Orientation perception in Williams Syndrome: Discrimination and integration

Williams Syndrome (WS) is a rare neurodevelopmental disorder, which stems from a genetic deletion on chromosome 7 and causes a profound weakness in visuospatial cognition. Our current study explores how orientation perception may contribute to the visuospatial deficits in WS. In Experiment 1, we found that WS individuals and normal 3–4 year olds had similar orientation discrimination thresholds and had similar prevalence of mirror-reversal errors for diagonal targets (±45 deg). In Experiment 2, we asked whether this immaturity in orientation discrimination would also be reflected in a task requiring integration of oriented elements. We found that sensitivities of WS individuals for detecting orientation-defined contours were higher than sensitivities of normal 3–4 year olds, and were not significantly different from sensitivities of normal adults. Together, these results suggest that orientation discrimination and orientation integration have different maturational trajectories in normal development and different susceptibilities to damage in WS. These may reflect largely separate visuospatial mechanisms.     

Perception with compensatory devices: from sensory substitution to sensorimotor extension

Sensory substitution devices provide through an unusual sensory modality (the substituting modality, e.g., audition) access to features of the world that are normally accessed through another sensory modality (the substituted modality, e.g., vision). In this article, we address the question of which sensory modality the acquired perception belongs to. We have recourse to the four traditional criteria that have been used to define sensory modalities: sensory organ, stimuli, properties, and qualitative experience ( Grice, 1962 ), to which we have added the criteria of behavioral equivalence ( Morgan, 1977 ), dedication ( Keeley, 2002 ), and sensorimotor equivalence ( O'Regan & Noë, 2001 ). We discuss which of them are fulfilled by perception through sensory substitution devices and whether this favors the view that perception belongs to the substituting or to the substituted modality. Though the application of a number of criteria might be taken to point to the conclusion that perception with a sensory substitution device belongs to the substituted modality, we argue that the evidence leads to an alternative view on sensory substitution. According to this view, the experience after sensory substitution is a transformation, extension, or augmentation of our perceptual capacities, rather than being something equivalent or reducible to an already existing sensory modality. We develop this view by comparing sensory substitution devices to other "mind-enhancing tools" such as pen and paper, sketchpads, or calculators. An analysis of sensory substitution in terms of mind-enhancing tools unveils it as a thoroughly transforming perceptual experience and as giving rise to a novel form of perceptual interaction with the environment.     

Nature versus nurture: The simple contrast

We respond to the commentary of Franklin, Wright, and Davies (Journal of Experimental Child Psychology,102, 239-245 [2009]) by returning to the simple contrast between nature and nurture. We find no evidence from the toddler data that makes us revise our ideas that color categories are learned and never innate.     

抑制控制能力衰退对知觉组织老年化的影响

通过比较注意线索对老年人和年轻人共线性和相似性知觉组织的影响,探讨了知觉组织老年化的原因。研究发现,注意线索对年轻人的助益更大,对老年人的助益较小,符合抑制控制理论的研究假设,同时本文还对加工速度、基本感觉能力等可能引起认知老年化的因素进行了分析。此外,还发现了知觉组织中与阅读习惯一致的方向偏好,无论在有无注意线索的条件下,135°方向上的知觉组织都快于45°方向上的知觉组织。     

Perceptual interactions in a minimalist virtual environment

How in real-life or through the use of technical devices can we recognize the presence of other persons and under what conditions can we differentiate them from objects? In order to approach this question, in the study reported here we explored the most basic conditions necessary for participants to recognize the presence of another person during a perceptual interaction. We created a mini-network of two minimalist devices and investigated whether participants were able to differentiate the perception of another person from the perception of a fixed and a mobile object even when the pattern of sensory stimulation was reduced to a bare minimum. We show that participants can recognize when the all-or-none tactile stimulation they experienced was attributable to an encounter with the other participant's avatar or the mobile object rather than with a fixed object. Participants were also able to establish different strategies in order to favor the situations of mutual perception. Thus, in the minimalist conditions of our experiment, the perception of another intentional subject was not based purely on any particular shape or objective trajectories of displacement; it was also based on properties that are intrinsic to the joint perceptual activity itself.     

Inattentional blindness for ignored words: Comparison of explicit and implicit memory tasks

Inattentional blindness is described as the failure to perceive a supra-threshold stimulus when attention is directed away from that stimulus. Based on performance on an explicit recognition memory test and concurrent functional imaging data Rees, Russell, Frith, and Driver [Rees, G., Russell, C., Frith, C. D., & Driver, J. (1999). Inattentional blindness versus inattentional amnesia for fixated but ignored words. Science, 286, 2504–2507] reported inattentional blindness for word stimuli that were fixated but ignored. The present study examined both explicit and implicit memory for fixated but ignored words using a selective-attention task in which overlapping picture/word stimuli were presented at fixation. No explicit awareness of the unattended words was apparent on a recognition memory test. Analysis of an implicit memory task, however, indicated that unattended words were perceived at a perceptual level. Thus, the selective-attention task did not result in perfect filtering as suggested by Rees et al. While there was no evidence of conscious perception, subjects were not blind to the implicit perceptual properties of fixated but ignored words.     

A Neo-Kantian foundation of Corporate Social Responsibility

‘Corporate Social Responsibility (CSR) is conceptualized in many ways. We argue that one cannot be indifferent about the issue of its conceptualization. In terms of methodology, our position is that any conceptual discussion must embed CSR in political theory. With regard to substance, we link up with the discussion on whether CSR must be defined on the basis of a tripartite or a quadripartite division of business responsibilities. We share A.B. Carroll’s intuition that a quadripartite division is called for as a basis to define CSR. However, defending the quadripartite division of business responsibilities requires that the distinctions between economic, legal, ethical and discretionary business responsibilities be made intelligible. Carroll’s account is defective in this respect. We argue that contemporary Neo-Kantian political ethics is able to make sense of these distinctions, because of its specific interpretation of liberalism. Interestingly, from a conventional liberal perspective this interpretation of liberalism is atypical, as it extends public morality beyond the domain of the law.

Local rather than global processing of visual arrays in numerosity discrimination by pigeons (Columba livia)

A series of experiments investigated which stimulus properties pigeons use when they discriminate pairs of visual arrays that differ in numerosity. Transfer tests with novel stimuli confirmed that the birds’ choices were based on relative differences in numerosity. However, pigeons differed from other species in the non-numerical cues that affected their choices. In human and non-human primates, numerical discrimination is often influenced by continuous variables such as surface area or overall stimulus brightness. Pigeons showed little evidence of using those cues, even when summed area and brightness had been correlated with numerosity differences and reward outcome. But when array-element sizes were asymmetrically distributed across numerosities, the birds readily utilized information about item sizes as an additional discriminative cue. These novel results are discussed in relation to pigeons’ tendency to focus on local, rather than global dimensions when they process other non-numerical complex visual stimuli. The findings suggest there may be inter-specific differences in the type of perceptual information that provides the input stage for mechanisms underlying numerical processing. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Stability of choices in a risky decision‐making task: a 3‐year longitudinal study with children and adults

In a 3‐year follow‐up to Levin and Hart's ( 2003 ) study, we observed the same children, now 9–11 years old, and their parents in the same risky decision‐making task. At the aggregate level the same pattern of means was observed across time periods. At the individual level the key variables were significantly correlated across time periods for both children and adults. Taken together with the results from the original study and earlier studies, these results solidify the following conclusions: children utilize both probability and outcome information in risky decision‐making; the tendency to make more risky choices to avoid a loss than to achieve a gain of equal magnitude, which is a major tenet of the leading theories of risky decision‐making, occurs for children as well as adults; children make more risky choices than adults; temperamental predictors of risky choice are valid for children as well as for adults. Copyright © 2006 John Wiley & Sons, Ltd.     

Vocal Features of Conversational Sarcasm: A Comparison of Methods

This study investigated vocal cues that differentiate sarcastic utterances from non-sarcastic utterances. Utterances were drawn from videotapes of participant interviews and arranged on a master tape for analysis. Utterances that were identified as sarcastic by speakers and recognized as sarcastic by listeners were randomly arranged with utterances identified and recognized as non-sarcastic by the same participants. Both sarcastic and non-sarcastic utterances were analyzed by two methods–acoustic analysis and perceptual coding. The acoustic analysis proved slightly more successful than the perceptual coding in discriminating between sarcastic and non-sarcastic utterances. The acoustic analysis indicated that fundamental frequency, frequency range, length of utterance, and total amount of sound significantly discriminated sarcastic from non-sarcastic utterances. The perceptual coding method revealed that pitch range, length of utterance, and total amount of sound significantly discriminated sarcastic from non-sarcastic utterances. Moderate correlations were found between the acoustic and perceptual variables.