Bultitude Janet H, Aimola Davies Anne M
School of Psychology, The Australian National University, Canberra, Australia.
Neuropsychologia. 2006;44(10):1849-58. doi: 10.1016/j.neuropsychologia.2006.03.001. Epub 2006 May 15.
Neurologically healthy participants systematically misbisect horizontal lines to the left of centre, a phenomenon termed 'pseudoneglect'. According to the activation-orientation hypothesis, the distribution of attention is biased in the direction opposite to the more activated hemisphere. Since visuospatial tasks involve activation of the right hemisphere, the hypothesis suggests that a leftward line-bisection bias might be explained by the uneven distribution of attention to the left and right line segments. A crucial assumption of this explanation is that the more attended half of the line will be perceived as longer than the less attended half. This study uses a tachistoscopic Landmark test and an attention cueing paradigm to explore this assumption. Three conditions were met to demonstrate the relative elongation of the more attended half of the line: (1) attention was biased to the cued end of the line, (2) subjective line midpoint was shifted towards the cued end, and (3) alternative biasing factors were ruled out. The results also demonstrate that increased hemispheric activation, resulting from presentation of stimuli in one or the other visual field, leads to subjective midpoints that are biased away from the more activated hemisphere.
神经系统健康的参与者会系统性地将水平线段的中点误判在中心左侧，这种现象被称为“假性忽视”。根据激活-方向假说，注意力的分布在与激活程度较高的半球相反的方向上存在偏差。由于视觉空间任务涉及右半球的激活，该假说认为向左的线段二等分偏差可能是由于对左右线段的注意力分布不均所致。这种解释的一个关键假设是，被更多关注的线段一半会被感知为比关注较少的一半更长。本研究使用速示地标测试和注意力提示范式来探究这一假设。满足了三个条件以证明被更多关注的线段一半的相对延长：（1）注意力偏向线段的提示端，（2）主观线段中点向提示端偏移，以及（3）排除了其他偏向因素。结果还表明，由于在一个或另一个视野中呈现刺激而导致的半球激活增加，会导致主观中点向远离激活程度较高半球的方向偏移。
