Auditory-visual interaction and the timing of inputs

Summary The objective of this study was to analyze the structural properties of the respective inputs that are conducive to immediate auditory-visual cross-modal bias. The study was designed as an updated and extended replication of one by Thomas (1941). Subjects were presented with either auditory or visual target signals in several positions around the median plane, together with a competing signal, always in the other modality, 15° to the left or to the right of that plane. The task was to indicate whether the target signal came left or right of center. Target and competing signals were delivered according to three temporal configurations: continuously on for 4 s, or periodically interrupted at either a fast or a slow tempo, and all combinations of the three configurations were used. Judgements of the location of the auditory target signal were attracted toward the visual competing signal in all conditions but two, those with a periodic target signal and a continuous competing one. Conditions with the two signals in the same configuration yielded larger biases than those combining different configurations, confirming that synchronization of discordant inputs is a major condition of cross-modal interactions. The occurrence of significant bias in nonsynchronous conditions, on the other hand, suggests that another factor might be the attraction of localization responses by competing signals with salient temporal configurations, and that interruption might be one important source of saliency. Auditory biases of visual localization were, as usual, smaller than visual biases, but nevertheless reached significance in a majority of conditions, and were also influenced by timing in much the same way as the latter.This work was supported in part by the Belgian Fonds de la Recherche Fondamentale Collective (FRFC) under convention 2.4505.80. The first author is Chercheur qualifié of the Fonds National de la Recherche Scientifique (FNRS). The results have already been reported at the Symposium on Perception, Action and Development, Brussels, January 1984     

A novel automatic procedure for measuring ocular counterrolling: A computeranalytical method to determine the eye’s roll angle while subjects work on perceptual tasks

In investigations of the perception of space, the consideration of ocular counterrolling-the movement of the eye around its visual axis in response to body movement-is crucially important. The angle of this movement must be known in order for one to determine the precise retinal coordinates of a distal object. Following transformation, this stimulus serves as a reliable cue for visual direction. The otolith organs provide information about body tilt and are responsible for ocular counterrolling. A novel, noninvasive method to measure ocular counterrolling, based on the cross-correlation of digitized video pictures of the eyes, is presented. The resolution attained was ≤ 0.1°. The computer analysis is fully automatic and fast, and it can be performed while subjects work on perceptual tasks. No direct access to the eyeballs is required. Data from 4 subjects showing the counterrolling profile in various body positions are presented.     

Contrastive marking in French dialogue: Why and how

This experiment studies French-speaking adults' preferences for prosodic marking (focal accent) or morphosyntactic marking (clefting) to express information contrasts in dialogue. Our goal is to determine what syntactic and conceptual factors might contribute to these preferences, by examining for the former, the grammatical function of the item bearing the contrastive mark (subject vs complement) and, for the latter, the size of the class to which the contrasted item belongs (two members vs more than two members). The subjects' responses on a forced-choice judgment task showed that when only one device was used for contrast, subjects clearly preferred clefting for grammatical subjects and focal accent for complements. When both devices were used (prosodic and morphosyntactic), contrasted subjects were preferred over contrasted complements. Response times were longer when the contrasted item belonged to a two-member class. These results demonstrate that subjects' judgments of the suitability of linguistic devices for expressing information contrasts in French are more highly affected by syntactic factors than conceptual ones.     

Shifting Paradigms: Theorizing Care and Justice in Political Theory

The following is an introduction to a roundtable panel of the American Political Science Association meeting (Normative Political Theory Division) held September 2, 1994, in New York City. I set out some main themes in the “care/justice debate,” and suggest that the impasse between care proponents and liberal, neo-Kantian thinkers is perpetuated by caricatured construals of these theories; salient differences come into relief by addressing the ethical and political applications of these moral perspectives.     

Intuitionistic uniformity principles for propositions and some applications

This note deals with the prepositional uniformity principlep-UP: p x N A (p, x) x N p A (p, x) ( species of all propositions) in intuitionistic mathematics.p-UP is implied by WC and KS. But there are interestingp-UP-cases which require weak KS resp. WC only. UP for number species follows fromp-UP by extended bar-induction (ranging over propositions) and suitable weak continuity. As corollaries we have the disjunction property and the existential definability w.r.t. concrete objects. Other consequences are: there is no non-trivial countable partition of;id is the only injective function from to; there are no many-place injective prepositional functions; card () is incomparable with the cardinality of all metric spaces containing at least three elements.     

Integrating velocity,time, and distance information: A developmental study

The development of understanding the relationships between velocity, time, and distance was investigated in three tasks. In each task, values of two dimensions were given, and 5-year-olds, 10-year-olds, and adults had to infer values of the third dimension. These inferences were made in all age groups. The integration rules were found to depend upon age and task. In the distance = time × velocity task, all age groups obeyed the normative multiplication rule. In the time = distance ÷ velocity task, the two older age groups obeyed the normative division rule, but the 5-year-olds shifted to a simpler subtraction rule. In the velocity = distance ÷ time task, which was the most difficult, the two older age groups simplified to use of a subtraction rule, and the 5-year-olds simplified even further to use of a distance-only rule. The knowledge level revealed for young children contrasts sharply with results from previous studies using Piagetian choice tasks, which apparently investigate selective attention to one dimension rather than conceptual understanding of relations.