Kunar Melina A, Rich Anina N, Wolfe Jeremy M
The University of Warwick.
Vis cogn. 2010 Jun 1;18(6):881-897. doi: 10.1080/13506280903361988.
Recent research has shown that, in visual search, participants can miss 30-40% of targets when they only appear rarely (i.e. on 1-2% of trials). Low target prevalence alters the behavior of the searcher. It can lead participants to quit their search prematurely (Wolfe et al., 2005), to shift their decision criteria (Wolfe et al., 2007) and/or to make motor or response errors (Fleck & Mitroff, 2007). In this paper we examine whether the LP Effect can be ameliorated if we split the search set in two, spreading the task out over space and/or time. Observers searched for the letter "T" among "L"s. In Experiment 1, the left or right half of the display was presented to the participants before the second half. In Experiment 2, items were spatially intermixed but half of the items were presented first, followed by the second half. Experiment 3 followed the methods of Experiment 2 but allowed observers to correct perceived errors. All three experiments produced robust low prevalence (LP) effects with higher errors at 2% prevalence than at 50% prevalence. Dividing up the display had no beneficial effect on errors. The opportunity to correct errors reduced but did not eliminate the LP effect. Low prevalence continues to elevate errors even when observers are forced to slow down and permitted to correct errors.
最近的研究表明，在视觉搜索中，当目标出现频率很低时（即仅在1%-2%的试验中出现），参与者可能会错过30%-40%的目标。低目标出现率会改变搜索者的行为。它可能导致参与者过早停止搜索（沃尔夫等人，2005年），改变他们的决策标准（沃尔夫等人，2007年）和/或出现动作或反应错误（弗莱克和米特罗夫，2007年）。在本文中，我们研究了如果将搜索集一分为二，在空间和/或时间上分散任务，是否可以改善低出现率效应（LP效应）。观察者在“L”中搜索字母“T”。在实验1中，显示屏的左半部分或右半部分先呈现给参与者，然后再呈现后半部分。在实验2中，项目在空间上混合，但一半的项目先呈现，然后是另一半。实验3遵循实验2的方法，但允许观察者纠正感知到的错误。所有三个实验都产生了显著的低出现率（LP）效应，2%出现率时的错误率高于50%出现率时的错误率。分割显示屏对错误没有有益影响。纠正错误的机会减少了，但并没有消除LP效应。即使观察者被迫放慢速度并被允许纠正错误，低出现率仍然会增加错误率。
