Toward the neural basis of verbal priming: A cognitive-neuropsychological synthesis

Repetition priming is a mnemonic phenomenon that has attracted considerable attention from neuropsychologists and cognitive scientists. In an attempt at elucidating the putative mechanisms of priming, the present review draws on evidence from both domains. The review is restricted to verbal priming of visually presented stimuli—an area that accounts for the majority of empirical studies of priming. A number of theoretical accounts are presented. The interim conclusion is that neither multiple systems nor unitary system-multiple process theories can adequately explain the data on priming, although both contain many valid components. An integrative model is proposed to improve the explanation of the empirical evidence. The central assertion of the proposed model is that repetition priming depends on perceptual processes that can be mapped on specific neural systems. It is postulated that individual differences in perceptual processing ability predict variability in memory performance. It is proposed that data-driven priming of verbal stimuli critically depends on the activity of primary and secondary visual cortices in the right hemisphere, whereas conceptually-driven priming is hypothesized to rely on the activities of higher order tertiary association cortices in language areas and more anterior neocortical areas.     

Posthypnotic suggestion and the modulation of Stroop interference under cycloplegia

Recent data indicate that under a specific posthypnotic suggestion to circumvent reading, highly suggestible subjects successfully eliminated the Stroop interference effect. The present study examined whether an optical explanation (e.g., visual blurring or looking away) could account for this finding. Using cyclopentolate hydrochloride eye drops to pharmacologically prevent visual accommodation in all subjects, behavioral Stroop data were collected from six highly hypnotizables and six less suggestibles using an optical setup that guaranteed either sharply focused or blurred vision. The highly suggestibles performed the Stroop task when naturally vigilant, under posthypnotic suggestion not to read, and while visually blurred; the less suggestibles ran naturally vigilant, while looking away, and while visually blurred. Although visual accommodation was precluded for all subjects, posthypnotic suggestion effectively eliminated Stroop interference and was comparable to looking away in controls. These data strengthen the view that Stroop interference is neither robust nor inevitable and support the hypothesis that posthypnotic suggestion may exert a top-down influence on neural processing.     

Explaining Normativity: On Rationality and the Justification of Reason

Aspects of the world are normative in as much as they or their existence constitute reasons for persons, i.e. grounds which make certain beliefs, moods, emotions, intentions or actions appropriate or inappropriate. Our capacities to perceive and understand how things are, and what response is appropriate to them, and our ability to respond appropriately, make us into persons, i.e. creatures with the ability to direct their own life in accordance with their appreciation of themselves and their environment, and of the reasons with which, given how they are, the world presents them.
An explanation of normativity would explain the various puzzling aspects of this complex phenomenon. In particular it would explain how it is that aspects of the world can constitute reasons for cognitive, emotive, and volitional responses; how it is that we can come to realise that certain cognitive, emotional or volitional responses are appropriate in various circumstances, and inappropriate in others; and how it is that we can respond appropriately. This paper explores an aspect of the last of these questions.     

Age-related deficits in generation and manipulation of mental images: I. The role of sensorimotor speed and working memory.

The authors investigated age-related slowing of information processing in mental imagery tasks. Eighty-five healthy adults (ages 18 to 77) performed a visual, sensorimotor, reaction-time task; a visual-perceptual choice reaction task; and 3 mental imagery tasks that varied in apparent difficulty and involved stimuli at 2 levels of graphic complexity. Age was associated with prolongation of response time across all tasks and both levels of stimulus complexity. Accuracy of response was adversely affected by increase in stimulus complexity in all tasks, whereas it was negatively related to age only on the tasks with substantial mental imagery requirements. Slowing of information processing and reduction in accuracy were mediated by declines in working memory but not by decrease of sensorimotor speed.     

Nature’s drawing: problems and resolutions in the mathematization of motion

The mathematical nature of modern science is an outcome of a contingent historical process, whose most critical stages occurred in the seventeenth century. ‘The mathematization of nature’ (Koyré 1957, From the closed world to the infinite universe, 5) is commonly hailed as the great achievement of the ‘scientific revolution’, but for the agents affecting this development it was not a clear insight into the structure of the universe or into the proper way of studying it. Rather, it was a deliberate project of great intellectual promise, but fraught with excruciating technical challenges and unsettling epistemological conundrums. These required a radical change in the relations between mathematics, order and physical phenomena and the development of new practices of tracing and analyzing motion. This essay presents a series of discrete moments in this process. For mediaeval and Renaissance philosophers, mathematicians and painters, physical motion was the paradigm of change, hence of disorder, and ipso facto available to mathematical analysis only as idealized abstraction. Kepler and Galileo boldly reverted the traditional presumptions: for them, mathematical harmonies were embedded in creation; motion was the carrier of order; and the objects of mathematics were mathematical curves drawn by nature itself. Mathematics could thus be assigned an explanatory role in natural philosophy, capturing a new metaphysical entity: pure motion. Successive generations of natural philosophers from Descartes to Huygens and Hooke gradually relegated the need to legitimize the application of mathematics to natural phenomena and the blurring of natural and artificial this application relied on. Newton finally erased the distinction between nature’s and artificial mathematics altogether, equating all of geometry with mechanical practice.     

Training the brain: fact and fad in cognitive and behavioral remediation

Putatively safe and effective for improving cognitive performance in both health and disease, products purported to train the brain appeal to consumers and healthcare practitioners. In an increasingly health-centered society, these applications constitute a burgeoning commercial market. Sparse evidence coupled with lack of scientific rigor, however, leaves claims concerning the impact and duration of such brain training largely unsubstantiated. On the other hand, at least some scientific findings seem to support the effectiveness and sustainability of training for higher brain functions such as attention and working memory. In the present paper we provide a tectonic integration and synthesis of cognitive training approaches. Specifically, we sketch the relative merits and shortcomings of these programs, which often appeal to parents who must choose between side-effect-laden medication and other less conventional options. Here we examine how neuroplasticity allows the healthy as well the impaired to benefit from cognitive training programs. We evaluate the evidence and consider whether brain training can be a stand-alone treatment or an adjunct to pharmacotherapy, outline promising future prospects, and highlight what training outcomes are plausible in line with available data. Future research would determine whether the field of brain training realizes its potential to revolutionize education and rehabilitation or withers away engulfed in controversy.     

On the Moral Significance of Sacrifice

ABSTRACT

The paper offers a few reflections on moral implications of making sacrifices and on possible duties to make sacrifices. It does not provide an exhaustive or a systematic account of the subject. There are too many disparate questions, and too many different perspectives from which to examine them to allow for a systematic let alone an exhaustive account, and too many factual issues that I am not aware of. Needless to say, the observations that follow are in part stimulated by the popularity of some views that are mistaken. I will not however examine any specific view or account of these matters. The aim is to provide some pointers that will be helpful when considering specific issues regarding the moral significance of sacrifice.     

Aging and the role of working memory resources in visuospatial attention

Visuospatial attention has been shown to be robust to the effects of increasing age. Nonetheless, models linking individual differences in working memory capacity to attentional performance suggest that older adults may experience disruptions in visuospatial attention under conditions of resource load. Two experiments were conducted to investigate the effects of age and concurrent working memory load on two tasks that have been proposed to require posterior attentional processes. The findings suggest that loading working memory resources selectively disrupts performance on a nonintegrated Stroop task, whereas cue utilization remains intact. In addition, imposing a working memory load delays the deployment of visuospatial attention in both experiments. Regarding the effects of age, findings suggest that older adults can effectively perform both attentional tasks despite working memory load. Age differences did emerge in the time course of cue utilization. Findings point to the resilience of visuospatial attention in aging, even under conditions of significant cognitive load. We discuss these results and their implications for models postulating a role for working memory capacity in attentional behaviors.