Behavioral momentum in computer-presented discriminations in individuals with severe mental retardation

Behavioral momentum was examined in 2 individuals with severe mental retardation via within-subject manipulations of obtained reinforcer rates. Subjects performed self-paced discrimination problems presented on a touch screen computer monitor. Two different problems, Tasks A and B, alternated in blocks of 15 trials on a multiple schedule. Reinforcers were snack foods. The reinforcement schedule for Task A was continuous (fixed-ratio 1) and the schedule for Task B was continuous in some conditions and variable ratio in other conditions. Behavioral momentum was assessed in test sessions by prefeeding, presenting response-independent food, and making available alternatives to the tasks. When the obtained reinforcer rate for Task A was at least twice that for Task B, resistance to change was greater for Task A. When both reinforcer rates and response rates were a pproximately equal for the two tasks, resistance to change was approximately equal. These results are consistent with behavioral momentum effects. They extend previous findings with humans by examining momentum in self-initiated discrete-trial discrimination tasks with ratio schedules, and by isolating relative reinforcer rates as a controlling variable via within-subject manipulations.     

Generative models, brain function and neuroimaging

The representational capacity and inherent function of any neuron, neuronal population or cortical area in the brain is dynamic and context-sensitive. Functional integration, or interactions among brain systems, that employ driving (bottom up) and backward (top-down) connections, mediate this adaptive and contextual specialisation. A critical consequence is that neuronal responses, in any given cortical area, can represent different things at different times. This can have fundamental implications for the design of brain imaging experiments and the interpretation of their results. Our arguments are developed under generative models of brain function, where higher-level systems provide a prediction of the inputs to lower-level regions. Conflict between the two is resolved by changes in the higher-level representations, which are driven by the ensuing error in lower regions, until the mismatch is "cancelled". From this perspective the specialisation of any region is determined both by bottom-up driving inputs and by top-down predictions. Specialisation is therefore not an intrinsic property of any region but depends on both forward and backward connections with other areas. Because the latter have access to the context in which the inputs are generated they are in a position to modulate the selectivity or specialisation of lower areas. The implications for classical models (e.g., classical receptive fields in electrophysiology, classical specialisation in neuroimaging and connectionism in cognitive models) are severe and suggest these models may provide incomplete accounts of real brain architectures. Here we focus on the implications for cognitive neuroscience in the context of neuroimaging.     

Rotation in the dynamic factor modeling of multivariate stationary time series

A special rotation procedure is proposed for the exploratory dynamic factor model for stationary multivariate time series. The rotation procedure applies separately to each univariate component series of aq-variate latent factor series and transforms such a component, initially represented as white noise, into a univariate moving-average. This is accomplished by minimizing a so-called state-space criterion that penalizes deviations of the rotated solution from a generalized state-space model with only instantaneous factor loadings. Alternative criteria are discussed in the closing section. The results of an empirical application are presented in some detail.This research was supported by the Institute for Developmental and Health Research Methodology, University of Virginia.     

Is touch a valid therapeutic intervention? Early returns from a qualitative study of therapists' views

Findings are reported from six semi‐structured interviews with experienced psychotherapists, focusing on the reasons for using touch and the sort of touch used. They suggest that there is a distinction being made by therapists between ‘social space’ and ‘therapeutic space’, and a different view of touch taken if it is judged by the therapist to be ‘out of the therapeutic environment’. Whether or not touch was initiated by the therapist or the client would also appear to influence its further discussion by the therapist, either in processing it with the client or in supervision. What also emerged from the interviews was the finding that an exploration of touch in supervision was unusual. The implications for practice, supervision and training are discussed as areas for further exploration in the main survey, which will be conducted in the second year of the research.     

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.     

A Semantics for Means-end Relations

There has been considerable work on practical reasoning in artificial intelligence and also in philosophy. Typically, such reasoning includes premises regarding means–end relations. A clear semantics for such relations is needed in order to evaluate proposed syllogisms. In this paper, we provide a formal semantics for means–end relations, in particular for necessary and sufficient means–end relations. Our semantics includes a non-monotonic conditional operator, so that related practical reasoning is naturally defeasible. This work is primarily an exercise in conceptual analysis, aimed at clarifying and eventually evaluating existing theories of practical reasoning (pending a similar analysis regarding desires, intentions and other relevant concepts). “They were in conversation without speaking. They didn’t need to speak. They just changed reality so that they had spoken.” Terry Pratchett, Reaper Man     

动态视觉加工与儿童汉字阅读

使用视觉阈限测验、图片命名、字形相似性判断实验和语音意识等测验 ,考察了小学五年级儿童视觉加工技能与汉字阅读之间的关系。结果发现 :动态视觉加工与图片命名错误率、字形判断反应时和错误率、语音意识均有显著相关 ,静态视觉加工只与图片命名错误率相关显著 ;控制识字量后的偏相关分析显示 ,动态视觉加工与其他变量的相关关系不变 ,静态视觉加工与图片命名错误率的相关不再显著 ;回归分析发现动态视觉加工在识字量和语音意识的影响控制后 ,能够分别解释阅读流畅性、字形判断反应时和图片命名错误率 7%、2 5 %和 5 6 %的变化 ;语音意识能够解释识字量和阅读流畅性 9%和 10 %的变化 ;对差读者的动态视觉加工和语音意识分析发现 ,儿童在这两种测验上的个体差异很大。上述结果表明 ,阅读过程受基本知觉技能影响 ,动态视觉加工作用于汉字阅读的特定过程。     

新员工心理契约短期动态变化的实证研究

本文从心理契约具有动态性的角度出发,考察了新员工进入企业组织后的社会化过程中,心理契约预期、心理契约执行与心理契约违背三方面的变化。样本为382名进入企业组织的一年半以内的新员工。结果验证,心理契约在我国具有不同程度的短期动态变化的特性,具体情况因心理契约的预期、执行和违背的各维度而有所不同。同时,新员工早期工作经验与心理契约执行中的交易性义务变化有显著性差异。