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971.
This article studies undergraduate students journeys in volunteering, and details the motivations of and challenges that these volunteers face during the journey. We conducted five focus groups on a total of 38 undergraduate volunteers, and obtained seven themes as we undertook an investigation of our three research questions. Our findings revolved around these seven themes, which ranged from motivations to experiences to challenges. Our findings have helped us understand the motivations and challenges that undergraduate volunteers have and face during the journey of volunteering. Some of these challenges are particular to a university setting, but some others can certainly be generalized to other settings. Recommendations for future research are also included.  相似文献   
972.
Spatial attention can be reflexively captured by a physically salient stimulus, effortfully directed toward a relevant location, or involuntarily oriented in the direction of another person's gaze (i.e., social gaze orienting). Here, we used event-related potentials to compare the effects of these three types of orienting on multiple stages of subsequent target processing. Although gaze orienting has been associated more strongly with reflexive capture than with voluntary attention, the present data provide new evidence that the neural effects of social gaze orienting are markedly different from the effects of reflexive attentional capture by physically salient stimuli. Specifically, despite their similar behavioral effects, social gaze orienting and reflexive capture produce different effects on both early sensory processing (~120 ms; P1/N1 components) and later, higher-order processing (~300 ms; P3 component). In contrast, the effects of social gaze orienting were highly similar to those of voluntary orienting at these stages of target processing.  相似文献   
973.
How do retinal images lead to perceived environmental objects? Vision involves a series of spatial and material transformations—from environmental objects to retinal images, to neurophysiological patterns, and finally to perceptual experience and action. A rationale for understanding functional relations among these physically different systems occurred to Gustav Fechner: Differences in sensation correspond to differences in physical stimulation. The concept of information is similar: Relationships in one system may correspond to, and thus represent, those in another. Criteria for identifying and evaluating information include (a)?resolution, or the precision of correspondence; (b)?uncertainty about which input (output) produced a given output (input); and (c)?invariance, or the preservation of correspondence under transformations of input and output. We apply this framework to psychophysical evidence to identify visual information for perceiving surfaces. The elementary spatial structure shared by objects and images is the second-order differential structure of local surface shape. Experiments have shown that human vision is directly sensitive to this higher-order spatial information from interimage disparities (stereopsis and motion parallax), boundary contours, texture, shading, and combined variables. Psychophysical evidence contradicts other common ideas about retinal information for spatial vision and object perception.  相似文献   
974.
975.
Visual search for feature targets was employed to investigate whether the mechanisms underlying visual selective attention are modulated by observers’ mood. The effects of induced mood on overall mean reaction times and on changes and repetitions of target-defining features and dimensions across consecutive trials were measured. The results showed that reaction times were significantly slower in the negative than in the positive and neutral mood groups. Furthermore, the results demonstrated that the processing stage that is activated to select visual information in a feature search task is modulated by the observer’s mood. In participants with positive or neutral moods, dimension-specific, but no feature-specific, intertrial transition effects were found, suggesting that these observers based their responses on a salience signal coding the most conspicuous display location. Conversely, intertrial effects in observers in a negative mood were feature-specific in nature, suggesting that these participants accessed the feature identity level before responding.  相似文献   
976.
977.
Two ordinal consequences are drawn from the linear multiple-factor analysis model. First, the numberR(s, d) of distinct ways in whichs subjects can be ranked by linear functions ofd factors is limited by the recursive expressionR(s, d)=R(s?1,d)+(s?1)R(s?1,d?1). Second, every setS ofd+2 subjects can be separated into two subsetsS* andS ? S* such that no linear function ofd variables can rank allS* over allS ? S*, and vice versa. When these results are applied to the hypothetical data of Thurstone's “box problem,” three independent parameters are found. Relations to Thurstone's suggestion for a non-correlational factor analysis are discussed.  相似文献   
978.
979.
Using a joystick, adults (n = 39 males, 40 females in Experiment 1; n = 35 males, 40 females in Experiment 2; and n = 18 males, 18 females in Experiment 3) performed a computerized pursuit tracking task. Contrary to previously reported findings, the males were not more accurate than the females when performance was adjusted for prior perceptual-motor experience. Although no sex differences were found in a speeded tracking task, in an inverted tracking task the males exhibited a significant performance advantage; that advantage remained after several blocks of practice. Because participants' performance was adjusted statistically for prior perceptual-motor experience, the male advantage in inverted tracking was not related to experience. Rather, more proficient inverted tracking performance was associated with higher 3-dimensional mental rotations scores. In sum, sex differences in normal pursuit tracking may be better explained by differences in perceptual-motor experience. Inverted tracking, however, may depend on proficiency with spatial transformations.  相似文献   
980.
This paper challenges an implicit assumption of analytical psychology that centred, mandalic images express psychical wholeness in an optimal fashion across cultures and eras. I suggest that liminal, bardo-like eras, such as our 'post-modern' one, constellate complex, antithetical and ec-centric images, which are process-oriented and which encompass wholeness and fragmentation, conjunction and disjunction, thus holding and expressing actual individual and collective experience. In our era, we inhabit unfolding states of wholeness, brokenness and fragmentation. Images of wholeness, emerging spontaneously from the unconscious, may reflect part or all of these contradictory realities. Examples of such antithetical Self-images are developed from the ancient midrashic traditions of the rabbis; from Jung's contemporary exposition of Pauli's 'world-clock' dream; from Kepler's discovery, at the dawn of modernity, that the planets circled the sun in ellipses rather than circles; and from a clinical illustration.  相似文献   
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