Nonlinearity in the Epidemiology of Complex Health and Disease Processes

Theoretical Medicine and Bioethics - The challenges posed by chronic illness have pointed out to epidemiologists the multifactorial complex nature of disease causality. This notion has been...     

The impact of task complexity on information use in multi-attribute decision making

This study presents a process analysis of multi-attribute decision making. The decision problems concerned the selection of the most suitable candidate for a job opening. The problems varied in terms of complexity, i.e. the number of candidates and the number of attributes used to describe these alternatives. Results show that with an increasing number of alternatives, subjects (N = 48) used fewer attributes for the evaluation of alternatives, and made, on average, less references to the alternatives. The type of judgment most often used was absolute dimensional (comparison of an attribute to an absolute standard) and was used more often at the beginning than toward the end of the decision process. Overall, judgments were predominantly positive. The percentage of positive judgments decreased with increasing complexity, and toward the end of the decision process. Significantly more judgments, particularly positive ones, concerned the finally chosen alternative as compared to the rest of the alternatives. Finally, analysis of subjects' usage of decision rules revealed that increasing the number of alternatives resulted in an increasing use of elimination strategies. Implications of these findings for the design of decision aids will be discussed.     

Aggressive and affiliative behavior in green monkeys with differing housing complexity

Eleven green monkeys (Cercopithecus aethiops) were combined into three social groups (two heterosexual, one all-male) in enclosures with similar volume but different levels of environmental complexity (two or four compartments). Agonistic and affiliative interactions were recorded over a 21-week period. The two heterosexual groups had their environmental complexity reduced (number of compartments reduced by one-half and volume/floorspace reduced by one-third) for a 5-week period in the middle of the study. Rates of contact aggression were low throughout the study. In the group with complexity reduced to one compartment, rates of noncontact aggression and affiliative behavior increased, and remained high after complexity was restored. In the group reduced to two compartments, rates of affiliative behavior increased but rates of noncontact aggression decreased, trends which continued after complexity was restored. The all-male group exhibited low rates of affiliative behavior throughout. Two compartments appear to foster successful group formation, but any change in a group's enclosure can have long-term effects on rates of aggression. © 1992 Wiley-Liss, Inc.     

Young children combine sensory cues with learned information in a statistically efficient manner: But task complexity matters

Human adults are adept at mitigating the influence of sensory uncertainty on task performance by integrating sensory cues with learned prior information, in a Bayes‐optimal fashion. Previous research has shown that young children and infants are sensitive to environmental regularities, and that the ability to learn and use such regularities is involved in the development of several cognitive abilities. However, it has also been reported that children younger than 8 do not combine simultaneously available sensory cues in a Bayes‐optimal fashion. Thus, it remains unclear whether, and by what age, children can combine sensory cues with learned regularities in an adult manner. Here, we examine the performance of 6‐ to 7‐year‐old children when tasked with localizing a ‘hidden’ target by combining uncertain sensory information with prior information learned over repeated exposure to the task. We demonstrate that 6‐ to 7‐year‐olds learn task‐relevant statistics at a rate on par with adults, and like adults, are capable of integrating learned regularities with sensory information in a statistically efficient manner. We also show that variables such as task complexity can influence young children's behavior to a greater extent than that of adults, leading their behavior to look sub‐optimal. Our findings have important implications for how we should interpret failures in young children's ability to carry out sophisticated computations. These ‘failures’ need not be attributed to deficits in the fundamental computational capacity available to children early in development, but rather to ancillary immaturities in general cognitive abilities that mask the operation of these computations in specific situations.     

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.     

Semantic weight and verb retrieval in aphasia

Individuals with agrammatic aphasia may have difficulty with verb production in comparison to nouns. Additionally, they may have greater difficulty producing verbs that have fewer semantic components (i.e., are semantically "light") compared to verbs that have greater semantic weight. A connectionist verb-production model proposed by Gordon and Dell (2003) learns through error correction to "divide the labor" between syntax and semantics. Verbs that are semantically heavier come to depend less on syntax and more on semantics. For lighter verbs, the reverse is true. We performed this study to clarify the role of semantic weight in aphasic verb production and to test the prediction from Gordon and Dell that a brain lesion that impairs the syntactic input to verb retrieval will impair lighter verbs more than heavier ones. Consistent with this prediction, we found that the decrement for lighter verbs was present in a group with agrammatic aphasia but not in a matched group without agrammatism.     

Principle of organization: a dynamic-systems view of the archetype-as-such

The personality is a dynamic system. Like all other dynamic systems, it must be self-organized. In this paper I focus upon the archetype-as-such, that is, upon the essential core around which both an archetypical image and a complex are organized. I argue that an archetype-as-such is a pre-existing principle of organization. Within the personality that principle manifests itself as a psychological vortex (a complex) into which we are drawn. The vortex is impersonal. We mediate it through myths and rituals or through consciousness. In this paper I show that Jung's intuition about the archetype-as-such is supported by recent science. I evaluate other concepts of the archetype. My concept is different from that proposed recently by Saunders and Skar. My concept allows each archetype-as-such to be defined precisely in mathematical terms. It suggests a new interpretation of mythology. It also addresses our spiritual experience of an archetype. Because the archetypes-as-such are fundamental to the personality, the better we understand them the better we understand our patients. The paper is grounded with clinical examples.     

决策者的认知特征对决策过程及企业战略选择的影响

在不确定环境下,企业的最高决策者的个人特性和行为对于企业的战略决策起着关键的作用。本研究探讨决策者的认知特征对于战略决策的过程以及最终形成的战略决策的影响。研究采用情境实验法,根据某企业的实际情形编写了一个商业案例,案例提供了决策者所需要的信息,并制造出高不确定的情境。148名来自大学管理学院的学生被要求对于该案例进行分析并填写有关量表。对数据进行结构方程模型的分析后得到如下结果：决策者的认知复杂性和认知需要与他们对企业内外环境的周密分析具有显著的正向关系,而且通过后者影响到对于环境中蕴含的机会的判断,并最终影响是否进入某项业务的决策。     

笔画复杂性和重复性对笔画和汉字认知的影响

采用笔画识别和词汇决定的方法 ,对汉字笔画认知和笔画在汉字认知中的作用作了考察。实验一探讨了汉字笔画自身的复杂性对笔画认知的影响。结果表明 ,笔画自身的复杂性对笔画认知无显著影响 ,识别简单笔画和识别复杂笔画的反应时与错误率无显著差异。实验二考察了笔画的重复性对汉字认知的影响。结果表明 ,汉字认知中存在笔画重复性效应。笔画重复较多的汉字比笔画较少重复的汉字识别时间短 ,错误率亦低。整个实验结果支持笔画是汉字加工的基本单元的假设