A 2001 study published in the Journal of Personality and Social Psychology by LeeAnne Harker and Dacher Keltner suggests that genuine, “Duchenne” smiles in college yearbook photos correlate with higher life satisfaction and more stable marriages up to 30 years later. The research, which analyzed the Mills Longitudinal Study, indicates that these expressions serve as early, involuntary indicators of underlying personality traits rather than causes of future success.
The Science of the Duchenne Smile
The distinction between a posed smile and a genuine one lies in human anatomy. According to research by Harker and Keltner, a Duchenne smile—named after a nineteenth-century French physician—engages two specific muscle groups. The zygomatic major lifts the corners of the mouth and can be activated voluntarily via the motor cortex. Conversely, the orbicularis oculi, which creates the characteristic crinkles around the eyes, is largely involuntary and controlled by the brain’s limbic system.
Because the orbicularis oculi is difficult to trigger on command, its presence in a photograph acts as a marker for genuine positive emotion. In the Mills College cohort, women who displayed these crinkles in their senior portraits reported higher levels of well-being and more stable marriages when reassessed at ages 27, 43, and 52.
Did you know?
The Duchenne smile is considered a “limbic” expression because it is a physiological response that happens to a person when they feel genuine emotion, rather than a motor-cortex action they perform for an audience.
Limitations and the Problem of Replication
While the Mills College findings are frequently cited, they are confined to a specific demographic: women who attended a private, predominantly white, middle-class college in the late 1950s. As noted by the researchers, these results do not imply that smiling causes a better life. Instead, the expression reflects a pre-existing disposition toward warmth and ease in social interactions.
Attempts to apply this model to broader populations have yielded mixed results. In 2007, researchers Jeremy Freese, Sheri Meland, and William Irwin applied the same methodology to the Wisconsin Longitudinal Study. Their findings, published in the Journal of Research in Personality, failed to replicate the original results, highlighting that the predictive power of a yearbook photo is limited by social, cultural, and generational factors.
Can We Read Character Through Portraits?
A yearbook portrait is a highly constructed social performance. Subjects choose their attire, pose, and expression to curate a specific image for their peers. Despite this, the Harker and Keltner study suggests that involuntary physiological cues—the “crinkling” of the eyes—can bypass this construction, offering a glimpse into a person’s habitual way of being.
This suggests that human perception of character is often based on subtle, rapid judgments. When individuals exhibit a genuine smile, they often elicit warmer responses from others. Over decades, these small, reinforcing social interactions can compound, potentially influencing the quality of a person’s long-term relationships and professional life.
Pro Tip:
Avoid interpreting a lack of a Duchenne smile in a photograph as a predictor of poor life outcomes. The Mills study focused on population averages and does not account for individual circumstances, personality types, or the context of the era in which the photo was taken.
Frequently Asked Questions
Does forcing a smile in photos improve your future?
No. The study by Harker and Keltner does not suggest that “practicing” a smile will change your life trajectory. The genuine smile is an indicator of an underlying personality trait, not a cause of life events.
Why did the Wisconsin study fail to replicate the Mills results?
The Wisconsin study used a larger, more socially diverse sample than the Mills Longitudinal Study. The discrepancy suggests that the original findings may be specific to the cultural norms and social environment of the 1950s.
Is the Duchenne smile the only indicator of character?
No. While the Duchenne smile is a measurable marker of positive expressivity, it is only one piece of a complex puzzle. Personality, social background, and life circumstances play far larger roles in shaping long-term well-being.
What are your thoughts on the readability of facial expressions? Do you believe our “habitual” expressions are visible to others before we even speak? Share your insights in the comments section below.
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