Face perception is crucial in all social animals. Recent studies have shown that pre-stimulus oscillations of brain activity modulate the perceptual performance of face vs. non-face stimuli, specifically under challenging conditions. However, it is unclear if this effect also occurs during simple tasks, and if so in which brain regions. Here we used magnetoencephalography and a 1-back task in which participants decided if the two sequentially presented stimuli were the same or not in each trial. The aim of the (...) study was to explore the effect of pre-stimulus alpha oscillation on the perception of face and non-face stimuli. Our results showed that pre-stimulus activity in the left occipital face area modulated responses in the intra-parietal sulcus at around 170 ms after the presentation of human face stimuli. This effect was also found after participants were shown images of motorcycles. In this case, the IPS was modulated by pre-stimulus activity in the right OFA and the right fusiform face area. We conclude that pre-stimulus modulation of post-stimulus response also occurs during simple tasks and is therefore independent of behavioral responses. (shrink)

This paper is principally devoted to comparing and contrasting poverty of stimulus arguments for innate cognitive apparatus in relation to language and in relation to folk psychology. These days one is no longer allowed to use the term ‘innate’ without saying what one means by it. So I will begin by saying what I mean by ‘innate’. Sections 2 and 3 will discuss language and theory of mind, respectively. Along the way, I will also briefly discuss other arguments for (...) innate cognitive apparatus in these areas. (shrink)

Traditionally, vision science and information/data visualization have interacted by using knowledge of human vision to help design effective displays. It is argued here, however, that this interaction can also go in the opposite direction: the investigation of successful visualizations can lead to the discovery of interesting new issues and phenomena in visual perception. Various studies are reviewed showing how this has been done for two areas of visualization, namely, graphical representations and interaction, which lend themselves to work on visual (...) processing and the control of visual operations, respectively. The results of these studies have provided new insights into aspects of vision such as grouping, attentional selection and the sequencing of visual operations. More generally yet, such results support the view that the perception of visualizations can be a useful domain for exploring the nature of visual cognition, inspiring new kinds of questions as well as casting new light on the limits to which information can be conveyed visually. (shrink)

Leibovich et al. propose that non-symbolic numerosity abilities develop from the processing of more basic, continuous magnitudes such as size, area, and density. Here I review similar arguments arising in the visual perception field and further propose that the evolvement of discrete representations from continuous stimulus properties may be a fundamental characteristic of cognitive development.

It has been reported that behavior of experts and novices in various sporting tasks is impervious to the introduction of blur. However, studies have used diverse methods of blurring the visual stimulus, and tasks that did not always preserve the normal perception-action coupling. In the current study, we developed a novel experimental protocol to examine the effect of different levels of Gaussian blur on interception performance and eye gaze data using an immersive VR task. Importantly, this provided a realistic (...) simulation of a real-world boxing scenario in which expert combat athletes experienced a first-person, adaptive viewpoint of the visual environment, which could be blurred according to their gaze location. We found that participants exhibited similar interception performance in the presence of central blur or peripheral blur compared to a control condition with no blur. However, interception performance was significantly better with a central blur compared to peripheral blur. Eye gaze data indicated that although participants fixated at similar areas of interest irrespective of the presence of blur, fixation duration was significantly longer with a strong level of blur in the peripheral viewing condition than all levels of central blur and the control condition. These findings can be explained by relocating attention to different areas of the environment, which thereby influenced the perception of salient information. Participants also performed better on the first punch of a sequence preceded by a foot feint compared to arm feint or no feint. Still, irrespective of feint type, performance was significantly better on the second and third punch compared to the first punch. These findings are consistent with participants using additional information from the opponent's body movements and situational probabilities to increase performance as the sequence of punches developed. Overall, these are the first evidence for the use of VR as a means to examine gaze-contingent manipulations of the environment, and hence highlight the potential for facilitating learning and transfer to a real sporting situations. (shrink)

This paper seeks a deeper understanding of the congener as a factor in animal and human behaviour. It does so, not by concentrating on analyses of stimulus exchanges - largely specific to the species - by which a congener is recognized, but on the more general questions of why a notion of congener exists at all and why it plays such an extraordinary important role in animal and human behaviour.Three separate approaches, by way of anthropomorphic psychology, a paraphysical energy (...) model and the physical theory of the implicate order, lead to the recognition of a certain inseparability of self and congener; and to an interpretation of the content of the notion of congener and of the behaviour in relation to it, in terms of the fundamental concept of energy and the even more fundamental one of order. (shrink)

The neural substrates of context effects in word perception are still largely unclear. Interhemispheric priming phenomena in word recognition, typically observed in normal subjects, are absent in commissurotomized patients. This suggests that callosal fibers may provide contextual integration. In addition, certain characteristics of human frontal cortical fields subserving sensorimotor learning, as investigated by positron emission tomography, provide evidence for contextual integration not confined to the visual system. This supports the notion of common aspects of cortical computations in different cerebral (...) class='Hi'>areas. (shrink)

Creating focal lesions in primary visual cortex (V1) provides an opportunity to study the role of extra-geniculo-striate pathways for activating extrastriate visual cortex. Previous studies have shown that more than 95% of neurons in macaque area V2 and V3 stop firing after reversibly cooling V1 [1,2,3]. However, no studies on long term recovery in areas V2, V3 following permanent V1 lesions have been reported in the macaque. Here we use macaque fMRI to study area V2, V3 activity patterns from (...) 1 to 22 months after lesioning area V1. We find that visually driven BOLD responses persist inside the V1-lesion projection zones (LPZ) of areas V2 and V3, but are reduced in strength by ,70%, on average, compared to prelesion levels. Monitoring the LPZ activity over time starting one month following the V1 lesion did not reveal systematic changes in BOLD signal amplitude. Surprisingly, the retinotopic organization inside the LPZ of areas V2, V3 remained similar to that of the non-lesioned hemisphere, suggesting that LPZ activation in V2, V3 is not the result of input arising from nearby (non-lesioned) V1 cortex. Electrophysiology recordings of multi-unit activity corroborated the BOLD observations: visually driven multi-unit responses could be elicited inside the V2 LPZ, even when the visual stimulus was entirely contained within the scotoma induced by the V1 lesion. Restricting the stimulus to the intact visual hemi-field produced no significant BOLD modulation inside the V2, V3 LPZs. We conclude that the observed activity patterns are largely mediated by parallel, V1-bypassing, subcortical pathways that can activate areas V2 and V3 in the absence of V1 input. Such pathways may contribute to the behavioral phenomenon of blindsight. (shrink)

As ciências médicas, biomédicas, humanas e sociais têm avançado de forma frenética nos últimos anos. Com isso, se faz cada vez mais necessário o debate ético que visa contemplar o respeito à dignidade humana, animal e ao meio ambiente. A bioética se dedica a esse debate e se propõe a estendê-lo a setores não acadêmicos, como sociedades de proteção dos animais, dos direitos humanos e até grupos religiosos. Essa diversidade de opiniões não só é interessante, mas necessária, uma vez que (...) os valores praticados em uma sociedade provêm de uma construção social cujos blocos fundamentais têm origem na família e nos diversos grupos sociais nos quais os indivíduos estão inseridos desde o seu nascimento. A proposta deste livro é fomentar esse debate, fornecendo conceitos e visões sobre temas selecionados da pesquisa e da prática médica, biotecnológica e de áreas correlatas. Em um contexto mundial de intolerância política, social, étnica e de gênero, oportunidades de debate também possuem um papel social de auxiliar no desenvolvimento consciente da cidadania e do respeito ao próximo. Sobretudo, o debate nos faz enxergar o outro como parelho, ainda que cada um possua as suas especificidades, opiniões e histórias de vida. (shrink)

No início dos anos 40, Gilda de Mello e Souza publicou contos, dando início a uma experiência na ficção brasileira posteriormente interompida. Este ensio procura mostrar as razões da incompreensão com que foram recebidos esses contos e lamenta a perda que significou a desistência da criação literária por parte da autora.

Hace ya más de una década que se acuñó el concepto de "elearning", docencia virtual, aprendizaje online y otros similares para referirse a los procesos formativos apoyados total o parcialmente a través de las TIC en general, y particularmente, mediante entornos online. Desde entonces hasta el presente este formato de docencia y aprendizaje ha dejado de ser un fenómeno minoritario para convertirse en una modalidad de oferta educativa generalizada en muchas instituciones formativas.

Eye-tracking studies have revealed a specific visual exploration style characterizing individuals with Autism Spectrum Disorder (ASD). The aim of this study is to investigate the impact of stimulus type (static vs. dynamic) on visual exploration in children with ASD. Twenty-eight children with ASD, 28 children matched for developmental communication age and 28 children matched for chronological age watched a video and a series of photos involving the same joint attention scene. For each stimulus, Areas of Interest (AOI) (...) were determined based on Voronoi diagrams, which were defined around participants’ fixation densities, defined by the mean shift algorithm. To analyze the eye-tracking data on visual exploration, we used a method for creat-ing AOI a posteriori, based on participants’ actual fixations. The results showed the value of both kinds of stimuli. The photos allowed for the identification of more precise AOI, and show similarities in exploration between ASD and typical children. On the other hand, in video, among ASD children only, there are few differences in the way they look at the target depend-ing on the deictic cue used. This raises questions regarding their understanding of a joint atten-tion bid recorded on a video. Finally, whatever the stimulus, pointing seems to be the most im-portant element for children to look at the target. (shrink)

Democracy has been a flawed hegemony since the fall of communism. Its flexibility, its commitment to equality of representation, and its recognition of the legitimacy of opposition politics are all positive features for political institutions. But democracy has many deficiencies: it is all too easily held hostage by powerful interests; it often fails to advance social justice; and it does not cope well with a number of features of the political landscape, such as political identities, boundary disputes, and environmental crises. (...) Although democracy is valuable it fits uneasily with other political values and is in many respects less than equal to the demands it confronts. In this volume prominent political theorists and social scientists present original discussions of such central issues. Democracy's Values deals with the nature and value of democracy, particularly the tensions between it and such goods as justice, equality, efficiency, and freedom. (shrink)

Auf dem Gebiete des Gesichtssinnes gelten an der phänomenalen, absoluten Schwelle die begrifflichen, linearen ReizausdrückeL. t = Konstante bzw.L. f = Konstante, in denenL die physikalische Lichtintensität,t die Reizzeitdauer undf die Reizfläche bedeuten . Der zeitliche Gültigkeitsbereich des erstgenannten Ausdrucks erstreckt sich von ganz kurzen bis zu Zeitdauern von etwa 100σ, d.h. bis zu Zeitdauern die phänomenal eben noch als momentan empfunden werden. Entsprechend scheint sich der Gültigkeitsbereich des zweitgenannten Ausdrucks nur bis zu solchen Flächengrössen zu erstrecken, die phänomenal eben (...) noch als punktuell erscheinen. Bei phänomenal momentanen, punktuellen und minimalintensiven Gesichtserlebnissen, also bei in allen Hinsichten differentieller Phänomenalität gilt der trilineare ReizausdruckL. f. t = Konstante. Für überschwellige Lichtempfindungen gelten keine linearen Ausdrücke; alle aufgestellten sind kompliziert und ziemlich undurchsichtig . Es wird darauf hingewiesen, dass auf dem Gebiete des Gehörssinnes ähnliche Verhältnisse wie auf dem Gebiete des Gesichtes vorliegen.Die einflache Linearität der begrifflichen Reizausdrücke einerseits, wenn sie differentielle, in allen Hinsichten phänomenal minimale Erlebnisse wiedergeben, und andererseits die komplizierte Struktur der Ausdrücke, wenn sie überschwellige Phänomenalitäten wiedergeben, bezeugen, dass hier ein Strukturproblem vorliegt, welches im Zusammenhang mit dem gegenseitigen Verhältnis vom Phänomenalen und Begrifflichen steht. Dieser Problemkomplex wird in dieser Abhandlung zu behandeln versucht.In the field of vision the absolute phenomenal threshold may be expressed by the conceptual linear stimulus equation:L. t = const., respectivelyL. f = const., in whichL denotes the physical brightness intensity of light,t the stimulus duration andf the stimulus area . For the former expression the temporal limits of validity extend from quite short durations up to 100σ i.e. up to duration of apparent momentariness. Correspondingly the validity of the second equation seems to extend barely to area values that appear phenomenally punctual . In case of phenomenally momentary and punctual visual perceptions and of those being phenomenally of minimal brightness,i.e. in case of an in every point differential phenomenality the trilinear equation holds true:L. f. t = const. Concerning the supraliminal visual perceptions no such linear expression is valid. If, however, it would be possible to construct an equation representing the phenomenality of supraliminal visual perceptions, it would be very complicated and of little clarity . It is pointed out, that in the field of audition there exist similar relations as in the field of visual perceptions.The simple linearity of conceptual stimulus equations, when they denote differential, in every respect phenomenally minimal perceptions and on the other hand the complicated structure of expressions corresponding to supraliminal phenomenalities, show, that there exists a structural problem connected with the phenomenal and conceptual field.An attempt is made to settle this complex of problems.Dans le domaine du sens visuel on peut appliquer au seuil phénoménal absolu les expressions d'excitation linéairesL. t = constante, respectivementL. f = constante. Dans ces expressionsL signifie l'intensité lumineuse physique,t le temps de l'excitation etf la surface de l'excitation . Le domaine de la validité du temps de la première expression s'étend d'un temps très court jusqu'à un espace de temps d'env. 100σ c'est-à-dire jusqu'à des périodes de temps qu'on peut encore percevoir comme phénoménalement momentanées. En analogie avec ceci le domaine de validité de la deuxième expression mentionnée semble s'étendre seulement jusqu'à de telles surfaces qui apparaissent encore phénoménalement ponctuelles. Dans les perceptions visuelles phénoménalement momentanées, ponctuelles et d'un minimum d'intensité, par conséquent dans une phénoménalité sous tous les rapports différentielle, on peut appliquer l'expression d'excitation trilinéaireL. f. t = constante. En ce qui concerne les sensations lumineuses dépassant le seuil il n′y a aucunes expressions linéaires pour les rendre; dans le cas oú l'on pourrait en établir, elles sont compliquées . Il est indiqué que dans le domaine du sens de l'ouïe il se présente des conditions analogues que dans le domaine du sens visuel.La linéarité simple des expressions d'excitation applicable aux cas des sensations différentielles, c'est-à-dire des sensations sous tous les rapports phénoménalement minimes, et de l'autre côté, la structure compliquée des expressions, correspondant à des phénoménalités dépassant le seuil, montrent, qu'il est question ici d'un problème de structure qui est associé à la relation réciproque des phénoménalités et des fonctionalités. Dans cet article l'auteur essaie d'élucider ce complexe de problèmes. (shrink)

1 – Institute for Frontier Areas of Psychology and Mental Health, Wilhelmstr. 3a, 79098 Freiburg, Germany 2 – Parmenides Center, Via Mellini 26-28, 57031 Capoliveri, Italy 3 – Department of Ophtalmology, University of Freiburg, Killianstr. 5, 79106 Freiburg, Germany 4 – Institute of Physics, University of Freiburg, Hermann- Herder -Str. 3, 79104 Freiburg, GermanyThe “Necker-Zeno model”, a model for bistable perception inspired by the quantum Zeno effect, was previously used to relate three basic time scales of cognitive relevance to (...) one another in a quantitative manner. In this paper, the model predictions are compared with experimental results obtained under discontinuous presentation of an ambiguous stimulus. In addition to earlier results for long inter-stimulus intervals, we show that the reversal dynamics according to the Necker-Zeno model is also in agreement with new results for short inter-stimulus intervals. Moreover, we refine the model in such a way that it accounts for the distribution of “dwell times”. Finally, we indicate applications concerning the modification of cognitive time scales under conditions of psychopathological impairments and meditationinduced modes of awareness. ∗Address correspondence to this author at the Theory Division of the Institute for Frontier Areas of Psychology, Wilhelmstr. 3a, D–79098 Freiburg, Germany; E-mail: [email protected]. (shrink)

Responding to the stimulus afforded by Little et al.’s “Pragmatic pluralism: Mutual tolerance of contested understandings between orthodox and alternative practitioners in autologous stem cell transplantation,” this paper explores how the norms of qualitative inquiry affect the representation of emotion in research reports. It describes a conflict between the construction of emotion in qualitative research accounts and its application to analysis and theorization, whose origins may lie in researchers’ reticence when it comes to conveying or using the emotional features (...) of data. The technical aspects of report writing that are associated with this conflict are explored via a deconstruction of Little et al.’s paper and a survey of the qualitative research methods literature. Writing to convey emotion and analysing to include author-constructed emotional context are neglected topics. Using data in Little et al.’s text, the paper demonstrates the importance of author-constructed emotional context to theory generation. The paper recommends the inclusion of emotional context as data in analysis and points to lessons Little et al.’s paper offers in the areas of narrative technique and reflexive practice. (shrink)

Blindsight is the term commonly used to describe visually guided behaviour elicited by a stimulus falling within the scotoma (blind area) caused by a lesion of the striate cortex. Such is normally held to be unconscious and to be mediated by subcortical pathways involving the superior colliculus. Blindsight is of considerable theoretical importance since it suggests that destriate man is more like destriate monkey than had been previously believed and also because it supports the classical notion of two visual (...) systems. It is also of potential clinical importance, since it has been claimed recently that systematic practice in blindsight can lead to the recovery of normal visual function in patients with cortical lesions. From a review of the literature it is concluded that all of the phenomena of blindsight can be attributed either to light scatter into unimpaired parts of the visual field or to residual vision resulting from spared striate cortex. The possible contribution f other factors is also considered. It is concluded that blindsight studies have generally failed to control for such nonblindsight interpretations partly because of poor methodology and partly because of difficulties in defining the term. (shrink)

Conscious perception, like the sight of a coffee cup, seems to involve the brain identifying a stimulus. But conscious input activates more brain regions than are needed to identify coffee cups and faces. It spreads beyond sensory cortex to frontoparietal association areas, which do not serve stimulus identification as such. What is the role of those regions? Parietal cortex support the ‘first person perspective’ on the visual world, unconsciously framing the visual object stream. Some prefrontal areas (...) select and interpret conscious events for executive control. Such functions can be viewed as properties of the subject, rather than the object, of experience – the ‘observing self’ that appears to be needed to maintain the conscious state. (shrink)

Implicit learning is said to occur when a person learns about a complex stimulus without necessarily intending to do so, and in such a way that the resulting knowledge is difficult to express. Over the last 30 years, a number of studies have claimed to show evidence of implicit learning. In more recent years, however, considerable debate has arisen over the extent to which cognitive tasks can in fact be learned implicitly. Much of the debate has centred on the (...) questions of how unconscious, and how abstract, is implicitly acquired knowledge? The aim of this book is to provide students and researchers with a self-contained and balanced summary of the various theoretical and empirical positions that are currently shaping this exciting area of research. (shrink)

Because little is known about the human trait of affiliation, we provide a novel neurobehavioral model of affiliative bonding. Discussion is organized around processes of reward and memory formation that occur during approach and consummatory phases of affiliation. Appetitive and consummatory reward processes are mediated independently by the activity of the ventral tegmental area (VTA) dopamine (DA)–nucleus accumbens shell (NAS) pathway and the central corticolimbic projections of the u-opiate system of the medial basal arcuate nucleus, respectively, although these two projection (...) systems functionally interact across time. We next explicate the manner in which DA and glutamate interact in both the VTA and NAS to form incentive-encoded contextual memory ensembles that are predictive of reward derived from affiliative objects. Affiliative stimuli, in particular, are incorporated within contextual ensembles predictive of affiliative reward via: (a) the binding of affiliative stimuli in the rostral circuit of the medial extended amygdala and subsequent transmission to the NAS shell; (b) affiliative stimulus-induced opiate potentiation of DA processes in the VTA and NAS; and (c) permissive or facilitatory effects of gonadal steroids, oxytocin (in interaction with DA), and vasopressin on (i) sensory, perceptual, and attentional processing of affiliative stimuli and (ii) formation of social memories. Among these various processes, we propose that the capacity to experience affiliative reward via opiate functioning has a disproportionate weight in determining individual differences in affiliation. We delineate sources of these individual differences, and provide the first human data that support an association between opiate functioning and variation in trait affiliation. Key Words: affiliation corticolimbic-striatal networks; appetitive and consummatory reward; dopamine; oxytocin; personality; social bonds; social memory; u-opiates. (shrink)

Under the stimulus of developing commercial economy and overseas trade, the social customs characterized by prevailing luxury and extravagance was gradually formed in Fujian Province from the mid-Ming Dynasty on. The transformation started from the material culture and later spread to people’s mental attitudes including the public ethics and human relations. Compared with what happened in the Jiangnan area, the change in Fujian Province was less profound and thorough, but it highly surpassed the North China society, where many sub-prefectures (...) and counties remained unchanged till the end of the Ming Dynasty. However, there were also some coastal or interior regions in Fujian which continuously maintained a simple and unspoiled social atmosphere for the unbalanced economic development. (shrink)

If the cortex is an associative memory, strongly connected cell assemblies will form when neurons in different cortical areas are frequently active at the same time. The cortical distributions of these assemblies must be a consequence of where in the cortex correlated neuronal activity occurred during learning. An assembly can be considered a functional unit exhibiting activity states such as full activation (“ignition”) after appropriate sensory stimulation (possibly related to perception) and continuous reverberation of excitation within the assembly (a (...) putative memory process). This has implications for cortical topographies and activity dynamics of cell assemblies forming during language acquisition, in particular for those representing words. Cortical topographies of assemblies should be related to aspects of the meaning of the words they represent, and physiological signs of cell assembly ignition should be followed by possible indicators of reverberation. The following postulates are discussed in detail: (1) assemblies representing phonological word forms are strongly lateralized and distributed over perisylvian cortices; (2) assemblies representing highly abstract words such as grammatical function words are also strongly lateralized and restricted to these perisylvian regions; (3) assemblies representing concrete content words include additional neurons in both hemispheres; (4) assemblies representing words referring to visual stimuli include neurons in visual cortices; and (5) assemblies representing words referring to actions include neurons in motor cortices. Two main sources of evidence are used to evaluate these proposals: (a) imaging studies focusing on localizing word processing in the brain, based on stimulus-triggered event-related potentials (ERPs), positron emission tomography (PET), and functional magnetic resonance imaging (fMRI), and (b) studies of the temporal dynamics of fast activity changes in the brain, as revealed by high-frequency responses recorded in the electroencephalogram (EEG) and magnetoencephalogram (MEG). These data provide evidence for processing differences between words and matched meaningless pseudowords, and between word classes, such as concrete content and abstract function words, and words evoking visual or motor associations. There is evidence for early word class-specific spreading of neuronal activity and for equally specific high-frequency responses occurring later. These results support a neurobiological model of language in the Hebbian tradition. Competing large-scale neuronal theories of language are discussed in light of the data summarized. Neurobiological perspectives on the problem of serial order of words in syntactic strings are considered in closing. Key Words: associative learning; cell assembly; cognition; cortex; ERP; EEG; fMRI; language; lexicon; MEG; PET; word category. (shrink)

There is growing consensus that reward plays an important role in the control of attention. Until recently, reward was thought to influence attention indirectly by modulating task-specific motivation and its effects on voluntary control over selection. Such an account was consistent with the goal-directed (endogenous) versus stimulus-driven (exogenous) framework that had long dominated the field of attention research. Now, a different perspective is emerging. Demonstrations that previously reward-associated stimuli can automatically capture attention even when physically inconspicuous and task-irrelevant challenge (...) previously held assumptions about attentional control. The idea that attentional selection can be value driven, reflecting a distinct and previously unrecognized control mechanism, has gained traction. Since these early demonstrations, the influence of reward learning on attention has rapidly become an area of intense investigation, sparking many new insights. The result is an emerging picture of how the reward system of the brain automatically biases information processing. Here, I review the progress that has been made in this area, synthesizing a wealth of recent evidence to provide an integrated, up-to-date account of value-driven attention and some of its broader implications. (shrink)

A number of ways of taxonomizing human learning have been proposed. We examine the evidence for one such proposal, namely, that there exist independent explicit and implicit learning systems. This combines two further distinctions, (1) between learning that takes place with versus without concurrent awareness, and (2) between learning that involves the encoding of instances (or fragments) versus the induction of abstract rules or hypotheses. Implicit learning is assumed to involve unconscious rule learning. We examine the evidence for implicit learning (...) derived from subliminal learning, conditioning, artificial grammar learning, instrumental learning, and reaction times in sequence learning. We conclude that unconscious learning has not been satisfactorily established in any of these areas. The assumption that learning in some of these tasks (e.g., artificial grammar learning) is predominantly based on rule abstraction is questionable. When subjects cannot report the rules that govern stimulus selection, this is often because their knowledge consists of instances or fragments of the training stimuli rather than rules. In contrast to the distinction between conscious and unconscious learning, the distinction between instance and rule learning is a sound and meaningful way of taxonomizing human learning. We discuss various computational models of these two forms of learning. (shrink)

A number of ways of taxonomizing human learning have been proposed. We examine the evidence for one such proposal, namely, that there exist independent explicit and implicit learning systems. This combines two further distinctions, between learning that takes place with versus without concurrent awareness, and between learning that involves the encoding of instances versus the induction of abstract rules or hypotheses. Implicit learning is assumed to involve unconscious rule learning. We examine the evidence for implicit learning derived from subliminal learning, (...) conditioning, artificial grammar learning, instrumental learning, and reaction times in sequence learning. We conclude that unconscious learning has not been satisfactorily established in any of these areas. The assumption that learning in some of these tasks is predominantly based on rule abstraction is questionable. When subjects cannot report the “implicitly learned” rules that govern stimulus selection, this is often because their knowledge consists of instances or fragments of the training stimuli rather than rules. In contrast to the distinction between conscious and unconscious learning, the distinction between instance and rule learning is a sound and meaningful way of taxonomizing human learning. We discuss various computational models of these two forms of learning. (shrink)

This article seeks the origin, in the theories of Ibn al-Haytham (Alhazen), Descartes, and Berkeley, of two-stage theories of spatial perception, which hold that visual perception involves both an immediate representation of the proximal stimulus in a two-dimensional ‘‘sensory core’’ and also a subsequent perception of the three dimensional world. The works of Ibn al-Haytham, Descartes, and Berkeley already frame the major theoretical options that guided visual theory into the twentieth century. The field of visual perception was the first (...) area of what we now call psychology to apply mathematics, through geometrical models as used by Euclid, Ptolemy, Ibn al-Haytham, and Descartes (among others). The article shows that Kepler’s discovery of the retinal image, which revolutionized visual anatomy and entailed fundamental changes in visual physiology, did not alter the basic structure of theories of spatial vision. These changes in visual physiology are advanced especially in Descartes' Dioptrics and his L'Homme. Berkeley develops a radically empirist theory vision, according to which visual perception of depth is learned through associative processes that rely on the sense of touch. But Descartes and Berkeley share the assertion that there is a two-dimensional sensory core that is in principle available to consciousness. They also share the observation that we don't usually perceived this core, but find depth and distance to be phenomenally immediate, a point they struggle to accommodate theoretically. If our interpretation is correct, it was not a change in the theory of the psychology of vision that engendered the idea of a sensory core, but rather the introduction of the theory into a new metaphysical context. (shrink)

Chapter 1 serves as an introduction to the vast topic of laws of nature. Thus, it first outlines the alleged characteristics of the laws of nature, namely truth, objectivity, contingency, necessity, universality, grounding counterfactuals and their role in science. Among these aspects, the peculiar modal status of laws of nature will be identified as the ‘holy grail’ of the debate. The second part of this chapter is concerned with the three main families of theories of laws of nature – neo-humean, (...) ADT and dispositional theories – which are introduced and evaluated in regard to the aforementioned characteristics. It will then be argued that among those theories, the dispositional ones show the greatest promise of being able to account for the natural necessity of the laws of nature. -/- Before a dispositional account of laws of nature can be given, dispositions themselves need to be understood. Consequently, Chapter 2 introduces various analyses of dispositions. As dispositions are pre-theoretically close to conditionals, a lot of analyses try to reduce dispositions to conditionals. This chapter critically assesses some chosen accounts: the simple conditional analysis, Carnap’s reduction sentences, the simple counterfactual conditional analysis, Lewis’ reformed conditional analysis, Malzkorn’s sophisticated con- ditional analysis, Choi and Gundersen’s context-dependent analysis, Manley and Wasserman’s gradable dispostion ascriptions, and Fara’s habituals. The prevention problem, which poses a threat to any account of dispositions, is depicted. It is argued that, ultimately, none of the conditionalising attempts is able to convince since they all exclude the problem cases which leads to explanation gaps and outlaw areas. -/- Chapter 3 contains the synchronic part of my preferred solution to the prevention problem. The notion of ‘component causes’ is introduced, and the ontological status of components discussed. Millikan’s oil drop experiment is depicted en detail. In a first step, making a distinction between dispositions and the resulting behaviour is advocated. Via the symmetry argument, mani- festations and masks are shown to be ontologically on a par. In a second step, a triadic account consisting of dispositions, wirkungen and resultant behaviour, is established. Finally, the ontological interpretation of the trias is given. It is in the nature of the dispositions to bring about the wirkungen. These interact via combinations rules like the functions f and fa or vector addition, which are built-in into to dispositions. -/- The diachronic part of my favourite interpretation, the triadic process picture of dispositions (TPD), is presented in chapter 4. The dynamics of dispo- sition manifestation are discussed and it is argued that fiddling with the trigger works only up to a certain point. Diachronic masking cases turn out to be no- torious. An excursus to action theory shows that the ontology needs to include processes, as understanding disposition manifestations as processes solves the diachronic prevention problem. The (TPD) can account for all counterexamples by taking the stimulus as the beginning of the manifestation process. -/- Chapter 5 applies the (TPD) to the debate about laws of nature. In order to judge its adequacy, the characteristics of laws of nature given in chapter 1 are consulted. As a first step, the criteria truth, objectivity, universality, grounding counterfactuals and their role in science are covered. It is sketched how the (TPD) can account for these. The second part of the chapter deals with the modal status of the laws of nature. The dispositional essentialist’s view that laws of nature are metaphysical necessary is depicted and then criticised. It is argued that metaphysical necessity is not the appropriate modal status of the laws of nature. Finally, the (TPD) account of the necessity of the laws of nature is presented: laws of nature are naturally necessary and metaphysically contingent. (shrink)