Wilde's dot-row phenomenon as a special case of aniseikonia

Summary In this investigation on Wilde's dot-row phenomenon vertical lines were used instead of dots. If was found that within the conditions of these experiments the apparent rotation of the patterns increased with increasing difference between the width of the monocular patterns (magnification between 5% and 10%), and decreased with increasing distance between the lines of the patterns. This distance varied from 4 arcmin to 10 arcmin. The apparent rotation of the patterns could be expressed by the regression equation R=a–b₁+b₂M, in which is the distance between the lines of the patterns and M is the percentage of magnification of one of the patterns in relation to the other one. From this regression equation the apparent rotation in aniseikonic random-dot patterns could be predicted. It was concluded that Wilde's phenomenon can be considered as an aniseikonic depth effect inhibited by the equal distance between the lines of the pattern.     

Space is to time as vision is to audition: seductive but misleading

Space and time serve two perceptual functions. First, space/time forms a framework for visual and auditory events. Second, spatial and temporal change defines the properties of events and objects. It is at this second level that correspondences (i.e., mappings) between visual and auditory qualities can be hypothesized. Due to the active nature of perceiving, all such mappings illustrate the possible relations between looking and listening.     

Similarity and categorization: from vision to touch

Even though human perceptual development relies on combining multiple modalities, most categorization studies so far have focused on the visual modality. To better understand the mechanisms underlying multisensory categorization, we analyzed visual and haptic perceptual spaces and compared them with human categorization behavior. As stimuli we used a three-dimensional object space of complex, parametrically-defined objects. First, we gathered similarity ratings for all objects and analyzed the perceptual spaces of both modalities using multidimensional scaling analysis. Next, we performed three different categorization tasks which are representative of every-day learning scenarios: in a fully unconstrained task, objects were freely categorized, in a semi-constrained task, exactly three groups had to be created, whereas in a constrained task, participants received three prototype objects and had to assign all other objects accordingly. We found that the haptic modality was on par with the visual modality both in recovering the topology of the physical space and in solving the categorization tasks. We also found that within-category similarity was consistently higher than across-category similarity for all categorization tasks and thus show how perceptual spaces based on similarity can explain visual and haptic object categorization. Our results suggest that both modalities employ similar processes in forming categories of complex objects.     

Perceptual-cognitive control as a special case in equivalent multisensory-sensorimotor interactions

In his primary thesis on the purely perceptual-cognitive nature of movement control, F. Mechsner (2004) entirely neglects, or in fact negates, the influences of action on perception. In this commentary, the author follows the logical steps of Mechsner, illustrates what he conceives to be an error in Mechsner's reasoning, and synthesizes those arguments in favor of a hypothesis of a system of equivalent elements (senses and effectors) in interaction.     

Tau and Kappa effects in physical space: the case of audition

The organization of spatio-temporal information in an auditory memory task was studied in two experiments. Stimuli consisted of four different configurations of eight sequentially presented beeps. In two configurations, the stimuli were space-time congruent, with (constant or variable) inter-stimulus distances corresponding to (constant or variable) inter-stimulus time intervals. In the other two configurations, the stimuli were space-time incongruent, with (constant or variable) inter-stimulus distances not corresponding to (variable or constant) inter-stimulus time intervals. After a learning phase consisting of 20 presentations of the target configuration, participants reproduced the spatial (Experiment 1) or temporal (Experiment 2) characteristics of the target 60 times in succession without re-examining the target configuration. Accuracy (with respect to the target) and variability (between responses) were found to evolve independently. In the incongruent space-time conditions, effects of variable inter-stimulus time intervals or distances on the reproduction of, respectively, constant distances (Tau effect) or constant time intervals (Kappa effect) were observed, while the reverse was not the case. Thus, dimensional interference occurred when the dimension to be ignored was variable. The results are discussed in the light of the distinction between properties of the stabilized mental image and the process of stabilization.     

Short-term memory as a function of input modality

The two experiments reported are concerned with short-term memory for digit lists simultaneously presented both auditorily and visually. Results showed (1) that interpolated written and verbal recall differentially affect retention depending on whether the to-be-recalled list was presented auditorily or visually. (2) That input modality appears to be far more important for recall than was directing subjects' attention to a list during input, when that list might or might not have been subsequently required for recall. The results suggest that short-term storage is modality specific. In this case, Broadbent's P and S mechanisms do not adequately describe what happens during simultaneous visual and auditory presentation. Nor would Sperling's suggestion of a final auditory store appear to be supported.     

Visual recalibration of auditory speech identification: a McGurk aftereffect

The kinds of aftereffects, indicative of cross-modal recalibration, that are observed after exposure to spatially incongruent inputs from different sensory modalities have not been demonstrated so far for identity incongruence. We show that exposure to incongruent audiovisual speech (producing the well-known McGurk effect) can recalibrate auditory speech identification. In Experiment 1, exposure to an ambiguous sound intermediate between /aba/ and /ada/ dubbed onto a video of a face articulating either /aba/ or /ada/ increased the proportion of /aba/ or /ada/ responses, respectively, during subsequent sound identification trials. Experiment 2 demonstrated the same recalibration effect or the opposite one, fewer /aba/ or /ada/ responses, revealing selective speech adaptation, depending on whether the ambiguous sound or a congruent nonambiguous one was used during exposure. In separate forced-choice identification trials, bimodal stimulus pairs producing these contrasting effects were identically categorized, which makes a role of postperceptual factors in the generation of the effects unlikely.     

The corpus callosum: Some anatomical and functional considerations with special reference to language

Recent studies on the anatomy and development of the corpus callosum (CC) are reviewed, and discussed in relation to present theories of the function of the CC. The contributions of various pathological conditions of the CC, as well as that of the split-brain studies, to the understanding of the functions of the CC are considered. The recent theory that the language dominant hemisphere exerts inhibitory influences over the nondominant hemisphere via the CC did not receive much support, and an alternative theory implicating the CC in the establishment of lateralization of language is presented. Direct evidence for this view is as yet not available, but it receives some support from cases of agenesis of the CC.     

Symbols presentation modality as a determinant of gambling behavior

In this study, the authors investigated the effects that modality of symbol presentation on video lottery terminals (sequential vs. simultaneous) has on gambling behavior. They predicted that sequential presentation would incite players to prolong their gambling session. Results confirmed this prediction and showed that modality of presentation is a determinant of gambling persistency. The authors discuss the relationship between modality of presentation, hopes of an imminent win, losses, and practical and theoretical issues about other cognitive and emotional elements that may influence gamblers' behaviors.     

Mislocalizations of touch to a fake hand

Observers can mislocalize a tactile target delivered to an unseen hand if a visible rubber glove is positioned next to a pair of distractor lights that flash in correlation with the tactile target (Pavani, Spence, & Driver, 2000). In the present study, we explored visual, tactile, and postural factors that influence this fake hand effect. Comparison with baseline conditions revealed that the fake hand effect was larger than a general spatial congruity effect but weaker than the effect obtained when tactile and visual stimuli were actually in the same locations (Experiment 1). Surprisingly, the effect did not depend on direct vision of the fake hand (Experiments 1 and 2), nor was it enhanced by congruent tactile information (Experiment 3). However, the fake hand effect was sensitive to the postural compatibility of the real and the fake hands (Experiment 4). These findings indicate that the available sensory information is used flexibly to incorporate the rubber glove into the body schema.     

On substantial independence: a reply to Patrick Toner

Patrick Toner has recently criticized accounts of substance provided by Kit Fine, E. J. Lowe, and the author, accounts which say (to a first approximation) that substances cannot depend on things other than their own parts. On Toner??s analysis, the inclusion of this ??parts exception?? results in a disjunctive definition of substance rather than a unified account. In this paper (speaking only for myself, but in a way that would, I believe, support the other authors that Toner discusses), I first make clear what Toner??s criticism is, and then I respond to it. Including the ??parts exception?? is not the adding of a second condition but instead the creation of a new single condition. Since it is not the adding of a condition, the result is not disjunctive. Therefore, the objection fails.     

Adaptation to displaced vision: Reafference is a special case of the cue-discrepancy hypothesis

Subjects were exposed to a prismatically displaced view of their actively-moved right hand which was optically “stopped”; they achieved as much adaptation in this condition as in one in which they were allowed full “reafferent” stimulation. This provides further evidence against Held's “reafference“ hypothesis.     

Aging and perceived event structure as a function of modality

The majority of research on situation model processing in older adults has focused on narrative texts. Much of this research has shown that many important aspects of constructing a situation model for a text are preserved and may even improve with age. However, narratives need not be text-based, and little is known as to whether these findings generalize to visually-based narratives. The present study assessed the impact of story modality on event segmentation, which is a basic component of event comprehension. Older and younger adults viewed picture stories or read text versions of them and segmented them into events. There was comparable alignment between the segmentation judgments and a theoretically guided analysis of shifts in situational features across modalities for both populations. These results suggest that situation models provide older adults with a stable basis for event comprehension across different modalities of expereinces.