Why are some of us easily affected by the majority's action whereas others frequently make unique choices? In this behavioral genetic study on conformity,we designed a social episode to investigate the genetic and environmental origin of individual differences in conforming behavior during psychosocial development.Specifically,107 monozygotic(MZ) and 74 dizygotic(DZ) twin pairs(age 7-19) were asked to choose a pen from a group of pens either with the majority color or with the minority color.We found that the resemblance between MZ twins in selecting the pen with the majority color was not significantly higher than that between DZ twins,suggesting that individual differences in conformity are due almost exclusively to the environment.Moreover,biometric model fitting revealed that the shared environmental component played a sizable role in shaping individuals' conforming behavior,and the influence increased with age(from 16% to 26%).Taken together,our study suggests that the common family and cultural environment has important ramifications for conformity.
The concept of self is a fundamental characteristic of the human mind,and the alteration of self is thought to be a core deficit of schizophrenia.Previous studies have demonstrated that patients with schizophrenia are deficient in self-face recognition.Because self faces are not only self-related but also highly familiar,it is unclear whether such deficit arises from the breakdown of the self-awareness or the failure of recognizing the familiarity of self faces.Here we directly tested these two alternatives by instructing patients with schizophrenia to recognize the identity of a morphed face created by blending face features between any of two identities from the self face,a familiar face,and a novel face.We found that there was no association between the recognition of the self and the recognition of the familiarity,suggesting these two component processes are independent in schizophrenia.Further,patients with schizophrenia were significantly worse in recognizing the familiarity of faces than normal participants,whereas no difference in the sense of self was found between the two groups.Taken together,our finding suggests that it is the sense of familiarity,not the sense of self,that is selectively impaired in self-face recognition in schizophrenia.Thus,our study challenges the hypothesis that the deficit in self-face recognition in schizophrenia reflects the breakdown of self-awareness.
Deficits in social communication are one of the behavioral signatures of autism spectrum disorder(ASD). Because faces are arguably the most important social stimuli that we encounter in everyday life, investigating the ability of individuals with ASD to process faces is thought to be important for understanding the nature of ASD. However, although a considerable body of evidence suggests that ASD individuals show specific impairments in face processing, a significant number of studies argue otherwise. Through a literature review, we found that this controversy is largely attributable to the different face tests used across different studies. Therefore, a more reliable and valid face test is needed. To this end, we performed a meta-analysis on data gleaned from a variety of face tests conducted on individuals with developmental prosopagnosia(DP) who suffer a selective deficit in face processing. Based on this meta-analysis, we selected an old/new face recognition test that relies on face memory as a standard diagnostic test for measuring specific face processing deficits. This test not only reliably reflects DP individuals' subjective experiences with faces in their daily lives, but also effectively differentiates deficits in face processing from deficits caused by other general problems. In addition, DP individuals' performance in this test predicts their performance in a variety of face tests that examine specific components of face processing(e.g., holistic processing of faces). Finally, this test can be easily administrated and is not overly sensitive to prior knowledge. In summary, this test can be used to evaluate face-processing ability, and it helped to resolve the controversy whether individuals with ASD exhibit face-processing deficits.
