Understanding Dali's Slave market with the disappearing bust of Voltaire: a case study in the scale information driving perception

A generic problem in vision is to know which information drives the perception of a stimulus. We address this problem in a case study that involves the perceptual reversal of an ambiguous image (here, Dali's painting the Slave Market with the Disappearing Bust of Voltaire 1940). In experiment 1, we use 'bubbles' (Gosselin and Schyns, 2001 Vision Research 41 2261-2271) to disambiguate the image and to determine the specific visual information that drives each possible perception (here, the nuns versus the bust of Voltaire). Experiment 2 validates that this information does determine the selective perception of the ambiguous image. We adapted the spatial-frequency channels of observers selectively to the information that mediates one of the two perceptions, to induce the opposite perception of the ambiguous image in a transfer phase. Together, the results suggest a method of revealing the visual information that drives perception.     

Memory for multidimensional source information

Source memory may comprise recollection of multiple features of the encoding episode. To analyze the simultaneous representation and retrieval of those multiple features, a multinomial memory model is presented that measures memory for crossed dimensions of source information. The first experiment investigated the validity of the new model. The model showed an excellent statistical fit to empirical data, and the parameters of multidimensional source memory were sensitive to manipulations of source similarity on distinct dimensions. The second experiment used the model to test the hypothesis that source memory for individual context attributes is stochastically related in the case of conscious recollection but independent in the case of familiarity-based recognition judgments. The prediction was supported by the introduction of a "remember"-"know" distinction in a multidimensional source memory test.     

Rapid adaptation to auditory-visual spatial disparity

The so-called ventriloquism aftereffect is a remarkable example of rapid adaptative changes in spatial localization caused by visual stimuli. After exposure to a consistent spatial disparity of auditory and visual stimuli, localization of sound sources is systematically shifted to correct for the deviation of the sound from visual positions during the previous adaptation period. In the present study, this aftereffect was induced by presenting, within 17 min, 1800 repetitive noise or pure-tone bursts in combination with synchronized, and 20° disparate flashing light spots, in total darkness. Post-adaptive sound localization, measured by a method of manual pointing, was significantly shifted 2.4° (noise), 3.1° (1 kHz tones), or 5.8° (4 kHz tones) compared with the pre-adaptation condition. There was no transfer across frequencies; that is, shifts in localization were insignificant when the frequencies used for adaptation and the post-adaptation localization test were different. It is hypothesized that these aftereffects may rely on shifts in neural representations of auditory space with respect to those of visual space, induced by intersensory spatial disparity, and may thus reflect a phenomenon of neural short-term plasticity.     

Place learning in scopolamine-treated rats: the roles of distal cues and catecholaminergic mediation

Experiments 1 and 2 tested the hypothesis that cholinergic receptor antagonists impair place learning in a water maze by interfering with the processing of distal, visual cues. Extramaze cues were offered to rats in the form of geometrical patterns arranged on the inner circumference of a curtain surrounding the water maze. In Experiment 1 the animals were offered both the distal cues and proximal cues in the form of pingpong balls in fixed positions on the surface of the water while only distal cues were present in Experiment 2. Animals were injected with either scopolamine (0.5 mg/kg body wt) or saline 20 min prior to the daily place learning sessions. Upon reaching criterion level performance the animals were tested on "rotation" sessions on which the distal cues were displaced. The outcome of such "rotations" demonstrated that-regardless of the presence or absence of proximal cues-scopolamine-treated rats relied at least as much as normal animals on the distal cues. The acquisition phase of both Experiments 1 and 2 demonstrated an almost complete lack of scopolamine-associated impairment in acquisition and performance of the place learning task. In Experiment 3 (when scopolamine was no longer administered) the subjects of Experiment 2 were exposed to a series of pharmacological "challenges" of their place learning performance and eventually to surgical ablation of the anteromedial prefrontal cortex. The outcome of the pharmacological challenges and the postoperative test of task performance demonstrated that the place learning performance of animals which had acquired the task under scopolamine was mediated by a neural substrate dissimilar to the substrate of task performance in normal animals. Rats acquiring the task while deprived of the cholinergic system demonstrated above-normal contributions to task mediation from catecholaminergic-probably dopaminergic-mechanisms and tentative results pointed to a "shift" toward prefrontal task mediation.     

RAP: a new framework for visual categorization

Cognitive science might almost be defined as several disciplines communicating their different perspectives on the mind, the common object of study. However, domain-specific concepts and techniques can prevent, rather than foster, a communication of viewpoints. In this article, we develop a new framework for visual categorization in which the interaction between Represented (R) information and Available (A) information determine the Potent (P) information (symbolically, R ? A approximately P). We argue and illustrate that this framework helps to establish a common language to articulate issues common to low-, mid-, and high-level vision. More importantly, we present new techniques with which to visualize the so-far elusive constructs of representation and potent information.     

The effects of approach and avoidance motor actions on the elements of creative insight

The authors propose that the nonaffective bodily feedback produced by arm flexion and extension informs individuals about the processing requirements of the situation, leading to the adoption of differential processing styles and thereby influencing creativity. Specifically, the authors predicted that arm flexion would elicit a heuristic processing strategy and bolster insight processes, whereas arm extension would elicit a systematic processing strategy and impair insight processes. To test these predictions, the authors assessed the effects of these motor actions on 3 central elements of creative insight: contextual set-breaking, restructuring, and mental search. As predicted, in 6 experiments, arm flexion, relative to arm extension, facilitated insight-related processes. In a 7th experiment, arm extension, relative to arm flexion, facilitated analytical reasoning, supporting a cognitive tuning interpretation of the findings.     

Attribution of aggression to acts: a four-factor model

Factors determining why acts are regarded as aggressive were investigated in a sample of 303 subjects (140 males, 163 females, M age = 17.7 yr., SD = 1.4). A model was tested, according to which people base their attribution of aggression to acts on four factors: (1) intention (yes/no), (2) reason (attack/defense), (3) injury (death/injury/no injury), and (4) mode (weapon/bare hands/nonphysical means). All four factors contributed to the explanation of attribution of aggression, and the order of importance was the one mentioned above, intention being most important. The interaction between intention and reason was the second most important, contributing more than reason alone. The findings are consistent with the severity of punishment in sentences for different crimes of violence.     

Money Doesn't Talk, It Swears: How Economic Stress and Resistance Resources Impact Inner-City Women's Depressive Mood

We examined the differential impact of chronic versus acute economic stress on depressive mood among a sample of 1241 low-income, single, European and African American women. Based on Hobfoll's (1988, 1989) conservation of resources (COR) theory, we predicted that acute resource loss would be more distressing than chronic economic lack. That is, although chronically impoverished conditions are stressful, the attendant resource losses created will be more distressing. We further predicted that mastery and social support would be more beneficial in offsetting the negative consequences of acute resource loss than the negative consequences of chronic economic lack, because acute loss creates identifiable demands that resources may address. Hence, we hypothesized that mastery and social support would show stress buffering effects only for material loss, not chronic lack. The findings generally supported the hypotheses, but mastery buffered only European American women's resource loss and social support buffered only African American women's resource loss. The findings are discussed in light of implications for prevention within theoretical and cultural contexts.     

Implicit and explicit learning of event sequences: evidence for distinct coding of perceptual and motor representations

Event-related brain potentials (ERPs) of 21 subjects were recorded in a choice reaction time task with a repeating eight-element long stimulus sequence. The regular event sequence was sometimes interrupted by 'perceptual' or by 'motor deviants' which both replaced an expected stimulus but either preserved or violated the sequence of motor responses. Response times confirmed that all subjects had acquired some knowledge of the sequential dependencies. By means of a post-experimental free recall and recognition test, subjects were classified as having either explicit or implicit knowledge of the event sequence. The ERPs showed different effects for different types of stimuli and the two groups. In the group of explicit learners, a larger N200 component was evoked by both types of deviants and a larger P300 by motor deviants only. In the group of implicit learners these 'perceptual components' remained unaffected. In contrast, in both groups of subjects the lateralized readiness potential (LRP) which accompanied motor deviants revealed a partial activation of the to be expected but incorrect response, i.e. motor learning. These results suggest that explicit learners acquire knowledge about both, stimulus and response dependencies while implicit learners acquire knowledge about response dependencies only.