In our Study of the Day feature series, we highlight a research publication related to a John Templeton Foundation-supported project, connecting the fascinating and unique research we fund to important conversations happening around the world.
In 2000, psychologist Eric Turkheimer codified what he described as the “Three Laws of Behavior Genetics,” beginning with the headlining First Law: “All human behavioral traits are heritable.” It was a bracing conclusion, particularly in light of ages of the back-and-forth nature versus nurture debate, but over the past quarter-century new research has generally borne it out.
A new study led by Emily Willoughby of the University of Minnesota Twin Cities surfaces an important and ironic exception to the rule. The team found that people’s beliefs about free will seemed basically unconnected with those of their biological or adoptive parents.
“Unlike the vast majority of traits studied in family designs,” the authors write, “agentic beliefs appear to be weakly or not at all heritable.”
The study surveyed hundreds of families with at least two offspring who were adolescents at the time they were recruited. Of the teenagers, 55 percent were adoptees, all of whom had joined their current families before the age of two. The survey used direct questions and carefully constructed vignettes to suss out people’s beliefs according to various established psychological scales related to free will, including their beliefs about biological, genetic, social, and environmental forms of determinism, fatalism, and general human capacities for learning and growth.
The authors found that, unlike most behavioral traits, beliefs about free will are not particularly influenced by either genes or the shared family environment. This means that even identical twins raised in the same household would have a very low correlation in their agentic beliefs, both with each other and with their parents.
The study’s findings, of course, say nothing about the age-old question of whether free will actually exists, or even whether our beliefs about free will are arrived at freely. Environmental factors and the accumulating effects of each person’s unique life experiences are likely highly influential in how their ideas about determinism develop. Willoughby et al. write:
“If agentic beliefs are largely caused by variation in the non-shared environment, can we infer any specific environmental factors as causes? Unfortunately, the non-shared environment has proven hard to pin down. In behavioral genetics, the phrase ‘gloomy prospect’ refers to the idea that non-shared environmental influences are idiosyncratic events that resist all attempts at systematic measurement, despite being among the causes of individual differences.”
Our opinions about destiny, free will, and personal agency could still have been fated by something, but it does seem like mom and dad are not to blame.
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Nate Barksdale writes about the intersection of science, history, philosophy, faith, and popular culture. He was editor of the magazine re:generation quarterly and is a frequent contributor to History.com.
