Cohort effects in children's delay of gratification.
Level 3 - non-randomized controlled study
Cross-temporal cohort analysis of historical and modern experimental data (by design analogy, not clinical CEBM)
PubMed 29939038 · doi:10.1037/dev0000533
What was done
Study 1 surveyed U.S. adults (N = 354, median age 34 years) to assess common intuitions about temporal trends in children's self-control. Study 2 analyzed original experimental data comparing average delay-of-gratification times (out of 10 minutes) in 840 typically developing U.S. children aged 3 to 5 years from similar middle-to-high socioeconomic backgrounds across three birth cohorts: the late 1960s, 1980s, and 2000s.
What was found
Although surveyed adults anticipated a decline in children's patience, delay times demonstrated a statistically significant linear increase over time (p < .0001, ηp² = .047). Children tested in the 2000s waited an average of 2 minutes longer than those tested in the 1960s and 1 minute longer than those tested in the 1980s. This cohort pattern remained robust across age, sex, geography, and sampling effects.
Why it matters
These findings directly challenge the pervasive assumption that modern children have worse impulse control, showing instead a secular rise in delay ability across four decades.
Limits
The findings are limited to typically developing U.S. children from middle-to-high socioeconomic backgrounds, precluding generalization to broader or lower-SES populations. As an observational cohort comparison, the study cannot confirm the specific causal drivers (such as increased technology, preschooling, or executive function focus) of the observed increase.
Cited by
- contradicts In the original Stanford marshmallow experiment, no child was able to wait the full 15 minutes to receive the second marshmallow without eating the first.