled in the study during the infant's NICU stay. Data were collected at five time points across 2 years. Assessments of maternal depressive symptoms were conducted at all time points, and toddler compliance and opposition to maternal requests and behavior problems were assessed at 2 years. Toddlers born earlier with more health problems to mothers whose depressive symptoms increased over time exhibited the most opposition to maternal requests during a cleanup task at 24 months, consistent with multiple risk models. Mothers with elevated depression symptoms reported more behavior problems in their toddlers. The study has implications for family‐based early intervention programs seeking to identify PT LBW infants at highest risk for problem behaviors. 相似文献
184.
Actions that do not have as their goal the advancement or protection of one's material interests are often seen as illegitimate. Four studies suggested that moral values can legitimate action in the absence of material interest. The more participants linked sociopolitical issues to moral values, the more comfortable they felt advocating on behalf of those issues and the less confused they were by others' advocacy (Studies 1 and 2). Crime victims were perceived as being more entitled to claim special privileges when the crime had violated their personal moral values (Studies 3 and 4). These effects were strongest when the legitimacy to act could not already be derived from one's material interests, suggesting that moral values and material interest can represent interchangeable justifications for behavior. No support was found for the possibility that attitude strength explained these effects. The power of moralization to disinhibit action is discussed. 相似文献
185.
We present and test a theory in which self-control is distinguished from broader acts of self-regulation when it is both effortful and conscious. In two studies, we examined whether acts of behavioral management that do not require effort are exempt from resource depletion. In Study 1, we found that a self-regulation task only reduced subsequent self-control for participants who had previously indicated that completing the task would require effort. In Study 2, we found that participants who completed a self-regulation task for two minutes did not evidence the subsequent impairment in self-control evident for participants who had completed the task for four or more minutes. Our results support the notion that self-regulation without effort falls below the self-control threshold and has different downstream consequences than self-control. 相似文献
186.
Same-race (SR) faces are recognized better than other-race (OR) faces, and this other-race effect (ORE) is correlated with experience. SR faces are also processed more holistically than OR faces, suggesting one possible mechanism for poorer performance on OR faces. Studies of object expertise have shown that individuating experiences are necessary for holistic processing to develop; yet thus far no studies have investigated the role of quality of experience and the ORE for holistic processing. In the present study, we found a strong negative correlation between a self-report of individuating experience and the ORE in holistic processing in both Caucasian and Black participants, indicating that the more individuating experience a person has, the less ORE in holistic processing. This confirms the critical role of individuating experience in development of holistic processing for faces and suggests that quality of experience is a key determinant of the manner in which OR faces are processed. 相似文献
187.
Although labeling improves executive function (EF) performance in children older than 3 years, the results from studies with younger children have been equivocal. In the current study, we assessed performance in a computerized multistep multilocation search task with older 2-year-olds. The correct search location was either (a) not marked by a familiar picture or given a distinct label, (b) marked by a familiar picture but not given a distinct label, (c) marked by a familiar picture and labeled by the experimenter, or (d) marked by a familiar picture and labeled by the participant. The results revealed that accuracy improved across conditions such that children made the fewest errors when they generated the label for the hiding location. These findings support the hierarchical competing systems model, which postulates that improved performance can be explained by more powerful representations that guide search behavior. 相似文献
188.
This study investigates the importance of vowel diacritics for the retention of Hebrew word lists, with word lists being manipulated
along the dimension of word frequency and syllabic length. Eighty university students participated in the study. Half of the
participants (40) were tested with the word lists presented in fully-pointed (voweled) Hebrew while the other half (40) were
given the word lists in unpointed Hebrew (with vowel diacritics removed). Analyses of each group’s recall rates and recall-order
accuracy indicate that, overall, the presence of vowel diacritics had no facilitating effect on the participants’ quantitative
and qualitative Short Term Memory (STM) performance. This was found to be true whether word frequency (high vs. medium to
low) or syllabic length (mono vs. trisyllabic) were computed as within-subject factors. Attempts to adequately interpret the
absence of a pointing effect on STM performance based upon Orthographic Depth Hypothesis (ODH) and Grain Size Theory (GST)
proved unfruitful. The authors propose an adaptation of the GST to the peculiarities of Hebrew orthography and discuss a morphology-centered
grain-size theory (MGST). 相似文献
189.
190.
A good sense of humor is sexually attractive, perhaps because it reveals intelligence, creativity, and other ‘good genes’ or ‘good parent’ traits. If so, intelligence should predict humor production ability, which in turn should predict mating success. In this study, 400 university students (200 men and 200 women) completed measures of abstract reasoning (Raven's Advanced Progressive Matrices), verbal intelligence (the vocabulary subtest of the Multidimensional Aptitude Battery), humor production ability (rated funniness of captions written for three cartoons), and mating success (from the Sexual Behaviors and Beliefs Questionnaire). Structural equation models showed that general and verbal intelligence both predict humor production ability, which in turn predicts mating success, such as lifetime number of sexual partners. Also, males showed higher average humor production ability. These results suggest that the human sense of humor evolved at least partly through sexual selection as an intelligence-indicator. 相似文献