Link Search Menu Expand Document

Origins of Moral Psychology

Developmental research indicates that developmental origins of moral psychology can be found even in preverbal infants.

If the video isn’t working you could also watch it on youtube. Or you can view just the slides (no audio or video).

This recording is also available on stream (no ads; search enabled).

If the slides are not working, or you prefer them full screen, please try this link. The recording is available on stream and youtube.


moral sense: a ‘tendency to see certain actions and individuals as right, good, and deserving of reward, and others as wrong, bad, and deserving of punishment’ (Hamlin, 2013, p. 186).

Hamlin’s three requirements for having a moral sense:

  • prosociality (helpfulness towards others)

  • discrimination between pro- and anti-social acts

  • retribution

‘infants are making relatively complex and sophisticated social judgments in the first year of life. They not only evaluate others based on the local valence of their behavior, they are also sensitive to the global context in which these behaviors occur. During the second year, young toddlers direct their own valenced acts toward appropriate targets.’ (Hamlin, Wynn, Bloom, & Mahajan, 2011, p. 19933)

‘developmental research supports the claim that at least some aspects of human morality are innate. From extremely early in life, human infants show morally relevant motivations and evaluations—ones that are mentalistic, are nuanced, and do not appear to stem from socialization or morally specific experience’ (Hamlin, 2013, p. 191).

Poverty of Stimulus Arguments

How do poverty of stimulus arguments work? See Pullum & Scholz (2002).

  1. Human infants acquire X.

  2. To acquire X by data-driven learning you’d need this Crucial Evidence.

  3. But infants lack this Crucial Evidence for X.

  4. So human infants do not acquire X by data-driven learning.

  5. But all acquisition is either data-driven or innately-primed learning.

  6. So human infants acquire X by innately-primed learning .

‘the APS [argument from the poverty of stimulus] still awaits even a single good supporting example’ (Pullum & Scholz, 2002, p. 47). Since then (2002), a single example has been found (Lidz, Waxman, & Freedman, 2003). But just one, as far as I can tell (in 2021).


moral sense : A ‘tendency to see certain actions and individuals as right, good, and deserving of reward, and others as wrong, bad, and deserving of punishment’ (J. Kiley Hamlin, 2013, p. 186).


Hamlin, J. K. (2014). Context-dependent social evaluation in 4.5-month-old human infants: The role of domain-general versus domain-specific processes in the development of social evaluation. Frontiers in Psychology, 5.
Hamlin, J. Kiley. (2013). Moral Judgment and Action in Preverbal Infants and Toddlers: Evidence for an Innate Moral Core. Current Directions in Psychological Science, 22(3), 186–193.
Hamlin, J. Kiley, Wynn, K., Bloom, P., & Mahajan, N. (2011). How infants and toddlers react to antisocial others. Proceedings of the National Academy of Sciences, 108(50), 19931–19936.
Lidz, J., & Waxman, S. (2004). Reaffirming the poverty of the stimulus argument: A reply to the replies. Cognition, 93(2), 157–165.
Lidz, J., Waxman, S., & Freedman, J. (2003). What infants know about syntax but couldn’t have learned: Experimental evidence for syntactic structure at 18 months. Cognition, 89(3), 295–303.
Pullum, G. K., & Scholz, B. C. (2002). Empirical assessment of stimulus poverty arguments. The Linguistic Review, 18(1–2).