A diffusion model analysis of the effects of aging on brightness discrimination

The effects of aging on decision time were examined in a brightness discrimination experiment with young and older subjects (ages, 60-75 years). Results showed that older subjects were slightly slower than young subjects but just as accurate. Ratcliff's (1978) diffusion model was fit to the data, and it provided a good account of response times, their distributions, and response accuracy. There was a 50-msec slowing of the nondecision components of response time for older subjects relative to young subjects, but response criteria settings and rates of accumulation of evidence from stimuli were roughly equal for the two groups. These results are contrasted with those obtained from letter discrimination and signal-detection-like tasks.     

Binocular processing of brightness information: a vector-sum model

The relation between monocular and binocular brightness was examined. Clear evidence was found that the interaction between visual channels in binocular processing of brightness information implicates both an apparent averaging of monocular brightness when they are grossly different and a partial summation when they approach equality. A vector-sum model is shown to predict these properties. A nonmetric method was used to fit such a model to data from three experiments in each of which 15 subjects estimated brightness of binocularly fused targets. Magnitude estimation was used in two experiments, and cateogry ratings were obtained in the third experiment. When it was assumed only that subjects' responses were monotone with perceived brightness, estimates of the model's parameters from the data of the three experiments were almost identical, indicating that results from magnitude estimati;n and category rating can converge once nonlinear response functions are eliminated.     

动态性对简笔画动物审美的影响及其神经机制

运用行为和fMRI技术, 通过比较动态刺激与静态刺激审美判断的行为和脑机制的异同探讨动态性对简笔画动物审美的影响, 包括两个实验。结果发现, 动态简笔画动物的美观程度评分和喜欢程度评分都显著高于静态简笔画动物。同时, 动态简笔画动物审美判断激活的区域基本涵盖了静态简笔画动物审美所激活的区域, 二者都激活了枕叶区等视觉加工区域、额叶区等认知加工区域、眶额叶皮层等奖赏区域以及海马、脑岛、扣带回、杏仁核等情绪加工区域。与静态简笔画动物的审美相比, 动态简笔画动物的审美显著激活了双侧舌回、双侧MT。本研究结果表明, 动态性影响了对简笔画动物的审美, 动态简笔画动物比静态简笔画动物被判断为更加美观。     

A dynamic generalization of the Rasch model

In the present paper a model for describing dynamic processes is constructed by combining the common Rasch model with the concept of structurally incomplete designs. This is accomplished by mapping each item on a collection of virtual items, one of which is assumed to be presented to the respondent dependent on the preceding responses and/or the feedback obtained. It is shown that, in the case of subject control, no unique conditional maximum likelihood (CML) estimates exist, whereas marginal maximum likelihood (MML) proves a suitable estimation procedure. A hierarchical family of dynamic models is presented, and it is shown how to test special cases against more general ones. Furthermore, it is shown that the model presented is a generalization of a class of mathematical learning models, known as Luce's beta-model.     

A dynamic factor model for the analysis of multivariate time series

As a method to ascertain the structure of intra-individual variation,P-technique has met difficulties in the handling of a lagged covariance structure. A new statistical technique, coined dynamic factor analysis, is proposed, which accounts for the entire lagged covariance function of an arbitrary second order stationary time series. Moreover, dynamic factor analysis is shown to be applicable to a relatively short stretch of observations and therefore is considered worthwhile for psychological research. At several places the argumentation is clarified through the use of examples.I would like to thank WM. van der Molen, G. J. Mellenbergh and L. H. M. Oppenheimer, who provided valuable ideas that led to this formulation.     

Brief dynamic group therapy: A psychoeducational model for enhancing caregiver-infant development

A group model for providing short-term caregiver-infant psychoeducation is presented. The goal of this model is to modify over a brief and circumscribed period of time the perceptions and expectations of caregivers so that their interpersonal behaviors with their infants sustain and enhance adaptive interactive sequences. This model of intervention is derived from the intuitive behavior patterns of adaptive caregivers concerning the infant's emerging representational abilities. Specific vignettes exemplifying the stages of group development that occur with this model of intervention are discussed.     

A dynamic model of loudness adaptation

Previous research on loudness adaptation has provided heterogeneous and partly contradictory results. One major reason seems to be the inconsistent use of the term 'adaptation', which is due to differing operational definitions. Here, a measurement-theoretic definition of loudness adaptation is introduced, which also comprises a new method for the identification of certain linear dynamic systems. This is of particular interest, since there is a lack of dynamic models describing loudness adaptation. An experiment with sinusoidal sound stimuli (3000 Hz) was performed to test whether loudness adaptation can be modeled by such a linear system. The results of the system identification indicate that this is possible. Therefore, it can be concluded that the given definition of loudness adaptation might be appropriate and that the method of system identification is an applicable research tool.     

A dynamic model of guilt: implications for motivation and self-regulation in the context of prejudice

Guilt is widely recognized as an important self-regulatory emotion, yet alternative theoretical accounts view guilt primarily as either a punishment cue or a prosocial motivator. Integrating these views, we propose that guilt functions dynamically to first provide a negative reinforcement cue associated with reduced approach motivation, which transforms into approach-motivated behavior when an opportunity for reparation presents itself. We tested this hypothesis in the context of racial prejudice. White subjects viewed a multiracial series of faces while cortical activity was recorded using electroencephalography. Following bogus feedback indicating anti-Black responses, subjects reported elevated guilt, which was associated with changes in frontal cortical asymmetry indicating reduced approach motivation. When subjects were presented with an opportunity to engage in prejudice-reducing behavior, guilt predicted greater interest in prejudice reduction, which in turn was associated with an approach-related shift in frontal asymmetry. The results support a dynamic model in which guilt is associated with adaptive changes in motivation and behavior.     

Visual discrimination of shape by Humans. II: (I) matrix figures and (II) minimal area changes

Two experiments are described in which an attempt was made systematically to vary two dimensional shapes according to a pre-arranged design. In the first, subjects were presented tachistoscopically with pairs of “reflexive matrix figures” whose members were either horizontally or vertically orientated; and it was found that reaction times to horizontal pairs were faster than to vertical ones, a result that is in keeping with previous findings. In the second experiment two ensembles were devised that were alike in every respect save that one group was extended or reduced vertically while the other varied horizontally. Performance was better on the vertically orientated ensemble. These findings are briefly related to former studies and the pre-eminence of vertical symmetry is underlined.     

A dynamic context model of interactive behavior

A dynamic context model of interactive behavior was developed to explain results from two experiments that tested the effects of interaction costs on encoding strategies, cognitive representations, and response selection processes in a decision-making and a judgment task. The model assumes that the dynamic context defined by the mixes of internal and external representations and processes are sensitive to the interaction cost imposed by the task environment. The model predicts that changes in the dynamic context may lead to systematic biases in cognitive representations and processes that eventually influence decision-making and judgment outcomes. Consistent with the predictions by the model, results from the experiments showed that as interaction costs increased, encoding strategies and cognitive representations shifted from perception-based to memory-based. Memory-based comparisons of the stimuli enhanced the similarity and dominance effects, and led to stronger systematic biases in response outcomes in a choice task. However, in a judgment task, memory-based representations enhanced only the dominance effects. Results suggested that systematic response biases in the dominance context were caused by biases in the cognitive representations of the stimuli, but response biases in the similarity context were caused by biases in the comparison process induced by the choice task. Results suggest that changes in interaction costs not only change whether information was assessed from the external world or from memory but also introduce systematic biases in the cognitive representation of the information, which act as biased inputs to the subsequent decision-making and judgment processes. Results are consistent with the idea of interactive cognition, which proposes that representations and processes are contingent on the dynamic context defined by the information flow between the external task environment and internal cognition.     

A dynamic stimulus-driven model of signal detection

Signal detection theory forms the core of many current models of cognition, including memory, choice, and categorization. However, the classic signal detection model presumes the a priori existence of fixed stimulus representations--usually Gaussian distributions--even when the observer has no experience with the task. Furthermore, the classic signal detection model requires the observer to place a response criterion along the axis of stimulus strength, and without theoretical elaboration, this criterion is fixed and independent of the observer's experience. We present a dynamic, adaptive model that addresses these 2 long-standing issues. Our model describes how the stimulus representation can develop from a rough subjective prior and thereby explains changes in signal detection performance over time. The model structure also provides a basis for the signal detection decision that does not require the placement of a criterion along the axis of stimulus strength. We present simulations of the model to examine its behavior and several experiments that provide data to test the model. We also fit the model to recognition memory data and discuss the role that feedback plays in establishing stimulus representations.     

A model for mastery learning based on dynamic equilibrium theory

A theoretical model is developed based on dynamic equilibrium theory, which suggests a quantitative explanation for the basic idea in mastery learning that individuals of different aptitude reacting in an ideal environment to the same total quantity of material will ultimately reach the same mastery status, or gain equal increments of status starting from the same base, in time spans inversely proportional to the aptitude. The approach incorporates two widely used mechanisms, one for growth in learning and intelligence and one for loss through forgetting, into a single model that treats acquisition and loss as opposing, but simultaneously occuring processes. Operational definitions for acquisition and loss rate constants that would enable the model to account exactly for the basic assumption of mastery learning and at the same time yield a growth pattern identical to that implicit in the Stanford Binet ratio IQ are identified. An analysis of the extent to which the requirements of the model are confirmed by the available experimental evidence reveals that the basic idea of mastery learning is a useful and convenient approximation, which applies with some validity to the growth of mental ability as well as to the growth in school achievement.     

The shape of ears to come: dynamic coding of auditory space

In order to pinpoint the location of a sound source, we make use of a variety of spatial cues that arise from the direction-dependent manner in which sounds interact with the head, torso and external ears. Accurate sound localization relies on the neural discrimination of tiny differences in the values of these cues and requires that the brain circuits involved be calibrated to the cues experienced by each individual. There is growing evidence that the capacity for recalibrating auditory localization continues well into adult life. Many details of how the brain represents auditory space and of how those representations are shaped by learning and experience remain elusive. However, it is becoming increasingly clear that the task of processing auditory spatial information is distributed over different regions of the brain, some working hierarchically, others independently and in parallel, and each apparently using different strategies for encoding sound source location.