20 - Unresolved questions and future directions in behavior-genetic studies of intelligence

Summary

Introduction

Most people seem to feel that the “nature versus nurture controversy,” as it is commonly and unfortunately phrased, is either passe or settled with regard to intelligence. Indeed, Hunt (chapter 19, this volume) was sufficiently moved by the topic to coin a new term, vujà dé, which loosely translated means “get this away from me, I do not ever want to see it again.” Rather than representing a lone dissenting voice, it is my sense that Hunt speaks for the masses, or at least for sizable contingents of researchers who occupy very different positions on the relevant issues. Given this, is there justification for the current collection of chapters on the hereditary and environmental bases of intelligence?

If one views the causal basis of intelligence as a battle or controversy (viz., nature versus nurture), then I agree that there is little justification, as is the case if one views the disentanglement of genetic and environmental influences as an irrelevant or impossible goal. Contrary to the views of many social science researchers, including a number of contributors to this volume, I believe that characterization of the unique and conjoint contributions of genetic and environmental influences to intelligence is a worthwhile and attainable goal. Behavior-genetic designs have been used – successfully, in my opinion – to characterize broad components of variance corresponding to genetic and environmental influences on intelligence.