Global and local covert visual attention: Evidence from a bayesian hidden markov model

Psychological, psychophysical and physiological research indicates that people switch between two covert attention states, local and global attention, while visually exploring complex scenes. The focus in the local attention state is on specific aspects and details of the scene, and on examining its content with greater visual detail. The focus in the global attention state is on exploring the informative and perceptually salient areas of the scene, and possibly on integrating the information contained therein. The existence of these two visual attention states, their relative prevalence and sequence in time has remained empirically untested to date. To fill this gap, we develop a psychometric model of visual covert attention that extends recent work on hidden Markov models, and we test it using eye-movement data. The model aims to describe the observed time series of saccades typically collected in eye-movement research by assuming a latent Markov process, indicative of the brain switching between global and local covert attention. We allow subjects to be in either state while exploring a stimulus visually, and to switch between them an arbitrary number of times. We relax the no-memory-property of the Markov chain. The model that we develop is estimated with MCMC methodology and calibrated on eye-movement data collected in a study of consumers' attention to print advertisements in magazines.We thank Dominique Claessens of Verify International for making the data available to us.     

Tucker3 hierarchical classes analysis

This paper presents a new model for binary three-way three-mode data, called Tucker3 hierarchical classes model (Tucker3-HICLAS). This new model generalizes Leenen, Van Mechelen, De Boeck, and Rosenberg's (1999) individual differences hierarchical classes model (INDCLAS). Like the INDCLAS model, the Tucker3-HICLAS model includes a hierarchical classification of the elements of each mode, and a linking structure among the three hierarchies. Unlike INDCLAS, Tucker3-HICLAS (a) does not restrict the hierarchical classifications of the three modes to have the same rank, and (b) allows for more complex linking structures among the three hierarchies. An algorithm to fit the Tucker3-HICLAS model is described and evaluated in an extensive simulation study. An application of the model to hostility data is discussed.The first author is a Research Assistant of the Fund for Scientific Research-Flanders (Belgium). The research reported in this paper was partially supported by the Research Council of K.U. Leuven (GOA/2000/02). We are grateful to Kristof Vansteelandt for providing us with an interesting data set.     

Inductive reasoning and judgment interference: experiments on Simpson's paradox

In a series of experiments on inductive reasoning, participants assessed the relationship between gender, success, and a covariate in a situation akin to Simpson's paradox: Although women were less successful then men according to overall statistics, they actually fared better then men at either of two universities. Understanding trivariate relationships of this kind requires cognitive routines similar to analysis of covariance. Across the first five experiments, however, participants generalized the disadvantage of women at the aggregate level to judgments referring to the different levels of the covariate, even when motivation was high and appropriate mental models were activated. The remaining three experiments demonstrated that Simpson's paradox could be mastered when the salience of the covariate was increased and when the salience of gender was decreased by the inclusion of temporal cues that disambiguate the causal status of the covariate.     

Preservation of autobiographical memory in a case of pure progressive amnesia

G.D., a 79 year-old female, presents with a severe and slowly progressive amnesia although she remains entirely independent in daily life and is perfectly well spatially oriented. Her amnesia is relatively isolated and her deficit does not embrace other cognitive domains. G.D. underwent extensive neuropsychological evaluation including language, executive functions, perceptual, and memory tests. Based on clinical observation, the purpose of this study was to determine whether there was a dissociation between her autobiographical and semantic memory. Results point out a severely degraded semantic knowledge of famous public events and persons while autobiographical memory of personally experienced and relevant information remains intact. Results from this study and from previous studies seem to suggest that relative sparing of hippocampal structures may be related to the preservation of autobiographical memory.     

Mental pain and its relationship to suicidality and life meaning

Shneidman (1996) proposed that intense mental pain is related to suicide. Relatedly, Frankl (1963) argued that the loss of life's meaning is related to intense mental pain. The first goal of this research was to test Shneidman's proposition by comparing the mental pain of suicidal and nonsuicidal individuals. Meaning in life and optimism are the polar opposites of suicidality and hopelessness, and the examination of these variables in relation to mental pain was undertaken to provide a test of Frankl's proposition. In two studies, a relationship between a newly developed measure of mental pain--the Orbach & Mikulincer Mental Pain Scale, 2002 (OMMP; see also Orbach, Mikulincer, Sirota & Gilboa-Schechtman, 2002)--and suicidal behavior and life meaning were examined. Results confirmed both propositions. Implications for the study of mental pain and suicide are discussed.     

Terminal decline and cognitive performance in very old age: does cause of death matter?

Cross-sectional differences and longitudinal changes in cognitive functioning in relation to mortality across a 7-year follow-up period, with 3 times of measurement, were examined in a population-based sample of very old adults. The authors also sought to determine whether cause of death (cerebro/cardiovascular disease [CVD]; non-CVD) modified the magnitude of mortality-related cognitive deficits. Cognitive performance was indexed by tests of general cognitive ability, episodic memory, primary memory, verbal fluency, and visuospatial ability. Results indicated cross-sectional differences on all domains of functioning, with persons who would die within 3 years after baseline testing performing more poorly. Longitudinally, greater decrements were observed on all domains for persons who would die after the first follow-up period, as compared with survivors. Cause of death failed to modify the magnitude of the cross-sectional and longitudinal deficits. The pattern of results point to the general nature of this phenomenon.     

Differential effects of aging on processes involved in mental imagery generation]

The purpose of this study was to measure the degree to which the deterioration of mental image generation processes observed in elderly subjects by Dror and Kosslyn (1994) depends on the nature of the processing (referential vs. representational) involved in performing the task at hand. In keeping with the results of research showing that processing resources diminish as normal aging occurs (Craik & Bird, 1982; Rabinowitz, Craik & Ackerman, 1982), we suggest that generation ability based on referential processing is affected to a greater extent in older adults than is the generation ability involving representational processing. Fifteen young adults and 15 elderly persons performed a generation task modeled on that used by Dror and Kosslyn (1994). Observations were based on two contrasting conditions. In the first instance, subjects were required to generate an image representation of numbers when instructed to do so by a graphic stimulus, e.g., "31" (representational generation). In the second case, generation was produced on the basis of a verbal stimulus, e.g., "thirteen" (referential generation). Results (response time and number of accurate answers) show that, compared to young adults, elderly adults have a diminished ability to generate images based on words rather than numbers and do so at a slower pace. Our results suggest, therefore, that the performance of the first type of generation is cognitively more demanding for elderly subjects than that which is founded on figurative stimuli. The deterioration of mental image generation processes observed in elderly subjects by Dror and Kosslyn (1994) is therefore dependent on the nature of processing (referential vs. In conclusion we suggest two complementary assumptions to explain the observed dissociation. The differential effect of age may be the result of a deficienness cy linked to the nature of processing (control vs. automatic). Our second assumption is that, more specifically, referential generation involves more processing resources than does representational generation because it requires an additional transcoding operation. In this instance, the differential effect of aging that we observed would be closely linked to the number of cognitive operations involved in mental image generation.     

Beyond the Obvious: Chronic Vividness of Imagery and the Use of Information in Decision Making

The authors investigate two competing hypotheses about how chronic vividness of imagery interacts with the vividness and salience of information in decision making. Results from four studies, covering a variety of decision domains, indicate that chronic imagery vividness rarely amplifies the effects of vivid and salient information. Imagery vividness may, in fact, attenuate the effects of vivid and salient information. This is because, relative to nonvivid imagers, vivid imagers rely less on information that appears obvious and rely more on information that seems less obvious. This tendency is so robust that vividness of imagery may amplify the effects of vivid information only when this information is the only information available in the decision field. The findings seem to reflect vivid imagers' tendency to totally immerse themselves in a decision problem and scrutinize the available information creatively.     

Influence of Expertise on the Intentional Transfer of Motor Skill

Intentional transfer of expert knowledge is an important issue in cognitive science and motor skills. How subjects deliberately transfer expertise in karate when learning a closely related motor skill (tai chi) was examined in this study. Subjects (N = 20) learned a videotaped sequence of self-defense movements, evaluated their learning, and then performed the sequence. Self-regulation of learning is believed to be central to effective transfer. The measures of self-regulation were accuracy of self-evaluation, video use, and approach to learning. Results showed that unlike novices, experts used self-regulation, learning strategies, and the video player in more complex ways in self-regulation. Experts, as compared with novices, demonstrated their greater knowledge through the higher quality of their performance and their better comprehension of movement meaning; but both groups recalled an equal number of moments, suggesting that both experts and novices transferred general knowledge about learning.     

Faulty Judgment,Expert Opinion,and Decision-Making Capacity

An assessment of decision-making capacity is the accepted procedure for determining when a person is not competent. An inferential gap exists between the criteria for capacity specific abilities and the legal requirements to understand relevant information and appreciate the consequences of a decision. This gap extends to causal influences on a person'scapacity to decide. Using a published case of depression, we illustrate that assessors' uses of diagnostic information is frequently not up to the task of bridging this inferential gap in a justifiable way. We then describe cases of faulty judgement which challenge the understanding of diagnostic causal influences. These cases help to clarify the nature of the expertise required for capacity assessments. In practice, the requirements of decision-making capacity are often abandoned to other considerations due to a lack of requisite expertise. The legal policy supporting decision-making capacity as a means to protective intervention is justified only if the requisite expertise is developed. We propose the requisite expertise to be developed in the long term as a distinct multidisciplinary endeavour.