Switching of response modalities

When participants perform a sequence of different tasks, it is assumed that the engagement in one task leads to the inhibition of the previous task. This inhibition persists and impairs performance when participants switch back to this (still inhibited) task after only one intermediate trial. Previous task-switching studies on this issue have defined different tasks at the level of stimulus categorization. In our experiments we used different response modalities to define tasks. Participants always used the same stimulus categorization (e.g., categorize a digit as odd vs. even), but had to give a vocal, finger, or foot response (A, B, or C). Our results showed a higher reaction time and error rate in ABA sequences than in CBA sequences, indicating n - 2 repetition cost as a marker for persisting task inhibition. We assume that different response modalities can define a task and are inhibited in a “task switch” in the same way as stimulus categories are inhibited.     

Freudian modalities of disbelief

This article can be characterized as a ‘rediscovery’ of a notion of psychoanalysis that had disappeared or had been confused by later operations. The authors explore a Freudian notion that has been unjustly misunderstood, especially because of the multiple ways in which ‘Unglaube’ – disbelief – has been translated. We shall establish the archaeology of this term in Freud by extracting its three significant modes. Firstly, paranoiac disbelief designates an unconscious process of the rejection of belief in the subject's first encounter with a sexual reality that is always traumatic. Secondly, the obsessional neurotic's disbelief, which we shall call ‘incredulity’, is a secondary, less radical refusal of belief, one that is different from its paranoiac counterpart. Finally, we shall envision a third – dialectical – type of disbelief, which Freud called ‘act of disbelief’ and which will enable us to approach the fundamental epistemic and ethical stakes for psychoanalysis.     

Graded modalities. I

We study a modal system ¯T, that extends the classical (prepositional) modal system T and whose language is provided with modal operators M inn (nN) to be interpreted, in the usual kripkean semantics, as there are more than n accessible worlds such that.... We find reasonable axioms for ¯T and we prove for it completeness, compactness and decidability theorems.The authors are very indebted to the referee for Ms consideration and appreciation of their work.     

Spatial ontology and physical modalities

Conclusion Most relational theories assert both that spatial discourse is reducible to talk about physical objects and their spatial relations, and that the relation of congruence derives from a non-metrical relation which intervals bear or possibly bear to measuring instruments. We have shown that there are serious logical difficulties involved in maintaining both these positions and the thesis of the continuity of space. We have also shown that Grünbaum's motivating argument for the reduction of congruence is unsound, and, moreover, that the prospects of formulating the kind of definition which this reduction requires seem to rest upon a wholly vague notion of physical possibility. Alternatively, if congruence is taken as primitive, it seems plausible that spatial discourse can be reconstructed so that there is no ontological commitment to spatial objects other than physical objects. Whether or not this relational thesis is ultimately defensible requires more elaboration of the relational theory, and investigation of its role in the formalizations of current physical theories. It is odd, considering the wide currency of relational theories, that this work has never been done.Preparation of this paper was supported in part by a grant from the National Science Foundation (Grant No. SOC75-08464) to the first author.     

Temporal-order judgments and reaction time for stimuli of different modalities

Summary Reaction times and the relative latency evaluated by the temporal-order-judgment method for two stimuli of different modalities (visual and auditory) were measured. The difference between reaction times for visual and auditory stimuli was about 40 ms. The relative latency was slightly shorter, however; in conflict with Rutschmann and Link's (1964) previous result, the auditory stimulus must be delayed to be perceived simultaneously with the visual one.     

Switching attention between modalities: further evidence for visual dominance

The present study examined cross-modal selective attention using a task-switching paradigm. In a series of experiments, we presented lateralized visual and auditory stimuli simultaneously and asked participants to make a spatial decision according to either the visual or the auditory stimulus. We observed consistent cross-modal interference in the form of a spatial congruence effect. This effect was asymmetrical, with higher costs when responding to auditory than to visual stimuli. Furthermore, we found stimulus-modality-shift costs, indicating a persisting attentional bias towards the attended stimulus modality. We discuss our findings with respect to visual dominance, directed-attention accounts, and the modality-appropriateness hypothesis.     

Attentional orienting across the sensory modalities

This event-related potential study investigated (i) to what extent incongruence between attention-directing cue and cued target modality affects attentional control processes that bias the system in advance to favor a particular stimulus modality and (ii) to what extent top-down attentional control mechanisms are generalized for the type of information that is to be attended. To this end, both visual and auditory word cues were used to instruct participants to direct attention to a specific visual (color) or auditory (pitch) stimulus feature of a forthcoming multisensory target stimulus. Effects of cue congruency were observed within 200 ms post-cue over frontal scalp regions and related to processes involved in shifting attention from the cue modality to the modality of the task-relevant target feature. Both directing visual attention and directing auditory attention were associated with dorsal posterior positivity, followed by sustained fronto-central negativity. However, this fronto-central negativity appeared to have an earlier onset and was more pronounced when the visual modality was cued. Together the present results suggest that the mechanisms involved in deploying attention are to some extent determined by the modality (visual, auditory) in which attention operates, and in addition, that some of these mechanisms can also be affected by cue congruency.     

Restricted attentional capacity between sensory modalities

The purpose of the experiments was to demonstrate an attentional-blink (AB) effect in a visual second task following the processing of a simple auditory signal. Subjects monitored a stream of letters presented at the middle of a computer screen using rapid serial visual presentation for the presence of a visual target (an X or a Y). In experimental trials, the visual target followed a pure tone that required an immediate speeded-choice response. When the tone had to be processed, accuracy in the visualencoding task suffered a marked and prolonged deficit that was timelocked to the onset of the tone. When the tone could be ignored or when no tone was presented, no deficit was observed in the visual task. The results demonstrate a cross-modal AB effect produced by a simple two-choice auditory discrimination task. The results are consistent with the view that at least part of the AB effect has a central, amodal, postperceptual locus.     

Normal predicative logics with graded modalities

In this work we extend results from [4], [3] and [2] about propositional calculi with graded modalities to the predicative level. Our semantic is based on Kripke models with a single domain of interpretation for all the worlds. Therefore the axiomatic system will need a suitable generalization of the Barcan formula. We haven't considered semantics with world-relative domains because they don't present any new difficulties with respect to classical case. Our language will have, as in [1], constant and function symbols, but they will have a rigid interpretation. In this instance the terms will be considered rigid designators, that is, their interpretations will be the same in all possible worlds (cfr. [5]). Nevertheless we will not consider languages with identity: in this way we avoid the problems of identity in modal contexts. On the other hand, we think that in that context would arise essentially the same problems which occur in classical predicative modal logic. Finally we will consider only denumerable languages because the extension to non denumerable ones isn't conceptually problematic.The present work was carried out under a grant of the Foundation U. Bordoni.     

Bi-Heyting algebras,toposes and modalities

The aim of this paper is to introduce a new approach to the modal operators of necessity and possibility. This approach is based on the existence of two negations in certain lattices that we call bi-Heyting algebras. Modal operators are obtained by iterating certain combinations of these negations and going to the limit. Examples of these operators are given by means of graphs.