Exploring the world through touch requires the integration of internal (e.g., anatomical) and external (e.g., spatial) reference frames — you only know what you touch when you know where your hands are in space. The deficit observed in tactile temporal-order judgements when the hands are crossed over the midline provides one tool to explore this integration. We used foot pedals and required participants to focus on either the hand that was stimulated first (an anatomical bias condition) or the location of the hand that was stimulated first (a spatiotopic bias condition). Spatiotopic-based responses produce a larger crossed-hands deficit, presumably by focusing observers on the external reference frame. In contrast, anatomical-based responses focus the observer on the internal reference frame and produce a smaller deficit. This manipulation thus provides evidence that observers can change the relative weight given to each reference frame. We quantify this effect using a probabilistic model that produces a population estimate of the relative weight given to each reference frame. We show that a spatiotopic bias can result in either a larger external weight (Experiment 1) or a smaller internal weight (Experiment 2) and provide an explanation of when each one would occur.

通过触摸探索世界需要整合内部（例如，解剖学）和外部（例如，空间）参考系——只有当您知道您的手在空间中的位置时，您才知道您触摸到了什么。当手越过中线时，在触觉时间顺序判断中观察到的缺陷提供了一种探索这种整合的工具。我们使用脚踏板并要求参与者将注意力集中在首先受到刺激的手（解剖学偏差条件）或首先受到刺激的手的位置（空间偏差条件）。基于 Spatiotopic 的响应会产生更大的双手交叉缺陷，这可能是通过将观察者集中在外部参考框架上。相比之下，基于解剖学的反应将观察者集中在内部参考框架上并产生较小的缺陷。因此，这种操作提供了证据，证明观察者可以改变赋予每个参考系的相对权重。我们使用概率模型量化这种影响，该模型产生对每个参考框架的相对权重的总体估计。我们表明，空间主题偏差可能导致更大的外部权重（实验 1）或更小的内部权重（实验 2），并解释了每种情况发生的时间。