ABSTRACT

Spatial influences may be introduced to an experimental task by manipulations performed on the stimulus or the response or by virtue of the type of stimuli under study. Identification of spatial influences is especially pertinent in investigations of laterality, as isolation of processing to one hemisphere may inadvertently introduce spatial confounds. Because, however, space is not a relevant task feature, it may not always be obvious that it should be taken into consideration. Failure to anticipate these spatial influences can affect the conclusions drawn from results. The current work examines potential spatial influences in an experimental paradigm previously used to investigate perceptual asymmetries for duration estimation in which both stimulus presentation and response selection were lateralized. Potential spatial influences (including the spatial-temporal association of response codes – STEARC, spatial attention, and the Simon effect) are identified and systematically tested over 5 experiments. Results suggest that previously observed perceptual asymmetries in this experimental paradigm may be the result of a spatial confound, specifically, that of the Simon effect. Using vertical response options with the lateral stimulus presentation, however, mitigated the spatial influence. Altogether, the current work demonstrates the importance of carefully considering potential spatial confounds prior to commencement of laterality studies.

摘要

空间影响可以通过对刺激或响应进行的操作或根据所研究的刺激类型来引入实验任务。识别空间影响在研究偏侧性时尤其重要，因为将处理隔离到一个半球可能会无意中引入空间混淆。然而，因为空间不是相关的任务特征，所以可能并不总是很明显应该考虑它。未能预测这些空间影响可能会影响从结果中得出的结论。目前的工作检查了以前用于研究持续时间估计的感知不对称性的实验范式中的潜在空间影响，其中刺激呈现和响应选择都被横向化。潜在的空间影响（包括响应代码的时空关联 - STEARC、空间注意力和西蒙效应）在 5 次实验中被识别和系统测试。结果表明，先前在该实验范式中观察到的感知不对称可能是空间混淆的结果，特别是西蒙效应的结果。然而，使用带有横向刺激呈现的垂直响应选项，减轻了空间影响。总而言之，目前的工作证明了在开始偏侧性研究之前仔细考虑潜在空间混淆的重要性。结果表明，先前在该实验范式中观察到的感知不对称可能是空间混淆的结果，特别是西蒙效应的结果。然而，使用带有横向刺激呈现的垂直响应选项，减轻了空间影响。总而言之，目前的工作证明了在开始偏侧性研究之前仔细考虑潜在空间混淆的重要性。结果表明，先前在该实验范式中观察到的感知不对称可能是空间混淆的结果，特别是西蒙效应的结果。然而，使用带有横向刺激呈现的垂直响应选项，减轻了空间影响。总而言之，目前的工作证明了在开始偏侧性研究之前仔细考虑潜在空间混淆的重要性。