Over the past three decades, functional magnetic resonance imaging (fMRI) has become crucial to study how cognitive processes are implemented in the human brain. However, the question of whether participants recruited into fMRI studies differ from participants recruited into other study contexts has received little to no attention. This is particularly pertinent when effects fail to generalize across study contexts: for example, a behavioural effect discovered in a non-imaging context not replicating in a neuroimaging environment. Here, we tested the hypothesis, motivated by preliminary findings (N = 272), that fMRI participants differ from behaviour-only participants on one fundamental individual difference variable: trait anxiety. Analysing trait anxiety scores and possible confounding variables from healthy volunteers across multiple institutions (N = 3317), we found robust support for lower trait anxiety in fMRI study participants, consistent with a sampling or self-selection bias. The bias was larger in studies that relied on phone screening (compared with full in-person psychiatric screening), recruited at least partly from convenience samples (compared with community samples), and in pharmacology studies. Our findings highlight the need for surveying trait anxiety at recruitment and for appropriate screening procedures or sampling strategies to mitigate this bias.

中文翻译：

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神经影像样本的代表性如何？功能磁共振成像和仅行为研究参与者之间特质焦虑差异的大规模证据

在过去的三十年里，功能磁共振成像 (fMRI) 已成为研究认知过程如何在人脑中实施的关键。然而，招募到 fMRI 研究的参与者是否与招募到其他研究环境的参与者不同的问题几乎没有受到关注。当效应无法在研究环境中推广时，这一点尤其相关：例如，在非成像环境中发现的行为效应不会在神经成像环境中复制。在这里，我们检验了这一假设，受初步调查结果 (N = 272) 的启发，fMRI 参与者与仅行为参与者在一个基本的个体差异变量上有所不同：特质焦虑。分析来自多个机构（N = 3317）的健康志愿者的特质焦虑评分和可能的混杂变量，我们发现功能磁共振成像研究参与者对较低特质焦虑的有力支持，与抽样或自我选择偏差一致。在依赖电话筛查（与全面的面对面精神病学筛查相比）、至少部分从便利样本中招募（与社区样本相比）以及药理学研究的研究中，偏差更大。我们的研究结果强调了在招聘时调查特质焦虑的必要性，并需要适当的筛选程序或抽样策略来减轻这种偏见。在依赖电话筛查（与全面的面对面精神病学筛查相比）、至少部分从便利样本中招募（与社区样本相比）以及药理学研究的研究中，偏差更大。我们的研究结果强调了在招聘时调查特质焦虑的必要性，并需要适当的筛选程序或抽样策略来减轻这种偏见。在依赖电话筛查（与全面的面对面精神病学筛查相比）、至少部分从便利样本中招募（与社区样本相比）以及药理学研究的研究中，偏差更大。我们的研究结果强调了在招聘时调查特质焦虑的必要性，并需要适当的筛选程序或抽样策略来减轻这种偏见。