The expression big headed is often used to describe narcissists, however is it possible that this term signals a bias in how narcissists perceive themselves? We tested whether narcissistic traits predicted biases in the estimated size and weight of specific body parts, including head circumference and brain weight. In two questionnaire-based studies, participants estimated the size or weight of parts of their body. In Study 1 (n = 316), we found that the Leadership/Authority facet of narcissism significantly predicted greater estimates of head circumference in men, but lower estimates of head circumference in women. In Study 2 (n = 275), we found that when a sex-specific average head circumference was not provided, Leadership/Authority predicted greater estimates of head circumference overall. We present evidence that narcissism predicts biases in estimated head size and brain weight, but that the precise nature of these biases is dependent on the provided frame of reference for body size. These results are discussed with reference to within-sex competitive strategies, perceived intelligence and stereotypes for male and female attractiveness.

中文翻译：

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我的比你的大！自恋预测感知头部大小的偏差

“大头”这个词经常被用来描述自恋者，但是这个词是否可能表明自恋者如何看待自己的偏见？我们测试了自恋特征是否预测了特定身体部位（包括头围和大脑重量）的估计大小和重量的偏差。在两项基于问卷的研究中，参与者估计了他们身体部位的大小或重量。在研究 1 (n = 316) 中，我们发现自恋的领导/权威方面显着预测男性头围的估计值更高，但女性的头围估计值更低。在研究 2 (n = 275) 中，我们发现当没有提供特定性别的平均头围时，领导/权威预测整体头围的估计值更高。我们提供的证据表明，自恋会预测估计的头部大小和大脑重量的偏差，但这些偏差的确切性质取决于提供的体型参考框架。这些结果将参考性别内的竞争策略、感知智力和对男性和女性吸引力的刻板印象进行讨论。