Rugani Rosa, Betti Sonia, Sartori Luisa
Department of General Psychology, University of Padua, Padua, Italy.
Padova Neuroscience Center, University of Padua, Padua, Italy.
Front Psychol. 2018 May 1;9:637. doi: 10.3389/fpsyg.2018.00637. eCollection 2018.
Humans represent symbolic numbers as oriented from left to right: the mental number line (MNL). Up to now, scientific studies have mainly investigated the MNL by means of response times. However, the existing knowledge on the MNL can be advantaged by studies on motor patterns while responding to a number. Cognitive representations, in fact, cannot be fully understood without considering their impact on actions. Here we investigated whether a motor response can be influenced by number processing. Participants seated in front of a little soccer goal. On each trial they were visually presented with a numerical (2, 5, 8) or a non-numerical ($) stimulus. They were instructed to kick a small ball with their right index toward a frontal soccer goal as soon as a stimulus appeared on a screen. However, they had to refrain from kicking when number five was presented (no-go signal). Our main finding is that performing a kicking action after observation of the larger digit proved to be more efficient: the trajectory path was shorter and lower on the surface, velocity peak was anticipated. The smaller number, instead, specifically altered the temporal and spatial aspects of trajectories, leading to more prolonged left deviations. This is the first experimental demonstration that the reaching component of a movement is influenced by number magnitude. Since this paradigm does not require any verbal skill and non-symbolic stimuli (array of dots) can be used, it could be fruitfully adopted to evaluate number abilities in children and even preschoolers. Notably, this is a self-motivating and engaging task, which might help children to get involved and to reduce potential arousal connected to institutional paper-and-pencil examinations.
心理数字线（MNL）。到目前为止，科学研究主要通过反应时间来研究MNL。然而，通过对数字反应时的运动模式进行研究，可以进一步丰富我们对MNL的现有认识。事实上，如果不考虑认知表征对行为的影响，就无法完全理解它们。在这里，我们研究了数字处理是否会影响运动反应。参与者坐在一个小型足球门前。在每次试验中，他们会在视觉上看到一个数字（2、5、8）或非数字（$）刺激。他们被指示在屏幕上出现刺激时，立即用右手食指将一个小球踢向正面的足球门。然而，当出现数字5时（禁止信号），他们必须忍住不踢。我们的主要发现是，在观察到较大数字后执行踢腿动作被证明更有效：轨迹路径更短且在表面更低，速度峰值提前出现。相反，较小的数字特别改变了轨迹的时间和空间方面，导致更长时间的向左偏差。这是第一个实验证明，运动的伸手动作成分会受到数字大小的影响。由于这种范式不需要任何语言技能，并且可以使用非符号刺激（点阵），因此它可以有效地用于评估儿童甚至学龄前儿童的数字能力。值得注意的是，这是一项自我激励且引人入胜的任务，这可能有助于儿童参与其中，并减少与传统纸笔考试相关的潜在焦虑。
