Emergence of Concrete Operational Concepts

In Piagetian and neo-Piagetian literature, there have been conflicting results of experiments made to predict the order in which the concrete operational concepts of Class Inclusion, Transitive Inference, and Conservation emerge in a child. The present study determined the order in which these concepts emerged among 94 male and 84 female Canadian children between the ages of 5 and 7 (N = 178). Overall results indicated that Class Inclusion emerged first, followed by Transitive Inference, and then Conservation. This was the pattern for 6-year-olds, whereas 5- and 7-year-olds performed Class Inclusion and Transitive Inference at the same level of efficiency. Thus, it is apparent that Class Inclusion is generally the easiest concept to be attained, and Conservation is the most difficult. This study also indicates that the order of emergence varies and depends on the background and previous experience of the subjects.     

The relational determination of length illusions and length aftereffects.

When two lines were presented simultaneously, in an illusion paradigm, the judged length of one of the lines (the focal line) assimilated toward the length of the contextual line. When the lines were presented sequentially, in an aftereffect paradigm, the apparent length of the focal line was displaced away from the length of a previously presented contextual line (i.e. contrast). The largest effects obtained at inverse contextual-to-focal length ratios: 1.67:1 for contextual lines longer than the focal line and 0.60:1 for contextual lines shorter than the focal line. Overestimation of focal length was larger than underestimation for both illusions and aftereffects despite the fact that identical stimuli produced effects in opposite directions in the two paradigms. Results were discussed in terms of a neural length-coding model and were related to visual size constancy.     

A computational analysis of conservation

An approach to modeling cognitive development with a generative connectionist algorithm is described and illustrated with a new model of conservation acquisition. Among the conservation phenomena captured with this model are acquisition, the problem size effect, the length bias effect, and the screening effect. The simulations suggest novel explanations for sudden jumps in conservation performance (based on new representations of conservation transformations) and for the problem size effect (based on an analog representation of number). The simulations support the correlation-learning explanation of length bias (that length correlates with number during number altering transformations). Some conservation phenomena that so far elude computational modeling attempts are also discussed along with their prospects for capture. Suggestions are made for theorizing about cognitive development as well as about conservation acquisition. A variety of classic puzzles about cognitive development are addressed in the light of this model and similar models of other aspects of cognitive development.     

Homonym understanding and conservation

It is proposed that a common cognitive capacity underlies both homonym understanding and conservation ability—namely, the capacity to shift attention from one dimension (domain) to another. This hypothesis is tested in a longitudinal study of kindergarten (mean age 6-0) and first-grade (mean age 6-6) children. The results indicate that conservation status is significantly related to homonym understanding, over and above the age or general vocabulary level of the child.     

Two varieties of perceived length

The perception of length depends on the mode of stimulation. When Ss were asked to judge the apparent lengths of blocks presented either visually or proprioceptively (between thumb and finger of one hand), visual length was proportional to block length, whereas proprioceptive length was an accelerating function of block length. When both visual and proprioceptive stimulation occurred simultaneously (S both saw and felt a block), the visual input was preemptive.     

健康促进志愿者的运行机制研究

新的社区卫生规划中,社区卫生服务内容越发广泛,伴随着新医改的深入,社区卫生服务人力资源缺乏,服务盲点多而分散,医患衔接不畅等问题日益突出.以重庆市江北区的健康促进志愿者为例,分析志愿服务对于社区卫生的影响,并对建立健全志愿服务的机制做一定的分析.     

Similarity judgments of line length

Nine Ss judged similarity of pairs of lines on a scale from 0 to 100, and 14 Ss made magnitude estimations of similarity of pairs of lines. The two scales of similarity were linearly related. Scale values for subjective length were obtained in one dimension using a nonmetric multidimensional analysis. Subjective length was found to be logarithmically related to objective length, and similarity was found to be an exponential     

An Ethical Decision-Making Model for Operational Psychology

Operational psychology is an emerging subdiscipline that has enhanced the U.S. military's combat capabilities during the Global War on Terrorism. What makes this subdiscipline unique is its use of psychological principles and skills to improve a commander's decision making as it pertains to conducting combat (or related operations). Due to psychology's expanding role in combat support, psychologists are being confronted with challenges that require the application of their professional ethics in areas in which little if any guidance has been provided. Operational psychologists are at the forefront of this expansion. Accordingly, they need a decision model to assist them in this complex dynamic environment. To this end, this article reviews various decision models and ethical frameworks, selects the most appropriate, and then applies it to the challenges faced by operational psychologists. A naturalistic decision model that integrates rational and intuitive elements is recommended.