Key Laboratory of Adolescent Cyberpsychology and Behavior (CCNU), Ministry of Education, Wuhan, China.
School of Psychology, Central China Normal University, No. 382, XiongChu Road, Hongshan District, Wuhan, 430079, Hubei Province, China.
BMC Psychol. 2022 Nov 4;10(1):251. doi: 10.1186/s40359-022-00953-y.
Emotional stimuli used as targets of working memory (WM) tasks can moderate age-related differences in WM performance, showing that aging is associated with reductions in negativity bias. This phenomenon is referred to as the positivity effect. However, there is little research on whether emotional distractors have a similar moderating effect. Moreover, the underlying neural mechanism of this effect has not been studied. In this study, we examined the behavioral and neurophysiological basis for age differences in resistance to emotional distractors within WM.
Older adults (n = 30, ages 60-74) and young adults (n = 35, ages 19-26) performed a 2-back task in which a digit was superimposed on a face with a happy, angry, or neutral expression as a distractor. Event-related potential (ERP) was simultaneously recorded to assess P2, N2, and later positive potential (LPP) amplitudes.
Older adults were less accurate and slower than young adults on the WM task. Moreover, the results demonstrated a significant interaction between age and emotional valence on response accuracy, young adults' performance was worse when the distractor was neutral or positive than when it was negative, but there was no effect of the emotional valence of distractors on older adults' WM performance. ERP analyses revealed greater P2 amplitude in older adults than young adults, regardless of the emotional valence of distractors. However, older adults and young adults did not differ on N2 or LPP amplitude, and negative distractors elicited greater N2 than positive distractors in both age groups.
The behavioral findings provided evidence of age-related reductions in negativity bias. Thus, the behavioral measures indicated a positivity effect in WM. However, the ERP results did not show this same interaction. These discrepant results raise questions about whether and to what extent older and young adults differ in controlling the effect of emotional distractors in WM.
作为工作记忆（WM）任务的目标的情绪刺激可以调节 WM 表现的年龄相关差异，表明衰老与负性偏差的减少有关。这种现象被称为正性效应。然而，关于情绪干扰物是否具有类似的调节作用的研究甚少。此外，这种效应的潜在神经机制尚未研究。在这项研究中，我们研究了 WM 中情绪干扰物对抵抗能力的年龄差异的行为和神经生理基础。
老年组（n=30，年龄 60-74 岁）和年轻组（n=35，年龄 19-26 岁）进行了 2 -back 任务，其中数字与具有快乐、愤怒或中性表情的面孔叠加作为干扰物。同时记录事件相关电位（ERP）以评估 P2、N2 和后期正性电位（LPP）的振幅。
老年组在 WM 任务中的准确性和速度均低于年轻组。此外，结果表明年龄与情绪效价之间的交互作用在反应准确性上存在显著差异，当干扰物为中性或阳性时，年轻组的表现比负性时差，但干扰物的情绪效价对老年组的 WM 表现没有影响。ERP 分析表明，无论干扰物的情绪效价如何，老年组的 P2 振幅均大于年轻组。然而，老年组和年轻组在 N2 或 LPP 振幅上没有差异，并且在两个年龄组中，负性干扰物诱发的 N2 大于正性干扰物。
行为研究结果提供了年龄相关的负性偏差减少的证据。因此，行为测量在 WM 中表现出正性效应。然而，ERP 结果并未显示出相同的交互作用。这些不一致的结果提出了关于老年和年轻个体在 WM 中控制情绪干扰物影响方面是否存在差异以及差异程度的问题。
