Perceptual long-term memory in visual search

在视觉搜索中，人类的表现依赖于几种不同的线索，这些线索可以帮助人们集中注意力。其中一个线索是上下文信息，即习得的目标-分心物安排（例如，Chun, 2000; TICS 4: 170-178）。在标准的上下文线索搜索任务中，观察者搜索目标字母T（干扰字母L）并报告其方向（向左与向右）。在重复条件下，目标-分心物的安排在不同的试验中是重复的；在非重复条件下，只有目标而不是干扰物的位置是重复的（这等于两个条件之间的目标位置重复效应）。通常，重复条件包括一组12种不同的显示，具有特定的目标-干扰配置，在整个实验过程中反复出现。标准的发现是，重复显示的反应时间（RTs）比非重复显示的反应时间要快，这一效应在大约100到150次实验试验后出现（即，在每个重复显示重复4-6次之后）。通常，这些发现被认为意味着学习目标-干扰物安排的长期记忆有助于视觉搜索。有趣的是，当观察者被问及在搜索实验结束时通过识别测试进行的重复显示时，他们只在偶然水平上表现。这导致了上下文线索由内隐记忆系统支持的提议（cf. Chun & Jiang, 2003; JEP:LMC 29: 224-234）。然而，最近对线索效应的研究，包括我们自己的研究，发现这种效应是由于（4±2）次重复显示的数量非常有限（Geyer, Shi, & m<e:1>勒，2010;JEP:HPP 36: 515-532）。这意味着，似乎只有极少数的重复显示有助于提示效应，而不是学习所有或大多数重复显示。此外，当同时评估上下文线索和识别性能时，发现观察者可以区分重复和非重复的显示，至少是一些重复的显示（Smyth & Shanks, 2008; Schlagbauer et al. 2012）。这意味着提示效应最终是由显式记忆系统支持的。鉴于此，本研究的主要目的是：(1)研究调节重复搜索显示学习的条件（因素）（实验系列1,2,4,5）；(2)揭示线索效应与视觉意识之间的关系（实验系列3,6）。所有实验的一个重要特征是在每个重复显示的水平上分析因变量（反应时间，识别性能，动眼力变量，电生理测量）。

In visual search, human performance relies on several different cues that can aid attention. One of these cues is contextual information, that is, the learned target-distractor arrangement (e.g., Chun, 2000; TICS 4: 170-178). In a standard contextual cueing search task, observers search for the target letter T (distractor letters L) and report its orientation (left- vs. right-oriented). In the repeated condition, the target-distractor arrangement is repeated across trials; in the non-repeated condition, only target, but not distractor, locations are repeated (this equates target location repetition effects between the two conditions). Typically, the repeated condition consists of a set of 12 different displays with a certain target-distractor configuration that is presented repeatedly throughout the course of the experiment. The standard finding is that reaction times (RTs) are faster for repeated than non-repeated displays, an effect which emerges after about 100 to 150 experimental trials (i.e., after 4-6 repetitions of each of the repeated displays). Typically, these findings are taken to mean that long-term memory for learnt target-distractor arrangements facilitates visual search. Interestingly, when observers are asked about repeated displays by means of a recognition test performed at the end of the search experiment, they only perform at chance level. This has led to the proposal that contextual cueing is supported by an implicit memory system (cf. Chun & Jiang, 2003; JEP:LMC 29: 224-234). However, more recent investigations of the cueing effect, including our own, found that the effect is due to only a very limited number of (4±2) repeated displays (Geyer, Shi, & Müller, 2010; JEP:HPP 36: 515-532). This means that rather than learning about all or most repeated displays, it seems that only a very small number of repeated displays contributes to the cueing effect. Further, when assessing contextual cueing and recognition performance concurrently, it was found that observers could tell apart repeated from non-repeated displays, at least some of the repeated displays (Smyth & Shanks, 2008; Schlagbauer et al. 2012). This means that the cueing effect is eventually supported by an explicit memory system. Given this, the main aims of the proposed research are (1) to investigate the conditions (factors) that modulate the learning of repeated search displays (experimental series 1, 2, 4, 5); and (2), to shed new light on the relation between the cueing effect and visual awareness (experimental series 3, 6). One important feature of all experiments is the analysis of the dependent variables (reaction times, recognition performance, oculomotor variables, electrophysiological measures) at the level of each of the repeated displays.