Are Babies Born Moral? A Landmark Study Challenges Our Understanding of Infant Ethics

Thursday, February 6, 2025.

For centuries, philosophers and psychologists have pondered the nature of morality. Are we born with an intrinsic sense of right and wrong, or do we learn it through experience?

A groundbreaking study in 2007 by Kiley Hamlin and her colleagues seemed to tilt the scales toward the idea that even infants possess a moral compass.

However, a massive recent replication effort by the ManyBabies consortium has cast doubt on this cherished notion. Could it be that babies are, after all, moral blank slates?

The Magic of Early Morality: A Landmark Study

Imagine a six-month-old baby, wide-eyed and full of wonder, watching a simple puppet show.

In the original study, researchers presented infants with a scene in which a character—a simple shape with googly eyes—struggled to climb a hill.

In some trials, another character came along to help; in others, a different character pushed the climber down. When given the chance to choose, a remarkable 88% of ten-month-olds and 100% of six-month-olds reached for the helper.

This finding is potentially electrifying.

It suggested that moral preference—the ability to distinguish between prosocial and antisocial behaviors—wasn’t something learned over time but something we are born with.

The study became a cornerstone in developmental psychology, fueling discussions about innate morality, the evolution of prosocial behavior, and even the philosophical implications of human nature.

Cracking the Code: A Larger Test

But good science thrives on replication.

The ManyBabies project—a global network of developmental researchers—set out to rigorously test these early findings.

Instead of testing a handful of infants, they gathered data from an astonishing 567 babies across 37 labs spanning five continents.

Instead of using a live puppet show, the researchers standardized the experience by presenting a video version of the experiment.

The result? Unlike Hamlin’s original findings, the infants in the replication study did not show a consistent preference for the helper. The moral intuition that seemed so evident in the original study was nowhere to be found.

Does This Mean Babies Are Blank Slates?

This new finding reignites one of the most enduring debates in philosophy and psychology.

In the 17th century, John Locke famously described the human mind as a "tabula rasa"—a blank slate upon which experience inscribes knowledge and morality. If babies truly lack an innate moral sense, does this mean Locke was right all along?

Not necessarily.

Replication failures don’t always mean the original study was wrong; they often reveal the complexity of the phenomenon being studied. Previous replications of the helper-hinderer study have yielded mixed results—some confirming Hamlin’s findings, others not.

Subtle differences in how experiments are conducted can dramatically impact outcomes. For example, one failed replication was later attributed to the googly eyes on the characters not being positioned quite right.

In the ManyBabies replication, the transition from a live puppet show to a digital video format was a significant methodological shift. Research suggests that infants engage with live demonstrations differently than with videos (Barr, 2010). Could this difference have influenced the results?

Additionally, other studies continue to support the idea that infants have early moral intuitions. For example, Bloom (2013) and Warneken & Tomasello (2006) have found evidence of prosocial behaviors in young children, such as spontaneous helping and fairness preferences.

Where Do We Go From Here?

Michael Frank, a leading voice in the ManyBabies consortium, urges caution in interpretation. “Some people will jump to the conclusion that this means the original finding was incorrect.

But we shouldn’t be so quick to jump to the conclusion that this means the original finding was incorrect. But we shouldn’t be so quick to jump to conclusions.”

Instead, this study serves as a reminder that the search for truth in developmental science is ongoing.

Babies might not be moral blank slates, but their moral development may be more context-dependent than we previously believed.

Perhaps morality emerges through interactions with caregivers, or maybe different moral instincts develop at different times.

As more replications and refinements emerge, we’ll get closer to understanding the origins of human morality.

For now, the debate remains open, and the mystery of infant morality continues to captivate the scientific world.

Be Well, Stay Kind, and Godspeed.

REFERENCES:

Barr, R. (2010). Transfer of learning between 2D and 3D sources during infancy: Informing theory and practice. Developmental Review, 30(2), 128-154.

Bloom, P. (2013). Just Babies: The Origins of Good and Evil. Crown.

Hamlin, J. K., Wynn, K., & Bloom, P. (2007). Social evaluation by preverbal infants. Nature, 450(7169), 557-559.

Warneken, F., & Tomasello, M. (2006). Altruistic helping in human infants and young chimpanzees. Science, 311(5765), 1301-1303.