Bourgeois Alexia, Neveu Rémi, Vuilleumier Patrik
Neuroscience Department, Laboratory for Behavioral Neurology and Imaging of Cognition, University of Geneva, Geneva, Switzerland.
PLoS One. 2016 Aug 2;11(8):e0160469. doi: 10.1371/journal.pone.0160469. eCollection 2016.
In order to behave adaptively, attention can be directed in space either voluntarily (i.e., endogenously) according to strategic goals, or involuntarily (i.e., exogenously) through reflexive capture by salient or novel events. The emotional or motivational value of stimuli can also strongly influence attentional orienting. However, little is known about how reward-related effects compete or interact with endogenous and exogenous attention mechanisms, particularly outside of awareness. Here we developed a visual search paradigm to study subliminal value-based attentional orienting. We systematically manipulated goal-directed or stimulus-driven attentional orienting and examined whether an irrelevant, but previously rewarded stimulus could compete with both types of spatial attention during search. Critically, reward was learned without conscious awareness in a preceding phase where one among several visual symbols was consistently paired with a subliminal monetary reinforcement cue. Our results demonstrated that symbols previously associated with a monetary reward received higher attentional priority in the subsequent visual search task, even though these stimuli and reward were no longer task-relevant, and despite reward being unconsciously acquired. Thus, motivational processes operating independent of conscious awareness may provide powerful influences on mechanisms of attentional selection, which could mitigate both stimulus-driven and goal-directed shifts of attention.
为了适应性地行动，注意力可以根据战略目标在空间上被自愿地（即内源性地）引导，或者通过显著或新颖事件的反射性捕获被非自愿地（即外源性地）引导。刺激的情感或动机价值也会强烈影响注意力的定向。然而，关于奖励相关效应如何与内源性和外源性注意力机制竞争或相互作用，尤其是在意识之外的情况，我们知之甚少。在这里，我们开发了一种视觉搜索范式来研究基于阈下价值的注意力定向。我们系统地操纵目标导向或刺激驱动的注意力定向，并检查一个无关但先前得到奖励的刺激在搜索过程中是否能与两种类型的空间注意力竞争。关键的是，在前面一个阶段，在没有意识觉知的情况下学习奖励，在这个阶段，几个视觉符号中的一个与阈下金钱强化线索持续配对。我们的结果表明，先前与金钱奖励相关联的符号在随后的视觉搜索任务中获得了更高的注意力优先级，即使这些刺激和奖励不再与任务相关，并且尽管奖励是在无意识的情况下获得的。因此，独立于意识觉知运作的动机过程可能对注意力选择机制产生强大影响，这可能减轻注意力的刺激驱动和目标导向转移。
