Relative sensitivity to reinforcer amount and delay in a self-control choice situation.

Rats were exposed to concurrent-chains schedules in which a single variable-interval schedule arranged entry into one of two terminal-link delay periods (fixed-interval schedules). The shorter delay ended with the delivery of a single food pellet; the longer day ended with a larger number of food pellets (two under some conditions and six under others). In Experiment 1, the terminal-link delays were selected so that under all conditions the ratio of delays would exactly equal the ratio of the number of pellets. But the absolute duration of the delays differed across conditions. In one condition, for example, rats chose between one pellet delayed 5 s and six pellets delayed 30 s; in another condition rats chose between one pellet delayed 10 s and six pellets delayed 60 s. The generalized matching law predicts indifference between the two alternatives, assuming that the sensitivity parameters for amount and delay of reinforcement are equal. The rats' choices were, in fact, close to indifference except when the choice was between one pellet delayed 5 s and six pellets delayed 30 s. That deviation from indifference suggests that the sensitivities to amount and delay differ from each other depending on the durations of the delays. In Experiment 2, rats chose between one pellet following a 5-s delay and six pellets following a delay that was systematically increased over sessions to find a point of indifference. Indifference was achieved when the delay to the six pellets was approximately 55 s. These results are consistent with the possibility that the relative sensitivities to amount and delay differ as a function of the delays.     

Infantile colic and parental experiences

The study comprised two groups of 33 parents each, one whose infants were identified by parents as colicky during their first 3 months and one with non-colicky infants. Parents filled out a questionnaire with one set of questions about parental experiences when infants were 3 months old and a set of parallel questions concerning current experiences (infant age 8-11 months). The results showed that the 3-month situation was more negatively described with regard to both infant behaviour and parental experiences by the parents of colicky infants. For the current situation (8-11 months), there were no significant group differences, meaning that no long-lasting effects could be demonstrated. However, in the colic group amount of crying and difficulty in comforting during the colic period were significantly related to current parental satisfaction, which suggests that these aspects of infant behaviour and experienced parental competence are of importance also in a longer perspective.     

Development of a pleasure in parenting scale

Two major components of parenting have been identified: warmth and control. There has been a great deal of work on the measurement of control, but there are not many measures of parental warmth. As part of an attempt to develop better measures of warmth, we developed a scale measuring parents' pleasure in carrying out routine caretaking acts with their children. This measure was then related to other measures of positive support such as observation, observer ratings and questionnaires. As there is evidence in the literature that quality of the environment interacts with parenting, we related the measure to measures of stress, observer ratings of quality of the home, marital interaction and parental mood. Finally, we examined the relation of child variables (attachment classification, temperament rating and observed behaviours) to the parents' ratings of pleasure in the child.     

视觉追踪作业心理负荷的多变量评估研究

敏感性是心理负荷测量技术可靠性的基本要求。该研究利用主任务绩效、次任务绩效、主观“加权负荷”评定和心率变异变化率四项指标,在计算机模拟情境下对视觉追踪作业心理负荷进行多变量评估实验。结果发现,以上述四项指标为基础建立的“综合加权评估指数”是一项较有效的评估指标,其敏感性远高于任何单独的评定。     

The influence of parent-child relationship on young adolescents' use of safety equipment. The Norwegian Longitudinal Health Behavior Study

The purpose of this longitudinal study was to examine the extent to which the parent-child relationship, as perceived by young adolescents at age 13, may account for the use of various types of safety equipment at age 13 and 14 in terms of seat belts, bicycle helmets, motorcycle helmets when passenger, reflectors on the clothing when outside in the dark, and lifejackets when on board small boats. Parental influence was assessed in terms of three scales: Parental support, parental monitoring of the youngsters, and opposition towards the parents, with satisfactory internal consistencies (alphas >0.78). The results showed that each of the three constructs significantly accounted for an independent portion of the variance in the use of safety equipment measures. In sum they accounted for 20% of the variance in the use of safety equipment at age 13, and about 10% at age 14. The findings are discussed with regard to the implications for accident prevention measures aimed at young people.     

Delayed matching-to-sample performance: Effects of relative reinforcer frequency and of signaled versus unsignaled reinforcer magnitudes

Six pigeons were trained on a delayed red-green matching-to-sample task that arranged four delays within sessions. Matching responses intermittently produced either 1.5-s access to food or 4.5-s access to food, and nonmatching responses produced either 1.5-s or 4.5-s blackout. Two phases were conducted: a signaled phase in which the reinforcer magnitudes (small and large) were signaled by houselights (positioned either on the left or right of the chamber), and an unsignaled phase in which there was no correlation between reinforcer magnitude and houselight position. In both phases, the relative frequency with which red and green matching responses produced food was varied across five values. Both matching accuracy and the sensitivity of performance to the distribution of reinforcers for matching responses decreased with increasing delays in both phases. In addition, accuracy and reinforcer sensitivity were significantly lower on signaled small-reinforcer trials compared with accuracy and sensitivity values on signaled large-reinforcer trials and on both types of unsignaled trials. These results are discussed in the context of research on both nonhuman animal and human memory.     

Sensitivity analysis in factor analysis: Difference between using covariance and correlation matrices

Influence curves of some parameters under various methods of factor analysis have been given in the literature. These influence curves depend on the influence curves for either the covariance or the correlation matrix used in the analysis. The differences between the influence curves based on the covariance and the correlation matrices are derived in this paper. Simple formulas for the differences of the influence curves, based on the two matrices, for the unique variance matrix, factor loadings and some other parameter are obtained under scale-invariant estimation methods, though the influence curves themselves are in complex forms.The authors are most grateful to the referees, the Associate Editor, the Editor and Raymond Lam for helpful suggestions for improving the clarity of the paper.     

Assessing local influence for specific restricted likelihood: Application to factor analysis

In restricted statistical models, since the first derivatives of the likelihood displacement are often nonzero, the commonly adopted formulation for local influence analysis is not appropriate. However, there are two kinds of model restrictions in which the first derivatives of the likelihood displacement are still zero. General formulas for assessing local influence under these restrictions are derived and applied to factor analysis as the usually used restriction in factor analysis satisfies the conditions. Various influence schemes are introduced and a comparison to the influence function approach is discussed. It is also shown that local influence for factor analysis is invariant to the scale of the data and is independent of the rotation of the factor loadings. The authors are most grateful to the referees, the Associate Editor, and the Editor for helpful suggestions for improving the clarity of the paper.     

Resistance to change and the law of effect

Three experiments using multiple schedules of reinforcement explored the implications of resistance-to-change findings for the response-reinforcer relation described by the law of effect, using both steady-state responding and responding recorded in the first few sessions of conditions. In Experiment 1, when response-independent reinforcement was increased during a third component, response rate in Components 1 and 2 decreased. This response-rate reduction was proportionately greater in a component in which reinforcer magnitude was small (2-s access to wheat) than in the component in which it was large (6-s access to wheat). However, when reinforcer rates in the two components were varied together in Experiments 2 and 3, response-rate change was the same regardless of the magnitude of reinforcers used in the two components, so that sensitivity of response rates to reinforcer rates (Experiment 2) and of response-rate ratios to reinforcer-rate ratios (Experiment 3) was unaffected by the magnitude of the reinforcers. Therefore, the principles determining resistance to change, described by behavioral momentum theory, seem not to apply when the source of behavior change is the variation of reinforcement contingencies that maintain the behavior. The use of extinction as a manipulation to study resistance to change is questioned.     

年老过程认知作业完成量与作业速度相互关系的研究

本工作应用自行设计的计算机逐级限速程序,研究了年老过程四项认知作业完成量与作业速度的相互关系。被试350人,46—75岁。研究结果表明:1、随着计算机所限时间的缩短,各项作业完成量均随年老下降迅速,作业完成量对于作业速度的依存关系随年老表现极为明显;2、在逐级限速条件下,四项认知作业完成量的年老敏感性顺序与作业速度的年老敏感性顺序基本相同,即是:符号数字、心算、计数和数字鉴别。