Learning a new language is an important goal that many individuals find difficult to achieve, particularly during adulthood. Several factors have related this variability to different extrinsic (learning condition, difficulty of the materials) and intrinsic (cognitive abilities) factors, but the interaction between them is barely known. In two experiments, participants learned English grammar rules in intentional (Experiment 1) or explicit (Experiment 2), and incidental learning-contexts. Overall, results of this study indicated that intentional-explicit conditions benefitted rule-learning, as compared to incidental conditions. This benefit was mainly present when participants were learning an easy-rule; explicit and incidental learning did not differ in the case of participants learning a difficult rule (Experiment 2). Moreover, individual differences in executive functioning predicted successful learning in interaction with difficulty. When learning an easy-rule, proactive control facilitated intentional learning. In contrast, when participants were learning a complex-rule, incidental learning was enhanced by lower involvement of proactive control.

学习一门新语言是许多人发现难以实现的重要目标，尤其是在成年时期。有几个因素将这种变异性与不同的外在因素（学习条件、材料难度）和内在因素（认知能力）联系起来，但它们之间的相互作用却鲜为人知。在两个实验中，参与者在有意（实验 1）或显性（实验 2）以及偶然学习情境中学习了英语语法规则。总体而言，本研究的结果表明，与偶然条件相比，有意明确的条件有利于规则学习。这种好处主要出现在参与者学习简单规则时。在参与者学习困难规则的情况下，显性学习和附带学习没有差异（实验 2）。而且，执行功能的个体差异预示着在与困难的互动中成功学习。当学习简单的规则时，主动控制有助于有意识的学习。相比之下，当参与者学习复杂规则时，主动控制参与度的降低会增强附带学习。