Response Bias Is Genetically Biased: Another Argument for Kagan's Philippic Against Questionnaires in Developmental Psychology

One of the concerns of Jerome Kagan (2007) in his article "A Trio of Concerns" was the frequent use of questionnaires in developmental psychology and related disciplines. His main reasons were the minimal overlap between (self-)reported and observed phenotypes, the ambiguity of items, and systematic socioeconomic status (SES) disparities in responding. We wondered whether genetic differences would also influence response bias in cases of ambiguous or even absurd items triggering an acquiescence bias to agree with even impossible question content. We examined the genetic predisposition for the acquiescence response bias in 257 families with twins. Both parents and twins completed a modified Wildman Symptoms Questionnaire and provided salivary DNA samples. From published genome-wide association studies (GWAS), we derived polygenic score (PGS) algorithms for indicators of SES (educational attainment [EA] and income) and for general intelligence (IQ), which were applied to the GWAS results of our participants' DNA. The twins (N = 514 children, 55% monozygotic pairs) were on average 7.92 years old (SD = 0.66), and 51.6% were female. The primary parents were on average 40.48 years old (SD = 4.66), and 91% were female. In 90% of the families, both parents were born in the Netherlands and 91% were from a middle or higher socioeconomic background. Higher PGSs for EA and income but not for IQ predicted less acquiescence response bias in parents and children. In addition to Kagan's reasons for his concerns about questionnaires, we found a genetic predisposition to response bias triggered by the ambiguous form of questions and answers.