Shors & Matzel propose that hippocampal LTP increases the effective salience of discrete external stimuli and thereby facilitates the induction of memories at distant places. In line with this suggestion, a neural network model of associative learning and hippocampal function assumes that LTP increases hippocampal error signals to the cortex, thereby facilitating stimulus configuration in association cortex. Computer simulations show that under these assumptions the model correctly describes the effect of LTP induction and blockade in classical discriminations and place (...) learning. (shrink)

This commentary raises the possibility of recent discussion on the issue of basic color terms suffering from the "stimulus error," first described by the English psychologist E. B. Titchener. It refers to confusion of the psychological experience with the physical description of the stimulus. Such confusion is routine in everyday language in situations where private sensory experiences are involved that cannot be objectively described, but is harmful in fundamental discussions about experiences.

À Harvard durant l’année académique 1940-41, les philosophes-mathématiciens Quine, Tarski et Carnap débattaient de la possibilité d’établir une distinction entre les énoncés analytiques et synthétiques qui soit suffisamment mordante pour dégager un statut spécial à l’épistémologie. Quine et Tarski s’objectaient à la distinction et l’objection de Quine verra notamment le jour sous le titre fameux « Les deux dogmes de l’empirisme ». Carnap, dans son autobiographie intellectuelle, se souvient avoir alors craint : « are we now back to John Stuart (...) Mill? ». Carnap avait compris qu’une épistémologie antipsychologiste comme celle du Cercle de Vienne ne peut subsister sans la présence d’une distinction de principe entre des énoncés analytiques et synthétiques. Il avait compris qu’un rejet de la distinction signifiait, à court ou moyen terme, un retour à l’épistémologie comme « psychologie de la science » telle que la pratiquait Auguste Comte, John Stuart Mill et Ernst Mach. (shrink)

In the debates surrounding the ethical dimensions of interventions in the human genome, much attention is paid to determining whether—and if so, how—market access to these technologies ought to be managed in order to maximize social benefit. There are those who advocate a “laissez-faire” free-market approach to the development and use of genetic and genomic interventions. We are sympathetic to this view insofar as we understand the workings of the market stimulus effect. We use the term “market stimulus (...) effect” to refer to the outcome of a set of mechanisms whereby early adoption of a new technology by wealthy consumers promotes the development of versions of this product that are cheaper to produce, or are simply .. (shrink)

Heyman's analysis of addiction in terms of matching to local relative value can be supplemented by stimulus-control processes. Stimulus equivalence can broaden the set of situations that occasion addictive behavior, and the situation-reinforcer correlation can enhance its persistence. The joint effects of stimulus-control and reinforcement processes may complicate treatment.

A detection task was performed using different pictographic representations of objects in order to test the hypothesis that high-level information (familiarity) may influence detection thresholds. The stimuli were five versions of forms: outline drawings of objects, silhouettes, and three fragmented versions of forms derived from the outlines. The stimuli varied on two parameters: their nameability (easily nameable, hardly nameable, and not nameable) as assessed by a naming task, and their energy content as assessed by a two-dimensional fast-Fourier transform. The greatest (...) amount of energy was observed for silhouettes, and the amount of energy contained in the vertical and horizontal spatial frequency components was equivalent for outlines and the three versions of fragmented forms. Luminance thresholds for the detection of the forms were measured by means of an adaptive method. The results show that thresholds were determined only by the energy content of the stimuli. High-level semantic or name information had no influence on the detectability of the visual signal. The results are discussed in terms of the visibility of spatial frequency components at detection threshold. (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)

This study aims to contribute to emerging human-robot interaction research by adding longitudinal findings to a limited number of long-term social robotics home studies. We placed 70 robots in users’ homes for a period of up to six months, and used questionnaires and interviews to collect data at six points during this period. Results indicate that users’ evaluations of the robot dropped initially, but later rose after the robot had been used for a longer period of time. This is congruent (...) with the so-called mere-exposure effect, which shows an increasing positive evaluation of a novel stimulus once people become familiar with it. Before adoption, users focus on control beliefs showing that previous experiences with robots or other technologies allows to create a mental image of what having and using a robot in the home would entail. After adoption, users focus on utilitarian and hedonic attitudes showing that especially usefulness, social presence, enjoyment and attractiveness are important factors for long-term acceptance. (shrink)

Long-term potentiation is one of the most extensively studied forms of neuroplasticity and is considered the strongest candidate mechanism for memory and learning. The use of event-related potentials and sensory stimulation paradigms has allowed for the translation from animal studies to non-invasive studies of LTP-like synaptic plasticity in humans. Accumulating evidence suggests that synaptic plasticity as measured by stimulus-specific response modulation is reduced in neuropsychiatric disorders such as major depressive disorder, bipolar disorders and schizophrenia, suggesting that impaired synaptic plasticity (...) plays a part in the underlying pathophysiology of these disorders. This is in line with the neuroplasticity hypothesis of depression, which postulate that deficits in neuroplasticity might be a common pathway underlying depressive disorders. The current study aims to replicate and confirm earlier reports that visual stimulus-specific response modulation is a viable probe into LTP-like synaptic plasticity in a large sample of healthy adults. Further, this study explores whether impairments in LTP-like synaptic plasticity is associated with self-reported subclinical depressive symptoms and stress in a healthy population. Consistent with prior research, the current study replicated and confirmed reports demonstrating significant modulation of visual evoked potentials following visual high-frequency stimulation. Current results further indicate that reduced LTP-like synaptic plasticity is associated with higher levels of self-reported symptoms of depression and perceived stress. This indicate that LTP-like plasticity is sensitive to sub-clinical levels of psychological distress, and might represent a vulnerability marker for the development of depressive symptoms. (shrink)

Recent research suggests that processing of irrelevant information can be modulated in a rapid online fashion by contextual information in the task environment depending on the usefulness of that information in different contexts. Congruency effects evoked by irrelevant stimulus attributes are smaller in contexts with high proportions of incongruent trials and larger in contexts with high proportions of congruent trials . The present study investigates these context-adaptation effects in a masked-priming paradigm. Context-specific adaptation effects transfer to stimulus identities (...) that are equiprobale in all contexts – an observation that renders explanations in terms of event-learning processes unlikely. Yet, context-specific effects vanished when the irrelevant information remained unconscious. The results suggest that context-specific adaptation of congruency effects reflect cognitive control operations that alter the processing of irrelevant information depending on the experienced utility of that information for action control. (shrink)

Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. However, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide variety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits (...) will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recoding of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity-limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed. Key Words: attention; enumeration; information chunks; memory capacity; processing capacity; processing channels; serial recall; short-term memory; storage capacity; verbal recall; working memory capacity. (shrink)

Habituation is defined as a decline in responding to a repeated stimulus. After more than eighty years of research, there is an enduring consensus among researchers on the existence of 9-10 behavioral regularities or parameters of habituation. There is no similar agreement, however, on the best approach to explain these facts. In this paper, we demonstrate that the Sometimes Opponent Processes (SOP) model of stimulus processing accurately describes all of these regularities. This model was proposed by Allan Wagner (...) as a quantitative elaboration of Priming Theory, which states that the processing of a stimulus, and therefore its capacity to provoke its response, depends inversely on the degree to which the stimulus is pre-represented in short-term memory. Using computer simulations, we show that all the facts involving within-session effects or short-term habituation might be the result of priming from recent presentations of the stimulus (self-generated priming). The characteristics involving between-sessions effects or long-term habituation would result from the retrieval of the representation of the stimulus from memory by the associated context (associatively-generated priming). (shrink)

The degree to which physiology and culture have affected the formation of primitive color categories continues to be a matter of discussion. In this paper the degree of agreement between the ranges of individual color term foci for the four hue-based color categories yellow, green, blue, and red and individual choices of Munsell samples representing for the observers Hering's four unique hues is investigated. The color term focus range data are extracted from the survey results of the 110 unwritten languages (...) of the World Color Survey, also in terms of the Munsell color order system. Agreement of approximately 90% between the two has been found, indicating the likelihood of a strong color vision system related physiological component in the formation of these four primitive hue categories. (shrink)

ABSTRACTIn verbal communication, affective information is commonly conveyed to others through spatial terms. This study used a target location discrimination task with neutral, positive and negative stimuli to test the automaticity of the emotion-space association, both in the vertical and horizontal spatial axes. The effects of stimulus type on emotion-space representations were also probed. A congruency effect was observed in the vertical axis: detection of upper targets preceded by positive stimuli was faster. This effect occurred for all (...) class='Hi'>stimulus types, indicating that the emotion-space association is not dependent on sensory modality and on the verbal content of affective stimuli. (shrink)

In "Does the Basic Color Terms discussion suffer from the Stimulus Error?" Rolf Kuehni describes a research stumbling block known as the "stimulus error," and hints at the difficulties it causes for mainstream color naming research. Among the issues intrinsic to Kuehni's "stimulus error" description is the important question of what can generally be inferred from color naming behaviors based on bounded samples of empirical stimuli. Here we examine some specifics of the color naming research issues (...) that Kuehni raises. While we share Kuehni's view regarding potential problems caused by the "stimulus error" and his concern regarding its prevalence, Kuehni's commentary seems primarily aimed at stimulating a general discussion of color naming research implications, because the articles he critiques do not actually commit the "stimulus error" in any serious sense. Based on Kuehni's comments, we further examine some of the relevant empirical and theoretical implications for cross-cultural color naming research. (shrink)

This paper examines the theoretical differences obtaining between a mechanist like Moore and a teleologist like Rychlak. It is shown that mechanistic formulations invariably reduce the account to material and efficient causation, whereas teleologists want to bring in formal-final cause descriptions as well. Mechanists frame their explanations in third-person terms whereas teleologists often seek a first-person formulation of behavior. Moore's references to "private events" are shown to be extraspectively understood. A major theme of this paper is that Skinner actually (...) capitalized on the intentional nature of human behavior, and that it would be fairly easy to reconceptualize his theory and its empirical support in teleological terms. Careful examination of both the contingency and the discriminative-stimulus constructs are made in support of this contention. (shrink)

Nitric oxide (NO) is involved in synaptic long-term potentiation (LTP) by multiple signaling pathways. Here, we show that LTP of synaptic transmission can be explained as a feature of signal transduction—bistable behavior in a chain of biochemical reactions with positive feedback, formed by diffusion of NO to the presynaptic site and facilitating the release of glutamate (Glu). The dynamics of Glu, calcium (Ca2+) and NO is described by a system of nonlinear reaction–diffusion equations with modified Michaelis–Menten (MM) kinetics. Numerical investigation (...) reveals that the chain of biochemical reactions analyzed can exhibit a bistable behavior under physiological conditions when production of Glu is described by MM kinetics and decay of NO is modeled by means of two enzymatic pathways with different kinetic properties. Our finding extends understanding of the role of NO in LTP: a short high-intensity stimulus is “memorized” as a long-lasting elevation of NO concentration. The conclusions obtained by analysis of the chain of biochemical reactions describing LTP can be generalized to other chains of interactions or for creating the logical elements for biological computers. (shrink)

According to one productive and influential approach to cognition, categorization, object recognition, and higher level cognitive processes operate on a set of fixed features, which are the output of lower level perceptual processes. In many situations, however, it is the higher level cognitive process being executed that influences the lower level features that are created. Rather than viewing the repertoire of features as being fixed by low-level processes, we present a theory in which people create features to subserve the representation (...) and categorization of objects. Two types of category learning should be distinguished. Fixed space category learning occurs when new categorizations are representable with the available feature set. Flexible space category learning occurs when new categorizations cannot be represented with the features available. Whether fixed or flexible, learning depends on the featural contrasts and similarities between the new category to be represented and the individual's existing concepts. Fixed feature approaches face one of two problems with tasks that call for new features: If the fixed features are fairly high level and directly useful for categorization, then they will not be flexible enough to represent all objects that might be relevant for a new task. If the fixed features are small, subsymbolic fragments (such as pixels), then regularities at the level of the functional features required to accomplish categorizations will not be captured by these primitives. We present evidence of flexible perceptual changes arising from category learning and theoretical arguments for the importance of this flexibility. We describe conditions that promote feature creation and argue against interpreting them in terms of fixed features. Finally, we discuss the implications of functional features for object categorization, conceptual development, chunking, constructive induction, and formal models of dimensionality reduction. Key Words: concept learning; conceptual development; features; perceptual learning; stimulus encoding. (shrink)

Analyses of dispositional ascriptions in terms of conditional statements famously confront the problems of finks and masks. We argue that conditional analyses of dispositions, even those tailored to avoid finks and masks, face five further problems. These are the problems of: (i) Achilles' heels, (ii) accidental closeness, (iii) comparatives, (iv) explaining context sensitivity, and (v) absent stimulus conditions. We conclude by offering a proposal that avoids all seven of these problems.