Kristjánsson Arni, Sigurjónsdóttir Olafía, Driver Jon
University of Iceland, Reykjavik, Iceland.
Atten Percept Psychophys. 2010 Jul;72(5):1229-36. doi: 10.3758/APP.72.5.1229.
Rewards have long been known to modulate overt behavior. But their possible impact on attentional and perceptual processes is less well documented. Here, we study whether the (changeable) reward level associated with two different pop-out targets might affect visual search and trial-to-trial target repetition effects (see Maljkovic & Nakayama, 1994). Observers searched for a target diamond shape with a singleton color among distractor diamond shapes of another color (e.g., green among red or vice versa) and then judged whether the target had a notch at its top or bottom. Correct judgments led to reward, with symbolic feedback indicating this immediately; actual rewards accumulated for receipt at study end. One particular target color led to a higher (10:1) reward for 75% of its correct judgments, whereas the other singleton target color (counterbalanced over participants) yielded the higher reward on only 25% of the trials. We measured search performance in terms of inverse efficiency (response time/proportion correct). The reward schedules not only led to better performance overall for the more rewarding target color, but also increased trial-to-trial priming for successively repeated targets in that color. The actual level of reward received on the preceding trial affected this, as did (orthogonally) the likely level. When reward schedules were reversed within blocks, without explicit instruction, corresponding reversal of the impact on search performance emerged within around 6 trials, asymptoting at around 15 trials, apparently without the observers' explicit knowledge of the contingency. These results establish that pop-out search and target repetition effects can be influenced by target reward levels, with search performance and repetition effects dynamically tracking changes in reward contingency.
长期以来，人们都知道奖励会调节公开行为。但其对注意力和感知过程可能产生的影响，相关记录则较少。在此，我们研究与两个不同的突出目标相关的（可变）奖励水平是否会影响视觉搜索以及逐次试验的目标重复效应（见马尔科维奇和中山，1994）。观察者在另一种颜色的干扰菱形形状（例如红色中的绿色或反之亦然）中搜索具有单一颜色的目标菱形形状，然后判断目标在其顶部或底部是否有一个凹口。正确判断会带来奖励，符号反馈会立即表明这一点；实际奖励在研究结束时累积领取。一种特定的目标颜色在其75%的正确判断中会带来更高（10:1）的奖励，而另一种单一目标颜色（在参与者中进行了平衡）仅在25%的试验中产生更高的奖励。我们根据反向效率（反应时间/正确比例）来衡量搜索表现。奖励计划不仅总体上使更具奖励性的目标颜色表现更好，而且还增加了该颜色中连续重复目标的逐次试验启动效应。前一次试验获得的实际奖励水平对此有影响，可能的奖励水平（正交地）也有影响。当奖励计划在各块内反转时，在没有明确指示的情况下，对搜索表现的影响在大约6次试验内出现相应反转，在大约15次试验时渐近，显然观察者并未明确知晓这种偶然性。这些结果表明，突出搜索和目标重复效应会受到目标奖励水平的影响，搜索表现和重复效应会动态跟踪奖励偶然性的变化。
