Recovery from object substitution masking induced by transient suppression of visual motion processing: a repetitive transcranial magnetic stimulation study

Object substitution masking is a form of visual backward masking in which a briefly presented target is rendered invisible by a lingering mask that is too sparse to produce lower image-level interference. Recent studies suggested the importance of an updating process in a higher object-level representation, which should rely on the processing of visual motion, in this masking. Repetitive transcranial magnetic stimulation (rTMS) was used to investigate whether functional suppression of motion processing would selectively reduce substitution masking. rTMS-induced transient functional disruption of cortical area V5/MT+, which is important for motion analysis, or V1, which is reciprocally connected with V5/MT+, produced recovery from masking, whereas sham stimulation did not. Furthermore, masking remained undiminished following rTMS over the region 2 cm posterior to V5/MT+, ruling out nonspecific effects of real stimulation and confirming regional specificity of the rTMS effect. The results suggest that object continuity via the normal function of the visual motion processing system might in part contribute to this masking. The relation of these findings to the reentrant processing view of object substitution masking and other visual phenomena is discussed.     

The Main Problem with USC Libertarianism

Libertarians like Robert Kane believe that indeterminism is necessaryfor free will. They think this in part because they hold both (1) thatmy being the ultimate cause of at least part of myself is necessary forfree will and (2) that indeterminism is necessary for this ``ultimateself-causation'. But seductive and intuitive as this ``USCLibertarianism' may sound, it is untenable. In the end, nometaphysically coherent (not to mention empirically valid) conception ofultimate self-causation is available. So the basic intuition motivatingthe USC Libertarian is ultimately impossible to fulfill.     

The Wind Chilled the Spectators, but the Wine Just Chilled: Sense, Structure, and Sentence Comprehension

Anticipation plays a role in language comprehension. In this article, we explore the extent to which verb sense influences expectations about upcoming structure. We focus on change of state verbs like shatter , which have different senses that are expressed in either transitive or intransitive structures, depending on the sense that is used. In two experiments we influence the interpretation of verb sense by manipulating the thematic fit of the grammatical subject as cause or affected entity for the verb, and test whether readers' expectations for a transitive or intransitive structure change as a result. This sense-biasing context influenced reading times in the postverbal regions. Reading times for transitive sentences were faster following good-cause than good-theme subjects, but the opposite pattern was found for intransitive sentences. We conclude that readers use sense-contingent subcategorization preferences during on-line comprehension.     

Attention shifts and the Simon effect: a failure to replicate Stoffer (1991)

The Simon effect refers to the intrusion of an irrelevant spatial dimension in the selection of a response to a stimulus. Recently, Stoffer (1991) proposed a specific role for attention orienting in the Simon effect. According to Stoffer, attentional shifts from an initial fixation point to a stimulus location are associated with the generation of a spatial code which specifies the position of the stimulus in relation to the last attended location. This spatial code forms the basis for the Simon effect because it is used to specify the selection of the right or left response. Three experiments were performed to examine further the attention-shift hypothesis forwarded by Stoffer. Experiment 1 was an attempt to replicate Stoffer (1991), but failed to do so. Experiments 2 and 3 were designed to optimize conditions for replicating crucial aspects of Stoffer's findings, but also failed to yield support for the attention-shift account.     

MONITORING CONSCIOUS RECOLLECTION VIA THE ELECTRICAL ACTIVITY OF THE BRAIN

Abstract— Although another person's experience of recollection cannot be observed directly, we have found that the underlying operations can be monitored using noninvasive electrophysiological techniques. Results from two experiments showed that brain potentials elicited 500 to 900 ms after the onset of visually presented words vary systematically in amplitude with manipulations that influence the extent to which subjects engage in recollective processing. These brain potentials can thus be construed as correlates of the subjective experience of recollection     

Strategic factors in a lexical-decision task: Evidence for automatic and attention-driven processes

The present study examined strategic factors in a semantic-priming, lexical-decision task. The first experiment demonstrated that the greater the proportion of related word-word pairs to unrelated word-word pairs, the greater the amount of facilitation, a result which is consistent with others reported in the literature. The second experiment demonstrated that this strategic factor apparently requires that sufficient time (at least several hundred milliseconds) be available for the processing of the priming word, and thus is probably caused by attention-driven processes. The third experiment replicated and extended the results of the first two studies by demonstrating that prime-target stimulus onset asynchrony is an important limiting factor in determining whether such proportion-induced strategic factors are involved in word-recognition processes, even when no other aspect or variable of the procedure changes. The results are discussed in the context of Posner and Snyder’s (1975a) two-process model of word recognition.     

SKED systems: Paper tape,Tennecomp, and OS/8

The SKED system has been developed at different levels of complexity and power for differing hardware configurations. The simplest of these, and the least expensive, is the paper-tape SKED system. Some of the drawbacks associated with the use of paper tape are absent in the Tennecomp magnetic tape cartridge system. Users with mass storage capabilities can make use of the OS/8 operating system (copyright DEC) to speed up all aspects of the SKED system (especially editing, compilation, and loading of programs), and take advantage of a file-oriented system structure for data storage and analysis.