材料数量与呈现速度对视、听同时瞬时记忆的影响

视、听材料同时识记、瞬时记忆效果并非普遍降低。材料数量影响视、听同时瞬时记忆效果的变化及其方向;无意义联系汉字数量超记忆广度时,视、听同时瞬时记忆相对效果与非同时识记相比提高。材料数量也影响视、听同时瞬时记忆的相对优势及重现方式。这些结果倾向于表明,材料数量在记忆广度内及超记忆广度时,视、听同时瞬时记忆的组织加工不同。呈现速度只影响记忆优势及重现方式。根据多项分析,可以认为视、听通道标签是组织视、听同时瞬时记忆最鲜明的标签,经过识记5个视、听同时字表,视、听同时识记效果有提高趋势。     

Humean dispositionalism

Humean metaphysics is characterized by a rejection of necessary connections between distinct existences. Dispositionalists claim that there are basic causal powers. The existence of such properties is widely held to be incompatible with the Humean rejection of necessary connections. In this paper I present a novel theory of causal powers that vindicates the dispositionalist claim that causal powers are basic, without embracing brute necessary connections. The key assumptions of the theory are that there are natural types of causal processes, and that manifestations of powers are identified with certain kinds of causal processes. From these assumptions, the modal features of powers are explained in terms of internal relations between powers themselves and the process-types in which powers are manifested.     

Tests of statistical hypotheses in the case of unequal or disproportionate numbers of observations in the subclasses

General solutions of the analysis of variance in the case of unequal numbers of observations in the subclasses are presented. If we havek criteria for the classification, there will bek! solutions in making a complete analysis and 2^k–1 answers, bearing different meanings, for the sum of squares between subclasses of each criterion. The sum of squares for the interaction of any order, however, will be identical in different solutions of same problem.     

Factorial design and covariance in the study of individual educational development

This is the report of the application of the principles of factorial design to an investigation of individual educational development. The specific type of factorial design formulated was a 2 × 3 × 3 × 3 arrangement, that is, the effect of sex, grade location, scholastic standing, and individual order, singly and in all possible combinations was studied in relation to educational development as measured by theIowa Tests of Educational Development. An application of the covariance method was introduced which resulted in increased precision of this type of experimental design by significantly reducing experimental error. The two concomitant measures used to increase the sensitiveness of the experiment were initial status of individual development and mental age. Without these statistical controls all main effects and two first-order interactions would have been accepted as significant. With their use only sex (doubtful), scholastic standing, and individual order demonstrated significant effects. The chief beauty of the analysis of variance and covariance as an integral part of a self-contained experiment is demonstrated in the complete single analysis of the data. The statistical utilization of the experimental results has also been developed for purposes of estimation and prediction. The mathematical statistician is being continuously required to develop and analyze experimental designs of increasing complexity since the introduction of the analysis of variance and covariance. The mathematical formulation and solution of the problem of this investigation is carried out. The methods illustrated and explained in this study, and modifications and extensions of them are capable of very wide application. The general principles can be used to various degrees and in a number of ways.For the research grant to finance this study, grateful acknowledgment is given to the Graduate School, the University of Minnesota.     

Acoustic analysis of lexical tone in Mandarin infant-directed speech

Using Mandarin Chinese, a "tone language" in which the pitch contours of syllables differentiate words, the authors examined the acoustic modifications of infant-directed speech (IDS) at the syllable level to test 2 hypotheses: (a) the overall increase in pitch and intonation contour that occurs in IDS at the phrase level would not distort lexical pitch at the syllable level and (b) IDS provides exaggerates cues to lexical tones. Sixteen Mandarin-speaking mothers were recorded while addressing their infants and addressing an adult. The results indicate that IDS does not distort the acoustic cues that are essential to word meaning at the syllable level; evidence of exaggeration of the acoustic differences in IDS was observed, extending previous findings of phonetic exaggeration to the lexical level.     

Impact of language anxiety and self-efficacy on accessing Internet sites.

Language interface plays a critical role as the foundation of communication. Possessing greater fluency in the host language can lead to increased opportunities for interaction with host members. This research is to examine the impact of language and Internet usage anxiety and self-efficacy on the intended uses of Internet sites, respectively. By the same token, whether Internet/language self-efficacy would mediate the effects of Internet/language anxiety on the intention of the Internet site use is also examined. A valid sample of 368 undergraduates was tested in this study. The path analysis results mostly supported the model tested. The results display that the anxiety of language and Internet use have significantly influenced self-efficacy of Internet use and language, respectively. Anxiety about language and Internet use have also significantly influenced the intention to use Internet sites individually. Furthermore, language self-efficacy has significantly influenced the intention to use Internet sites, but Internet self-efficacy has not. The implications are discussed at the end of the paper.     

Probing the limits of tool competence: Experiments with two non-tool-using species (Cercopithecus aethiops and Saguinus oedipus)

Non-human animals vary in their ability to make and use tools. The goal of the present study was to further explore what, if anything, differs between tool-users and non-tool-users, and whether these differences lie in the conceptual or motor domain. We tested two species that typically do not use tools-cotton top tamarins (Saguinus oedipus) and vervet monkeys (Cercopithecus aethiops)-on problems that mirrored those designed for prolific tool users such as chimpanzees. We trained subjects on a task in which they could choose one of two canes to obtain an out-of-reach food reward. After training, subjects received several variations on the original task, each designed to examine a specific conceptual aspect of the pulling problem previously studied in other tool-using species. Both species recognized that effective pulling tools must be made of rigid materials. Subsequent conditions revealed significant species differences, with vervets outperforming tamarins across many conditions. Vervets, but not tamarins, had some recognition of the relationship between a tool's orientation and the position of the food reward, the relationship between a tool's trajectory and the substance that it moves on, and that tools must be connected in order to work properly. These results provide further evidence that tool-use may derive from domain-general, rather than domain-specific cognitive capacities that evolved for tool use per se.