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)

There are many ways to assess face perception skills. In this study, we describe a novel task battery FEAST (Facial Expression Action Stimulus Test) developed to test recognition of identity and expressions of human faces as well as stimulus control categories. The FEAST consists of a neutral and emotional face memory task, a face and object identity matching task, a face and house part-to-whole matching task, and a human and animal facial expression matching task. The identity and part-to-whole (...) matching tasks contain both upright and inverted conditions. The results provide reference data of a healthy sample of controls in two age groups for future users of the FEAST. (shrink)

Among Pylyshyn's most important questions is determining the boundaries of early vision. A simple stimulus illustrates that, in addition to the dominant percept, most observers can perceive alternative interpretations of 3-D surface layout only after provided with suggestions. These observations may indicate that cognitive influences reach the stages of visual processing where 3-D surface configurations are resolved.

This paper explores the implications of some experimental data for views that identify colors with objective physical properties such as reflectance profiles. Those who reject objectivist views often argue from the existence of intersubjective differences in color categorization ; but objectivists have managed to stand their ground by identifying colors with sets or ranges of reflectances individuated by the ways in which they stimulate the visual system. In the interest of moving the debate forward, I provide a new kind of (...) evidence against objectivism. Results of a psycholinguistic experiment reveal hysteresis and enhanced contrast in ordinary speakers’ applications of vague terms. These dynamical patterns are purely psychological and give rise to intra-subjective variation in subjects’ applications of vague predicates; in particular, in the case of color predicates, nothing in the stimulus configuration or the illuminant undergoes any change, the only variable being the order in which stimuli are judged. I hypothesize that these order effects are necessary if vague words are to be applicable to values on dimensions, like color, that admit of continuous change. To the extent that this hypothesis is correct, it suggests that if colors are the properties named by ordinary color predicates, and ordinary color predicates are vague, and the application of vague predicates exhibits the order effects found in the experiment, colours cannot be physical or otherwise objective in nature. (shrink)

A collection of experimental papers focusing on problems of visual perception treated from a transactional viewpoint where "the perceiving mechanism and the stimulus configuration are merely integrally related parts, and in which the assumptions, needs, values and purposes of the perceiver are equally important." Though some of the general conclusions drawn do not seem fully warranted, the experiments themselves are fascinating, showing the varied factors influencing perception. --R. J. B.

A configuration of infantile attributes including a large head, large eyes, with a small nose and mouth low on the head comprise the visual baby schema or Kindchenschema that English speakers call “cute.” In contrast to the stimulus gestalt that evokes it, the evoked emotional response to cuteness has been little studied, perhaps because the emotion has no specific name in English, Norwegian, or German. We hypothesize that cuteness typically evokes kama muta, a social-relational emotion that in other (...) contexts is often labeled in English as being moved or touched, heartwarming, nostalgia, patriotic feeling, being touched by the Spirit, the feels, etcetera. What evokes kama muta is sudden intensification of a communal sharing relationship, either communal sharing between the person and another, or communal sharing between observed others. In accord with kama muta theory, we hypothesize that a kama muta response to cuteness results from a sudden feeling of communal sharing with the cute target. In colloquial terms, the perceiver adores the cute kittens and their heart goes out to them. When a person perceives cute targets interacting affectionately - that is, intensifying communal sharing between them - this should strengthen a kama muta response. We experimentally investigated these predictions in two studies (N = 356). Study 1 revealed that videos of cute targets evoked significantly more kama muta than videos of targets that were not particularly cute. Study 2, pre-registered, found that, as hypothesized, when cute targets interacted affectionately they evoked more kama muta and were humanized more than when they were not interacting. We measured the level of kama muta by self-reports of sensations and signs and of feelings labelled heartwarming, being moved, and being touched. Participants' ratings of kama muta were positively correlated with reported cuteness. In addition, as in our previous research on kama muta elicited by other types of stimuli, trait empathic concern predicted kama muta responses and perceived cuteness. The studies thus provide first evidence that cute stimuli evoke the heartwarming emotion of kama muta. (shrink)

Several forms of dietary learning have been identified in humans. These include flavor–flavor learning, flavor–postingestive learning , and learned satiety. Generally, learning is thought to occur in the absence of contingency or demand awareness. However, a review of the literature suggests that this conclusion may be premature because measures of awareness lack the rigor that is found in studies of other kinds of human learning. If associations do configure outside awareness then this should be regarded as a rare instance of (...) automatic learning. Conversely, if awareness is important, then successful learning may be governed by an individual’s beliefs and predilection to attend to stimulus relationships. For researchers of dietary learning this could be critical because it might explain why learning paradigms have a reputation for being unreliable. Since most food preferences are learned, asking questions about awareness can also tell us something fundamental about everyday dietary control. (shrink)

Experiments are presented showing that visual search for Mueller-Lyer (ML) stimuli is based on complete configurations, rather than component segments. Segments easily detected in isolation were difficult to detect when embedded in a configuration, indicating preemption by low-level groups. This preemption—which caused stimulus components to become inaccessible to rapid search—was an all-or-nothing effect, and so could serve as a powerful test of grouping. It is shown that these effects are unlikely to be due to blurring by simple spatial (...) filters at early visual levels. It is proposed instead that they are due to more sophisticated processes that rapidly bind contour fragments into spatially-extended assemblies. These results support the view that rapid visual search cannot access the primitives formed at the earliest stages of visual processing; rather, it can access only higher-level, more ecologically-relevant structures. (shrink)

We show that true colors as defined by Chevreul (1839) produce unsuspected simultaneous brightness induction effects on their immediate grey backgrounds when these are placed on a darker (black) general background surrounding two spatially separated configurations. Assimilation and apparent contrast may occur in one and the same stimulus display. We examined the possible link between these effects and the perceived depth of the color patterns which induce them as a function of their luminance contrast. Patterns of square-shaped inducers of (...) a single color (red, green, blue, yellow, or grey) were placed on background fields of a lighter and a darker grey, presented on a darker screen. Inducers were always darker on one side of the display and brighter on the other in a given trial. The intensity of the grey backgrounds varied between trials only. This permitted generating four inducer luminance contrasts, presented in random order, for each color. Background fields were either spatially separated or consisted of a single grey field on the black screen. Experiments were run under three environmental conditions: dark-adaptation, daylight, and rod-saturation after exposure to bright light. In a first task, we measured probabilities of contrast, assimilation, and no effect in a three-alternative forced-choice procedure (background appears brighter on the ‘left’, on the ‘right’ or the ‘same’). Visual adaptation and inducer contrast had no significant influence on the induction effects produced by colored inducers. Achromatic inducers produced significantly stronger contrast effects after dark-adaptation, and significantly stronger assimilation in daylight conditions. Grouping two backgrounds into a single one was found to significantly decrease probabilities of apparent contrast. Under the same conditions, we measured probabilities of the inducers to be perceived as nearer to the observer inducers. These, as predicted by Chevreul’s law of contrast, were determined by the luminance contrast of the inducers only, with significantly higher probabilities of brighter inducers to be seen as nearer, and a marked asymmetry between effects produced by inducers of opposite sign. Implications of these findings for theories which attempt to link simultaneous induction effects to the relative depth of object surfaces in the visual field are discussed. (shrink)

Recent theories of cognition have argued that embodied experience is important for conceptual processing. Embodiment can be contrasted with linguistic factors such as the typical order in which words appear in language. Here, we report four experiments that investigated the conditions under which embodiment and linguistic factors determine performance. Participants made speeded judgments about whether pairs of words or pictures were semantically related or had an iconic relationship. The embodiment factor was operationalized as the degree to which stimulus pairs (...) were presented in the spatial configurations in which they usually occur (i.e., an iconic configuration, e.g., attic presented above basement). The linguistic factor was operationalized as the frequency of the stimulus pairs in language. The embodiment factor predicted error rates and response time better for pictures, whereas the linguistic factor predicted error rates and response time better for words. These findings were modified by task, with the embodiment factor being strongest in iconicity judgments for pictures and the linguistic factor being strongest in semantic judgments for words. Both factors predicted error rates and response time for both semantic and iconicity judgments. These findings support the view that conceptual processing is both linguistic and embodied, with a bias for the embodiment or the linguistic factor depending on the nature of the task and the stimuli. (shrink)

This article argues that rapid eye movement (REM) dreaming is elaborative encoding for episodic memories. Elaborative encoding in REM can, at least partially, be understood through ancient art of memory (AAOM) principles: visualization, bizarre association, organization, narration, embodiment, and location. These principles render recent memories more distinctive through novel and meaningful association with emotionally salient, remote memories. The AAOM optimizes memory performance, suggesting that its principles may predict aspects of how episodic memory is configured in the brain. Integration and segregation (...) are fundamental organizing principles in the cerebral cortex. Episodic memory networks interconnect profusely within the cortex, creating omnidirectional “landmark” junctions. Memories may be integrated at junctions but segregated along connecting network paths that meet at junctions. Episodic junctions may be instantiated during non–rapid eye movement (NREM) sleep after hippocampal associational function during REM dreams. Hippocampal association involves relating, binding, and integrating episodic memories into a mnemonic compositional whole. This often bizarre, composite image has not been present to the senses; it is not “real” because it hyperassociates several memories. During REM sleep, on the phenomenological level, this composite image is experienced as a dream scene. A dream scene may be instantiated as omnidirectional neocortical junction and retained by the hippocampus as an index. On episodic memory retrieval, an external stimulus (or an internal representation) is matched by the hippocampus against its indices. One or more indices then reference the relevant neocortical junctions from which episodic memories can be retrieved. Episodic junctions reach a processing (rather than conscious) level during normal wake to enable retrieval. If this hypothesis is correct, the stuff of dreams is the stuff of memory. (shrink)

Luminance and color are strong and self-sufficient cues to pictorial depth in visual scenes and images. The present study investigates the conditions Under which luminance or color either strengthens or overrides geometric depth cues. We investigated how luminance contrasts associated with color contrast interact with relative height in the visual field, partial occlusion, and interposition in determining the probability that a given figure is perceived as ‘‘nearer’’ than another. Latencies of ‘‘near’’ responses were analyzed to test for effects of attentional (...) selection. Figures in a pair were supported by luminance contrast or isoluminant color contrast and combined with one of the three geometric cues. The results of Experiment 1 show that luminance contrasts associated with hue, when it does not interact with other hues, produces the same effects as achromatic luminance contrasts: The probability of‘‘near’’ increases with luminance contrast while the latencies for ‘‘near’’ responses decrease. Partial occlusion is found to be a strong enough pictorial cue to support a weaker red luminance contrast. Interposition cues lose out against cues of spatial position and partial occlusion. The results of Experiment 2, with isoluminant displays of varying color contrast, reveal that red color contrast on a light background supported by any of the three geometric cues wins over green or white supported by any of the three geometric cues. On a dark background, red color contrast supported by the interposition cue loses out against green or white color contrast supported by partial occlusion. These findings reveal that color is not an independent depth cue, but is strongly influenced by luminance contrast and stimulus geometry. Systematically shorter response latencies for stronger ‘‘near’’ percepts demonstrate that selective visual attention reliably detects the most likely depth cue combination in a given configuration. (shrink)

The concept of simultaneous masking in visual field is discussed, in the light of classical examples, of the various kinds of the phenomenon, of a modal completion, of the figure/ground phenomenon, of ambiguous and reversible figures, of mimicry and camouflage and eventually of the complexity of the stimulus. There is some reference to masking in auditory field. The “reality” of the masked configuration is discussed, drawing the conclusion that it is perceptually unreal. The fact that the masking phenomenon (...) cannot take place without comparison between two perceptual acts – what we see at one moment and what we see a moment after LATER – and the fact that the masked configuration pops out with some surprise, lead to the conclusion that simultaneous masking in visual field is not a bare perceptual phenomenon, but a psychological process not unlike insight. (shrink)

In recent years we have seen a dramatic shift, in several different areas of communication studies, from an information-theoretic to a dynamic systems paradigm. In an information processing system, communication, whether between cells, mammals, apes, or humans, is said to occur when one organism encodes information into a signal that is transmitted to another organism that decodes the signal. In a dynamic system, all of the elements are continuously interacting with and changing in respect to one another, and an aggregate (...) pattern emerges from this mutual co-action. Whereas the information-processing paradigm looks at communication as a linear, binary sequence of events, the dynamic systems paradigm looks at the relation between behaviors and how the whole configuration changes over time. One of the most dramatic examples of the significance of shifting from an information processing to a dynamic systems paradigm can be found in the debate over the interpretation of recent advances in ape language research (ALR). To some extent, many of the early ALR studies reinforced the stereotype that animal communication is functional and stimulus bound, precisely because they were based on an information-processing paradigm that promoted a static model of communicative development. But Savage-Rumbaugh's recent results with bonobos has introduced an entirely new dimension into this debate. Shifting the terms of the discussion from an information-processing to a dynamic systems paradigm not only highlights the striking differences between Savage-Rumbaugh's research and earlier ALR studies, but further, it sheds illuminating light on the factors that underpin the development of communication skills in great apes and humans, and the relationship between communicative development and the development of language. Key Words: apes; ape language research (ALR); brain development; co-regulation; communication; dynamic systems; language development; symbols. (shrink)

Group musical performance, especially large instrumental ensembles, present the outward appearance of an asymmetric, temporally immediate stimulus-response relationship between conductor and ensemble. Interestingly, anecdotal reports from both conductors and performers indicate a degree of variability in the timing of orchestral response to the conductor’s gestures. This observation is not present in anecdotal accounts of other instrumental ensemble settings, like wind bands, but commonplace occurrence among orchestral musicians indicates the potential presence of greater complexity in the observed relationship. This study (...) investigates both the quality and quantity of temporal lag between conductor and ensemble in two common instrumental ensemble configurations – wind bands and orchestras – in an effort to describe the interplay present within conducted group performance. The findings indicate that the anecdotally identified lag is present within all ensemble types, and that it presents a flexible, dynamic temporal relationship between conductor and ensemble. Additionally, both the quantity and quality of lag values are significantly different between ensemble types, experience levels, and musical content. Several avenues for future research are identified, and confounds within the sampled ensembles are examined for their potential roles in the observed relationships. (shrink)

Linguistic and non-linguistic pattern learning have been studied separately, but we argue for a comparative approach. Analogous inductive problems arise in phonological and visual pattern learning. Evidence from three experiments shows that human learners can solve them in analogous ways, and that human performance in both cases can be captured by the same models. We test GMECCS, an implementation of the Configural Cue Model in a Maximum Entropy phonotactic-learning framework with a single free parameter, against the alternative hypothesis that learners (...) seek featurally simple algebraic rules. We study the full typology of patterns introduced by Shepard, Hovland, and Jenkins (), instantiated as both phonotactic patterns and visual analogs, using unsupervised training. Unlike SHJ, Experiments 1 and 2 found that both phonotactic and visual patterns that depended on fewer features could be more difficult than those that depended on more features, as predicted by GMECCS but not by rule-seeking. GMECCS also correctly predicted performance differences between stimulus subclasses within each pattern. A third experiment tried supervised training to elicit simple rule-seeking phonotactic learning, but cue-based behavior persisted. We conclude that similar cue-based cognitive processes are available for phonological and visual concept learning, and hence that studying either kind of learning can lead to significant insights about the other. (shrink)

Background: Continuous viewing of ambiguous patterns is characterized by wavering perception that alternates between two or more equally valid visual solutions. However, when such patterns are viewed intermittently, either by repetitive presentation or by periodic closing of the eyes, perception can become locked or "frozen" in one configuration for several minutes at a time. One aspect of this stabilization is the possible existence of a perceptual memory that persists during periods in which the ambiguous stimulus is absent. Here, (...) we use a novel paradgim of temporally interleaved ambiguous stimuli to explore the nature of this memory, with particular regard to its potential impact on perceptual organization. Results: We found that the persistence of a perceptual configuration was robust to interposed visual patterns and, further, that at least three ambiguous patterns, when interleaved in time, could undergo parallel, stable time courses. Then, using an interleaved presentation paradigm, we established that the occasional reversal in one pattern could be coupled with that of its interleaved counterpart, and that this coupling was a function of the structural similarity between the patterns. Conclusions: We postulate that the stabilization observed with repetitive presentation of ambiguous patterns can be at least partially accounted for by processes that retain a recent perceptual interpretation, and we speculate that such memory may be important in natural vision. We further propose tha the interleaved paradigm introduced here may be of great value to gauge aspects of stimulus similarity that appeal to particular mechanisms of perceptual organization. (shrink)

Failure to take note of distinctive attributes in the distal stimulus leads to an inadequate proximal encoding. Representation of similarities in Chorus suffers in this regard. Distinctive qualities may require additional complex representation (e.g., reference to linguistic terms) in order to facilitate discrimination. Additional semantic information, which configures proximal attributes, permits accurate identification of true veridical stimuli.

La filosofía de Nietzsche anticipó notablemente el umbral de la modernidad biológica al conceptualizar el alcance fisiológico de la moral, la política y la religión, así como su instrumentalización con fines de control social. El objetivo de este artículo es analizar el estímulo que ha representado la filosofía de Nietzsche para algunos de los principales pensadores de la cuestión biopolítica, en concreto, Michel Foucault, Roberto Esposito y Peter Sloterdijk, y desvelar en qué medida sus núcleos conceptuales convergen y divergen. La (...) aportación concreta reside en señalar algunos de los vínculos que articulan el tema de la disciplina y la cría con la configuración de la biopolítica como una de las principales corrientes filosóficas actuales, analizar las interpretaciones que dichos pensadores han formulado sobre la cuestión de la Züchtung y resaltar así la capacidad heurística de la filosofía nietzscheana para el diagnóstico de nuestro presente. -/- Nietzsche notably anticipated the threshold of biological modernity, when he conceptualized the physiological scope of morals, politics and religion, as well as their instrumentalization with the aim of social control. The aim of this paper is to analyze the stimulus that Nietzsche’s philosophy has represented for some of the main philosophers of biopolitics, namely Michel Foucault, Roberto Esposito and Peter Sloterdijk, and to reveal to what extent their core concepts converge and diverge. The specific contribution is to point out some of the links between the theme of discipline and breeding (Zucht und Züchtung) and the configuration of biopolitics as one of the main philosophical currents, to analyze whether and how those philosophers have interpreted the question of Züchtung in Nietzsche’s philosophy, and to stress the heuristic capacity of Nietzschean philosophy for the diagnosis of current social issues. Keywords: Nietzsche; breeding; discipline; Foucault; biopower; norm; Esposito; community; Sloterdijk; anthropotechnics. (shrink)

It is hypothesised that threatening stimuli are detected better due to their salience or physical properties. However, these stimuli are typically embedded in a rich context, motivating the question whether threat detection is facilitated via learning of contexts in which threat stimuli appear. To address this question, we presented threatening face targets in new or old spatial configurations consisting of schematic faces and found that detection of threatening targets was faster in old configurations. This indicates that individuals are able to (...) learn regularities within visual contexts and use this contextual information to guide detection of threatening targets. Next, we presented threatening and non-threatening face targets embedded in new or old spatial configurations. Detection of threatening targets was facilitated in old configurations, and this effect was reversed for non-threatening targets. Present findings show that detection of threatening targets is driven not only by stimulus properties as theorised traditionally but also by learning of contexts in which threatening stimuli appear. Further, results show that context learning for threatening targets obstructs context learning for non-threatening targets. Overall, in addition to typically emphasised bottom-up factors, our findings highlight the importance of top-down factors such as context and learning in detection of salient, threatening stimuli. (shrink)

Human articulated motion can be readily recognized robustly even from impoverished so-called point-light displays. Such sequence information is processed by separate visual processing channels recruiting different stages at low and intermediate levels of the cortical visual processing hierarchy. The different contributions that motion and form information make to form articulated, or biological, motion perception are still under investigation. Here we investigate experimentally whether and how specific spatio-temporal features, such as extrema in the motion energy or maximum limb expansion, indicated by (...) the lateral and longitudinal extension, constrain the formation of the representations of articulated body motion. In order to isolate the relevant stimulus properties we suggest a novel masking technique, which allows to selectively impair the ankle information of the body configuration while keeping the motion of the point-light locations intact. Our results provide evidence that maxima in feature channel representations, e.g., the lateral or longitudinal extension, define elemental features to specify key poses of biological motion patterns. These findings provide support for models which aim at automatically building visual representations for the cortical processing of articulated motion by identifying temporally localized events in a continuous input stream. (shrink)

By hypothesis, awareness is involved in the modulation of feedback from semantics to the lexical level in the visual word recognition system. When subjects are aware of the fact that there are many related prime–target pairs in a semantic priming experiment, this knowledge is used to configure the system to feed activation back from semantics to the lexical level so as to facilitate processing. When subjects are unaware of this fact, the default set is maintained in which activation is not (...) fed back from semantics to the lexical level so as to conserve limited resources. Qualitative differences in the pattern of data from two lexical decision experiments that employ masked priming are consistent with this hypothesis. Semantic context and stimulus quality interact when the prime is processed with awareness whereas these same two factors produce additive effects on RT when the prime is unlikely to have been processed with awareness. These experiments thus illustrate one way in which awareness affects the dynamics of visual word recognition. (shrink)

Perceived size is a function of viewing distance, retinal images size, and various contextual cues such as linear perspective and the size and location of neighboring objects. Recently, we demonstrated that illusion magnitudes of classic visual size illusions may be greatly enhanced or reduced by adding dynamic elements. Specifically, a dynamic version of the Ebbinghaus illusion (classically considered a “size contrast” illusion) led to a greatly enhanced illusory effect, whereas a dynamic version of the Corridor illusion (a “size constancy” illusion) (...) led to a greatly diminished illusory effect. Although these differences may arise from the different processes underlying these illusions (size contrast vs. size constancy), the dynamic variants we tested in our previous work also differed in the nature of the dynamic elements; specifically, whereas the Dynamic Ebbinghaus included a moving target and inducers that changed size and position, the Dynamic Corridor only included a moving target on a static background. Here, we explore further dynamic versions of the Ebbinghaus illusion and the Corridor and Ponzo illusions by separately manipulating three types of dynamic elements: target motion, context translation, and dynamic changes in context. Across five experiments examining 21 dynamic illusory configurations, adding target motion or a dynamically changing context separately resulted in little-to-no illusory effect. In contrast, the combination of target motion and a dynamically changing context led to a robust size illusion, consistent with an interactive effect. However, illusory effects that exceeded the matched classic, static illusory configuration were only observed for the dynamic versions of the Ebbinghaus illusion and the Revealed Ponzo illusions, in which the contextual elements changed size. We conclude that the combination of target motion and a dynamically changing context are necessary to produce dynamic size illusions, but that enhancement above and beyond static illusions may be largely specific to size contrast effects. Our results have important implications for the integration of motion signals, a ubiquitous environmental stimulus, in the perception of object size. (shrink)

The concept of simultaneous masking in visual field is discussed, in the light of classical examples, of the various kinds of the phenomenon, of a modal completion, of the figure/ground phenomenon, of ambiguous and reversible figures, of mimicry and camouflage and eventually of the complexity of the stimulus. There is some reference to masking in auditory field. The “reality” of the masked configuration is discussed, drawing the conclusion that it is perceptually unreal. The fact that the masking phenomenon (...) cannot take place without comparison between two perceptual acts – what we see at one moment and what we see a moment after LATER – and the fact that the masked configuration pops out with some surprise, lead to the conclusion that simultaneous masking in visual field is not a bare perceptual phenomenon, but a psychological process not unlike insight. (shrink)

Emotion recognition plays an important role in children’s socio-emotional development. Research on children’s emotion recognition has heavily relied on stimulus sets of photos of adults posed stereotyped facial configurations. The Child Affective Facial Expression set is a relatively new stimulus set that provides researchers with photographs of a diverse group of children’s facial configurations in seven emotional categories—angry, sad, happy, fearful, disgusted, surprised, and neutral. However, the large size of the full CAFE set makes it less ideal for (...) research in children. Here, we introduce two subsets of CAFE with 140 photographs of children’s facial configurations in each set, diverse in the race and ethnicity of the models, and designed to produce variability in naïve observers. The subsets have been validated with 1000 adult participants. (shrink)

Empirical evidence from both utility and psychophysical experiments suggests that people respond quite differently—perhaps discontinuously—to stimulus pairs when one consequence or signal is set to `zero.' Such stimuli are called unitary. The author's earlier theories assumed otherwise. In particular, the key property of segregation relating gambles and joint receipts (or presentations) involves unitary stimuli. Also, the representation of unitary stimuli was assumed to be separable (i.e., multiplicative). The theories developed here do not invoke separability. Four general cases based on (...) two distinctions are explored. The first distinction is between commutative joint receipts, which are relevant to utility, and the non-commutative ones, which are relevant to psychophysics. The second distinction concerns how stimuli of the form (x, C; y) and the operation of joint receipt are linked: by segregation, which mixes stimuli and unitary ones, and by distributivity, which does not involve any unitary stimuli. A class of representations more general than rank-dependent utility (RDU) is found in which monotonic functions of increments U(x)-U(y), where U is an order preseving representation of gambles, and joint receipt play a role. This form and its natural generalization to gambles with n > 2 consequences, which is also axiomatized, appear to encompass models of configural weights and decision affect. When joint receipts are not commutative, somewhat similar representations of stimuli arise, and joint receipts are shown to have a conjoint additive representation and in some cases a constant bias independent of signal intensity is predicted. (shrink)

In the present study, we have demonstrated hysteresis phenomena in the excitability of single, enzymatically dissociated guinea pig ventricular myocytes. Membrane potentials were recorded with patch pipettes in the whole-cell current clamp configuration. Repetitive stimulation with depolarizing current pulses of constant cycle length and duration but varying strength led to predictable excitation (1:l) and non-excitation (1:0) patterns depending on current strength. In addition, transition between patterns depended on the direction of current intensity change and stable hysteresis loops were obtained (...) in stimulus:response pattern vs. current intensity plots in 14 cells. Increase of pulse duration and decrease of stimulation rate contributed to a reduction in hysteresis loop areas. Changes in amplitude and shape of the subthreshold responses during the transitions from one stable pattern to the other, suggested that activity led to an increase in membrane resistance, particularly in the voltage domain between resting potential, and threshold. Therefore, we modelled the dynamic behaviour of the single cells as a function of diastolic membrane resistance, using previously published analytical solutions. Numerical iteration of the analytical model equations closely reproduced the experimental hysteresis loops in both qualitative and quantitative ways. In particular, the effect of stimulation frequency on the model was similar to the experimental findings. The overall study suggests that the excitability pattern of guinea pig ventricular myocytes accounts for hysteresis and bistabilities when current intensity is allowed to fluctuate around threshold levels. (shrink)

For the faithful there is much to ponder. In this short book, based on lectures delivered in Spain in 1990, Quine begins by locating his work historically.

W. V. Quine is one of the most eminent philosophers alive today. Now in his mid-eighties he has produced a sharp, sprightly book that encapsulates the whole of his philosophical enterprise, including his thinking on all the key components of his epistemological stance--especially the value of logic and mathematics. New readers of Quine may have to go slowly, fathoming for themselves the richness that past readers already know lies between these elegant lines. For the faithful there is much to ponder. (...) In this short book, based on lectures delivered in Spain in 1990, Quine begins by locating his work historically. He provides a lightning tour of the history of philosophy (particularly the history of epistemology), beginning with Plato and culminating in an appreciative sketch of Carnap's philosophical ambitions and achievements. This leads, in the second chapter, to an introduction to Quine's attempt to naturalize epistemology, which emphasizes his continuities with Carnap rather than the differences between them. The next chapters develop the naturalistic story of the development of science to take account of how our conceptual apparatus is enhanced so that we can view the world as containing re-identifiable objects. Having explained the role of observation sentences in providing a checkpoint for assessing scientific theories, and having despaired of constructing an empirical criterion to determine which sentences are meaningful, Quine in the remaining chapters takes up a variety of important issues about knowledge. He concludes with an extended treatment of his views about reference and meaning and his attitudes toward psychological and modal notions. The presentation is distinctive, and the many small refinements of detail and formulation will fascinate all who know Quine's philosophy. (shrink)

How can we make complexity work as part of a programme of engaged social science? This article attempts to answer that question by arguing that one way to do this is through a reconstruction of a central tool of a distinctively social science – the comparative method – understood as a procedure for elucidating the complex and multiple systems of causation that generate particular trajectories towards a desired future from the multiple sets of available futures. The article distinguishes between ‘simplistic (...) complexity’ and ‘complex complexity’. ‘Simplistic complexity’ seeks to explain emergence in complex systems as the product of simple rules and defines complex science as the process of establishing such rules. It can and does serve as the basis of technocratic social engineering in the interest of the powerful. In contrast ‘complex complexity’ recognizes the significance of social structure and willed social agency and does not reduce emergence to the mere working out of a restricted set of rules. Research programmes informed by this second approach must necessarily engage with social actors in context – they must be dialogical. This opens up the possibility of ‘complex complexity’ as a frame of reference for action-research directed towards the transformation of complex social systems. Comparative methods, and in particular Ragin’s qualitative comparative analysis approach, when deployed as part of such a programme, can provide meaningful information about the range of possible futures and the different configurations of causes which might generate particular desired social outcomes. (shrink)