1,721,012 research outputs found
Colours + Numbers differs from colours of numbers: cognitive and visual illusions in grapheme-colour synaesthesia
No full textThis study investigates the bi-directionality of synaestesic experience by means of a flanked bisection paradigm in TT, a number-colour synaesthete. Previous studies have shown that bisection is shifted towards the larger digit flanker (e.g., Ranzini & Girelli, 2012). TT and controls performed line bisections with lines flanked by black digits (experiment 1), by TT’s photism colours (experiment 2), and by congruently (experiment 3), or incongruently coloured digits (experiment 4). While the results of the control group mainly replicated previous findings, only the colour-digit congruence elicited in TT the larger-digit bias. TT’s absence of effects in the other conditions was not due to reduced sensitivity to luminance effects (experiment 5), or to mathematical expertise (experiment 6). We suggest that grapheme-colour synaesthesia might be characterised by a rigid access to semantic representation when the inducer is task-irrelevant
Exploiting illusory effects to disclose similarities in numerical and luminance processing.
Full text linkRecent studies have suggested that numerical and physical magnitudes are similarly processed by a generalized magnitude system. The present study investigates the number-luminance interaction, taking advantage of illusory effects in a cued line bisection task with numerical or nonnumerical flankers and varying levels of luminance. The results showed that both dimensions influenced bisection performance. Whereas numbers (Experiment 1) induced a systematic shift of the subjective midpoint toward the larger digit, luminance (Experiment 2) modulated the bisection performance toward the darker flanker. By combining these two illusions (Experiments 3 and 4), the two dimensions interfered with each other. This pattern of results suggests overlapping representations for physical and numerical magnitudes and highlights the value of illusory effects in cognitive research.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe
Contribution of visuospatial attention, short-term memory and executive functions to performance in number interval bisection
No full textNumber interval bisection consists of estimating the mid-number within a pair (1–9=>5). Healthy adults and right-brain damage patients can show biased performance in this task, underestimating and overestimating the mid-number, respectively. The role of visuospatial attention during this task, and its interplay with other cognitive abilities (e.g., working memory) is still object of debate. In this study we explored the relation between visuospatial attention and individual differences in working memory and executive functions during number interval bisection. To manipulate the deployment of visuospatial attention, healthy participants tracked a dot moving to the left or moving to the right while bisecting numerical intervals. We also collected information concerning verbal and visuospatial short-term memory span, and concerning verbal and visuospatial fluency scores. Beside replicating what is typically observed in this task (e.g., underestimation bias), a correlation was observed between verbal short-term memory and bisection bias, and an interesting relation between performance in the number interval bisection, verbal short-term memory, and visuospatial attention. Specifically, performance of those participants with low verbal span was affected by the direction of the moving dot, underestimating at a larger extent when the dot moved leftward than rightward. Finally, it was also observed that participants’ verbal fluency ability contributed in the generation of biases in the numerical task. The finding of the involvement of abilities belonging to the verbal domain contributes to unveil the multi-componential nature of number interval bisection. Considering the debate on the nature of number interval bisection and its use in the clinical assessment of deficits following brain damage, this finding may be interesting also from a clinical perspective
What information is critical to elicit interference in number-form synaesthesia?
No full textNumerous behavioural paradigms have demonstrated a close connection between numbers and space, suggesting that numbers may be represented on an internal mental number line. For example, in the Spatial Numerical Association of Response Codes (SNARC) effect, reaction times are faster for left-sided responses to smaller numbers and for right-sided responses to larger numbers. One valuable tool for exploring such numerical-spatial interactions is the study of number-form synaesthesia, in which participants report vivid, automatic associations of numerical and other ordinal sequences with precise, idiosyncratic, spatial layouts. Recent studies have demonstrated the influence of synaesthetic spatial experiences on behavioural number tasks. The aim of the present study is to further explore these internal spatial representations by presenting a case-study of an unusual synaesthete, DG, who reports highly detailed representations not only of numerical sequences (including representations of negative and Roman numbers), but also different representations for other ordinal sequences, such as time sequences (months, days and hours), the alphabet, financial sequences and different units of measure (e.g., kilograms, kilometres and degrees). Here, we describe DG's synaesthetic experiences and a series of behavioural experiments on numerical tasks concerning the automaticity of this phenomenon. DG's performance on number comparison and cued-detection tasks was modulated by his synaesthetic mental representation for the numerical sequence, such that his reaction times were slower when the spatial layout was incompatible with the orientation of his mental number line. We found that the spatial presentation of stimuli, rather than the implicit or explicit access to numerosity required by tasks, was essential to eliciting DG's number-forms. These results are consistent with previous studies and suggest that numerical-spatial interactions may be most strongly present in synaesthetes when both numerical and spatial information are explicitly task-relevant, consistent with a growing body of literature regarding the SNARC and other related effects
Neural mechanisms of attentional shifts due to irrelevant spatial and numerical cues
No full textStudies of endogenous (cue-directed) attention have traditionally assumed that such shifts must be volitional. However, recent behavioural experiments have shown that participants make automatic endogenous shifts of attention when presented with symbolic cues that are systematically associated with particular spatial directions, such as arrows and numerals, even when such cues were not behaviourally relevant. Here we used event-related potentials (ERPs) to test whether these automatic shifts of attention use the same mechanisms as volitional shifts of attention. We presented participants with non-predictive (50% valid) task-irrelevant arrow and numeral cues while measuring cue- and target-locked ERPs. Although the cues were task-irrelevant, they elicited attention-related ERP components previously found in studies that used informative and/or task-relevant cues. These findings further substantiate the dissociation between endogenous and volitional attentional control, and suggest that the same fronto-parietal networks involved in volitional shifts of attention are also involved in reflexive endogenous shifts of attention
Effects of attentional shifts along the vertical axis on number processing: An eye-tracking study with optokinetic stimulation
Full text linkPrevious studies suggest that associations between numbers and space are mediated by shifts of visuospatial attention along the horizontal axis. In this study, we investigated the effect of vertical shifts of overt attention, induced by optokinetic stimulation (OKS) and monitored through eye-tracking, in two tasks requiring explicit (number comparison) or implicit (parity judgment) processing of number magnitude. Participants were exposed to black-and-white stripes (OKS) that moved vertically (upward or downward) or remained static (control condition). During the OKS, participants were asked to verbally classify auditory one-digit numbers as larger/smaller than 5 (comparison task; Exp. 1) or as odd/even (parity task; Exp. 2). OKS modulated response times in both experiments. In Exp.1, upward attentional displacement decreased the Magnitude effect (slower responses for large numbers) and increased the Distance effect (slower responses for numbers close to the reference). In Exp.2, we observed a complex interaction between parity, magnitude, and OKS, indicating that downward attentional displacement slowed down responses for large odd numbers. Moreover, eye tracking analyses revealed an influence of number processing on eye movements both in Exp. 1, with eye gaze shifting downwards during the processing of small numbers as compared to large ones; and in Exp. 2, with leftward shifts after large even numbers (6,8) and rightward shifts after large odd numbers (7,9). These results provide evidence of bidirectional links between number and space and extend them to the vertical dimension. Moreover, they document the influence of visuo-spatial attention on processing of numerical magnitude, numerical distance, and parity. Together, our findings are in line with grounded and embodied accounts of numerical cognition
Nomina sunt consequentia rerum - Sound-shape correspondences with every-day objects figures
No full textPrior research on sound-symbolism has demonstrated the existence of sound-shape correspondences using ad hoc figures in double forced-choice paradigms. This led sound-symbolic skeptics to affirm that the reported effects were due to the properties of the figures shown or to the structure of the task used. In the present study, we hypothesized that the sound-shape correspondence effect would be observed when participants were required to choose which of two invented words would better suit an image representing a common object/entity. In addition, we hypothesized that the effect would be modulated by the object/entity category, and that natural objects would be represented with smoother shapes compared to artifacts. Results confirmed the "classic" takete-maluma effect both when participants chose a name for figures of natural objects (e.g., leaf) and artifacts (e.g., fork), and when they chose a name for figures of natural (e.g., animals) and artificial agents (e.g., robots). Moreover, when participants had to name agents, a modulation of the category (artificial vs. natural) emerged: sound-shape correspondence was not observed with robots, which were associated more often with jagged responses despite their actual shape. Results are discussed in the framework of embodied cognition theories
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