The habit of drifting off into daydreams seems to run partly in families, and it is already fading by your late twenties. An analysis of nearly 1,200 young American adults found that identical twins were far more alike in how much they daydream than fraternal twins, and that daydreaming was slightly less common with each year of age.
Levana Baranes, Hagar Shimoni and Vadim Axelrod of the Gonda Multidisciplinary Brain Research Center at Bar Ilan University in Israel reported the findings in Current Psychology, published online on August 24, 2024.
One question, answered by 1,194 people
The team did not run a new experiment. They mined the Human Connectome Project Young Adult dataset, a large brain imaging study in which healthy participants also spent hours on behavioral tests at Washington University in St. Louis. After dropping six people with missing data, the sample was 1,194 adults aged 22 to 36, 650 of them women, including 149 pairs of identical twins and 94 pairs of fraternal twins.
Daydreaming was measured with a single item from a standard personality questionnaire: “I don’t like to waste my time day-dreaming.” People who disagreed were scored as more prone to daydreaming.
Age, education and the twin comparison
Older participants reported daydreaming a little less, a weak but statistically reliable correlation of about minus 0.1 that held after accounting for education. The decline is well known in old age; the authors argue their data show it begins much earlier, in line with evidence that some cognitive abilities start to decline around age 20.
More years of education went with more daydreaming, not less, a correlation of about 0.15 after accounting for age. That runs against the common assumption that daydreamers do worse at school. The authors note that the link could run either way: people who daydream may be more likely to pursue education, or education may encourage more inward thinking.
Women and men daydreamed equally, and a Bayesian test supported the conclusion that there was no difference. But the education link was much stronger in women, with a correlation of 0.21, than in men, at 0.08, and that difference between the sexes was significant.
The twin results were the most striking. Identical twins, who share all their genes, correlated at 0.33 in their daydreaming scores, while fraternal twins, who share about half, correlated at 0.12, which was not significant. The standard twin formula put heritability at 0.42. When the researchers randomly paired up 708 unrelated participants 1,000 times, none of those pairings came close to the similarity of identical twins.
The authors acknowledge several limits. The age and education effects were small, explaining only a small share of the differences between people. A single questionnaire item cannot separate pleasant, planning-oriented daydreams from anxious, ruminative ones. And twin studies assume that identical and fraternal twins share their environments to the same degree, which may not always hold. The direct comparison between the two twin correlations also fell just short of significance.
Even fraternal twins stood out from strangers: only 1.4% of the random pairings of unrelated people were as alike in their daydreaming as fraternal twin pairs.
Study Details:
- Title: Demographic and heredity correlates of day-dreaming propensity: insights from the behavioral data of the human Connectome Project Young Adult dataset
- Authors: Levana Baranes, Hagar Shimoni, Vadim Axelrod
- Journal: Current Psychology, Vol. 43, No. 36
- Publication Date: August 24, 2024
- DOI: 10.1007/s12144-024-06541-0