Tests of sphericity of normal distributions and the analysis of repeated measures designs

The locally best invariant test statistic for testing sphericity of normal distributions is shown to be a simple function of the Box/Geisser-Greenhouse degrees of freedom correction factor in a repeated measures design. Because of this relationship it provides a more intuitively appealing test of the necessary and sufficient conditions for valid F-tests in repeated measures analysis of variance than the likelihood ratio test. The properties of the two tests are compared and tables of the critical values of the Box/Geisser-Greenhouse correction factor are given.     

BEHAVIORAL TREATMENT OF CAFFEINISM: REDUCING EXCESSIVE COFFEE DRINKING

Excessive coffee drinking can have deleterious effects because of the large amounts of caffeine that are ingested. Caffeine is thought to be addicting, and prolonged and excessive use can lead to caffeinism, a condition that has serious behavioral and physiological side effects. The present study developed and evaluated a treatment program to reduce excessive daily coffee drinking to moderate and presumably safer levels. Three habitual coffee drinkers received individualized changing criterion programs that systematically and gradually reduced their daily caffeine intake. The coffee drinkers were required to self-monitor and plot their daily intake of caffeine. They received monetary prizes for not exceeding the treatment phase criteria and forfeited a portion of their pretreatment deposit when they did. Their coffee drinking decreased from almost nine cups per day (over 1100 mg of caffeine) during baseline to less than three cups per day (less than 343 mg) at the end of treatment or a reduction of 69%. The treatment effect was maintained during a 10-month follow-up, averaging a 67% reduction from baseline. The program appears to be a reasonable method of reducing and then maintaining daily caffeine intake at less harmful levels.     

Effects of serial versus concurrent task sequencing an acquisition, maintenance, and generalization

Effects of serial and concurrent task presentation on skill acquisition, generalization, and maintenance were compared. Two severely retarded females participated. During serial training, items of one response class, tracing, were trained to mastery before those of a second task, vocal imitation. In the concurrent method, training on two different tasks, tracing and vocal imitation, alternated within sessions for fixed periods of time. There were no major differences between the serial and concurrent methods of instruction in the number of steps attained per behavior or in the number of trials required to reach criterion levels of performance. It was found however, that concurrent training resulted in more generalization. Retention results were not consistently related to training method.     

Multiple-probe technique: a variation on the multiple baseline

Multiple-baseline and probe procedures are combined into a “multiple-probe” technique. The technique is designed to provide a thorough analysis of the relationship between an independent variable and the acquisition of a successive-approximation or chain sequence. It provides answers to the following questions: (1) What is the initial level of performance on each step in the training sequence? (2) What happens if sequential opportunities to perform each next step in the sequence are provided before training on that step? (3) What happens when training is applied? (4) What happens to the performance of remaining steps in the sequence as criterion is reached in the course of training each prior step? The technique features: (1) one initial probe of each step in the training sequence, (2) an additional probe of every step after criterion is reached on any training step, and (3) a series of “true” baseline sessions conducted just before the introduction of the independent variable to each training step. Intermittent probes also provide an alternative to continuous baseline measurement, when such measurement during extended multiple baselines (1) may prove reactive, (2) is impractical, and/or (3) a strong a priori assumption of stability can be made.     

TOWARD A METHODOLOGY OF WITHDRAWAL DESIGNS FOR THE ASSESSMENT OF RESPONSE MAINTENANCE

Single-case experimental designs have advanced considerably in the evaluation of functional relationships between interventions and behavior change. The systematic investigation of response maintenance once intervention effects have been demonstrated has, however, received relatively little attention. The lack of research on maintenance may stem in part from the paucity of design options that systematically evaluate factors that contribute to maintenance. The present paper discusses three design options potentially useful for the investigation of response maintenance. These include: (a) the sequential-withdrawal, (b) the partial-withdrawal, and (c) the partial-sequential withdrawal designs. Each design is illustrated and potential limitations are discussed.     

多种因素对时间连续阈限的影响

该研究做了两个实验,研究了七个因素——刺激的类型、刺激的复杂度、刺激的强度、刺激的呈现时间、被试对两刺激的判断标准、同一种感觉道的个数、性别——对时间连续阈限的影响.在实验一中,结果表明,刺激的类型、刺激的呈现时间、被试对两刺激的判断标准和同一种感觉道的个数四个因素对时间连续阈限有显著影响,而刺激的复杂度、刺激的强度和性别三个因素对时间连续阈限没有显著影响。在实验二中,结果表明,在影响显著的四个因素之间不存在交互作用。     

Longitudinal changes in term and preterm infant night wakings: The role of caregiver anxious-depression

Changes in infant night waking during the first year of life are associated with individual (e.g., prematurity) and family (e.g., caregiver psychopathology) factors. This study examined the association between infant night waking and caregiver anxious-depressive symptoms during the first year of life in preterm and term infants. We considered between-person differences and within-person changes in caregiver anxious-depressive symptoms in relation to changes in infant night waking from 2- to 9-months. Racially (30.0% Black, 60.4% White, 9.5% multiracial/other) and socioeconomically (40.0% below median household income) diverse caregivers (N = 445) of full term (n = 258) and preterm (n = 187) infants were recruited from hospitals and clinics in two midwestern states. Caregivers completed measures of anxious-depression and their infant's night waking at four sampling periods (2-, 4-, 6-, and 9-months). Infant night wakings declined from 2- to 9-months. Between-person differences were observed, such that caregivers with higher average anxious-depressive symptoms or infants born full term reported more night wakings. Within-person effects of caregiver anxious-depressive symptoms were not significant. Caregiver anxious-depression is closely associated with infant night wakings. By considering a caregiver's average severity of anxious-depression, healthcare providers can more effectively plan infant sleep interventions. If caregiver anxious-depressive symptoms are ameliorated, night wakings may also decrease.     

先秦服饰色彩与现代服装设计

民族风格的服装一直是现代服装设计主要潮流,中华民族有着悠久的服饰文化历史,一些民族的元素或多或少地也出现一些现代设计中,但总的来说,不是很系统。服装设计的继承不能只停留在形制的模仿上,而是要从文化的层面上融会传统服饰的精髓,用神似的手法进行设计。本文分析了中华服饰的色彩文化的形成和色彩文化的哲学基础。从先民对色彩的认识、色彩的运用和染色技术等方面论证,显示了中华民族优秀的服饰文明,同时也给我们在现代服装设计中色彩的运用提供了很好的启示。     

How drivers adapt their behaviour to changes in task complexity: The role of secondary task demands and road environment factors

The present study investigates the impact of different sources of task complexity such as driving demands and secondary task demands on driver behaviour. Although much research has been dedicated to understanding the impact of secondary task demands or specific road traffic environments on driving performance, there is little information on how drivers adapt their behaviour to their combined presence. This paper aims to describe driver behaviour while negotiating different sources of task complexity, including mobile phone use while driving (i.e., calling and texting) and different road environments (i.e., straight segments, curves, hills, tunnels, and curves on hills). A driving simulator experiment was conducted to explore the effects of different road scenarios and different types of distraction while driving. The collected data was used to estimate driving behaviour through a Generalized Linear Mixed Model (GLMM) with repeated measures. The analysis was divided into two phases. Phase one aimed to evaluate driver performance under the presence and absence of pedestrians and oncoming traffic, different lanes width and different types of distraction. The second phase analysed driver behaviour when driving through different road geometries and lane widths and under different types of distraction. The results of the experiment indicated that drivers are likely to overcorrect position in the vehicle lane in the presence of pedestrians and oncoming traffic. The effect of road geometry on driver behaviour was found to be greater than the effect of mobile phone distraction. Curved roads and hills were found to influence preferred speeds and lateral position the most. The results of this investigation also show that drivers under visual-manual distraction had a higher standard deviation of speed and lateral position compared to the cognitive distraction and the non-distraction condition.