心理与脑科学研究中的样本代表性

Sample representativeness in psychological and brain science research

心理与脑科学以人类被试作为研究对象,其结果的可推广性(generalizability,也称为普适性)很大程度上取决于其样本的代表性(representativeness).但心理与脑科学研究中样本的代表性长久以来饱受诟病.当前研究中主要存在两大问题:(1)样本信息的缺失,大部分研究仅报告了被试的性别、年龄与国别,而被试的种族/民族、受教育程度和社会经济地位等重要信息较少被报告,且从时间跨度上看,这种状况较以前未得到根本性改变;(2)从已报告的信息来看,当前样本的代表性不足:女性被试多于男性,集中于西方的、年轻的和受过高等教育的人群,而中老年人、受教育水平较低人群及低收入人群较少被研究者关注,亚洲人/亚裔、黑人/非洲裔、西班牙裔/拉丁裔人群同样较少受到关注,从国别角度来说,亚非拉国家尤其是非洲、拉丁美洲与中东地区的人群较少出现在心理和脑科学研究中.以上两大问题的产生可能主要存在如下原因:方便取样法作为主要的取样方法;欧美研究者主导了心理与脑科学的研究;整体上忽视文化以及不同人口因素的影响;研究者自身存有偏见.要改变这种现状,需要研究者、学术组织、期刊编辑和基金资助方等多方的共同努力.提升样本代表性将有助于让心理与脑科学的科学知识应用于更广泛的群体,推动人类命运共同体的构建.

Psychological and brain science explore human behavior and the human brain by studying volunteers who participate in these studies.Given that the minds and behavior of participants are influenced by their own biological and social factors,the generalizability of findings in these fields largely depends on the representativeness of samples.However,the representativeness of samples in psychological and brain science has long been criticized as“WEIRD”(Western,Educated,Industrialized,Rich,and Democratic).In recent years,several meta-researches have surveyed the representativeness of samples in published studies from different sub-fields,but an overall understanding of the representativeness of samples in psychological and brain science is lacking.In this review,we analyze these meta-researches to provide a comprehensive perspective on the current state of sample representativeness.Two common issues emerged across these meta-researches.Firstly,the demographics of participants were incomplete in most of the published studies.Most psychological and brain science studies reported participants′gender,age,and country,but participants′race/ethnicity,education level,and socioeconomic status were far less reported.Other important demographics,such as rural/urban division,were not reported at all.Additionally,the reporting of these demographics has increased only slightly in recent years compared to decades ago.Thus,the under-reporting of demographic information in literature was largely unchanged.Secondly,based on the reported demographics,we found that samples in the field are far from being representative of the world population:most participants are young,highly educated Caucasian females in Western countries;middle-aged and older,less educated,colored people in and outside Western countries are less likely to be studied.In terms of countries,Southeast Asian,African,Latin American,and Middle Eastern countries appear fewer in psychological and brain science research.These two issues may be due to the following reasons:Convenience sampling dominates psychological and brain science;Western researchers dominate the field of psychology and brain science,with most of the editors-in-chief,editorial board members,and authors coming from Europe and America;psychology and brain science undervalued the effect of socioeconomic and cultural factors;and researchers mistakenly believe that findings from Western participants can be generalized to all human beings.Addressing the issue of sample representativeness in psychological and brain sciences requires a concerted effort by researchers,academic societies,journals,and funding agencies:Researchers should collect and report detailed demographic information about participants,state the limitations of generalizability,and use sampling methods that can increase representativeness whenever possible(e.g.,probability sampling);academic societies should pay attention to the representativeness issues by organizing more academic symposium or workshops on this topic;journals should increase the representativeness of editorial board members and encourage more rigorous research with samples from underrepresented groups or studies that examine the generalizability of important findings;funding agencies can encourage researchers to pay more attention to study groups from underrepresented countries,and provide financial support for studying hard-to-research population.Improving sample representativeness will enhance the value of applying psychological and brain science knowledge in real-life settings and promote the building of a community with a shared future for mankind.