Recent scientific research has illuminated a profound truth about how stress influences human social behavior: While stress may foster unity and generosity among members of the same group, it simultaneously stirs up aggression and suspicion toward those outside the group. These insights, highlighted in a July 2025 report by Psychology Today, draw from a study published in the Proceedings of the National Academy of Sciences (PNAS) and have far-reaching implications for societal cohesion, especially in rapidly changing societies like Thailand.
The crux of the research centers on a question that has puzzled psychologists, sociologists, and even everyday observers for years: Does stress make individuals more aggressive, or does it push them toward cooperation and social bonding? The study, led by a research team using a double-blind, placebo-controlled psychopharmacological experiment, suggests the answer is more complex than previously understood. By investigating the role of the body’s stress-related neurochemicals—specifically cortisol and noradrenaline—the researchers found that stress actually triggers both social bonding with an “us” and antagonism towards a “them,” underscoring what scientists call “parochial altruism” (Psychology Today).
This discovery matters for Thai readers and communities worldwide because it offers a biological blueprint for understanding rising social tensions. As Thailand navigates periods of economic challenge, political shifts, and even public health crises, understanding the neurobiological underpinnings of group behavior can shed light on cultural polarization, political partisanship, and the potential for both collective solidarity and inter-group conflict.
The study’s design was straightforward yet ingenious. Participants, after receiving substances that either increased cortisol or noradrenaline, engaged in a decision-making economic game simulating group conflict and competition for resources. The games allowed choices that could benefit the player personally, aid fellow group members, or harm rival groups—sometimes even at a cost to oneself. Strikingly, increased cortisol levels fostered more generosity and cooperation, but exclusively within one’s own group. Conversely, heightened noradrenaline led to acts aimed at financially damaging outgroup members, even when such acts were personally disadvantageous.
In plain language, this means stress can both help and harm social ties depending on context. When a community faces external pressure—such as an economic downturn, a natural disaster, or even emotive political rhetoric—people may draw closer to their own circles of family, friends, or shared-identity groups. However, that very stress response also sets the stage for viewing outsiders with skepticism, sometimes escalating to open hostility. The phenomenon, known as parochial altruism, has ancient evolutionary roots, serving as a double-edged sword: crucial for group survival in adversity, but also a driver of conflict and tribalism (PNAS, 2025).
An expert in neuropsychology commenting on the results explains: “What this study shows is not just a switch between aggression and cooperation under stress, but a simultaneous activation of both mechanisms. When threatened, we’re wired to help those we perceive as ‘us’ and defend against ‘them’—sometimes aggressively. Understanding this dual response can inform conflict mitigation strategies in multi-ethnic and multicultural societies.”
For Thailand, where social harmony is among the highest cultural values—as encapsulated in concepts like “namjai” (น้ำใจ, generosity of spirit) and “sangkhom” (สังคม, community)—this research bears both a warning and a lesson. While stress can indeed unite families, local communities, or national groups, it can also deepen divides, particularly when coupled with social or online media that amplify “us versus them” narratives. Political figures, policymakers, and educators must therefore remain vigilant against rhetoric or policies that exploit fear and provoke division. Education campaigns and community engagement activities that show the value of diversity, mutual respect, and understanding across cultural lines become even more urgent amidst societal pressures.
Historically, Thailand has navigated its share of group-based tensions, whether rooted in regionalism, ethnicity, or political ideology. The 2010 political protests, prolonged issues in the deep South, and periodic tensions between urban and rural populations all resonate with the study’s findings. These episodes often witness surges in community solidarity among those directly affected, but also outbreaks of mistrust or hostility toward perceived outsiders. Such dynamics are not unique to Thailand—they can be seen from Brexit-era Britain to polarized America—but Thai society’s resilience often comes from its ability to reintegrate and reconcile after conflict.
Looking ahead, global and local changes present fresh challenges. Rising temperatures, pandemic risks, and economic uncertainty are stressors that could fuel both social bonding and, regrettably, greater group antagonism. The study’s authors suggest that recognizing the neurobiological fuel for tribalism can help societies intervene before differences turn into deep rifts. For instance, promoting intergroup cooperation through shared projects, cross-cultural dialogues, and policies that reduce uncertainty for everyone can lessen the “us versus them” impulse.
For Thai readers, this research carries practical takeaways. In times of collective stress—whether during economic downturns, infectious disease outbreaks, or even contentious elections—being aware of our instinctual drives can help us resist divisive narratives. Simple acts—like reaching out to neighbors of different backgrounds, participating in community projects, and seeking out sources that promote understanding rather than fear—can counterbalance the natural but potentially dangerous tendency to circle the wagons. Psychological resilience is built not just by supporting our own but by bridging to others, recognizing common humanity beneath surface differences (Harvard Gazette).
For educators, this means teaching not just academic knowledge but also empathy, cross-cultural communication, and critical thinking so students recognize and challenge “us versus them” thinking. For policymakers and health professionals, fostering inclusive health and welfare policies that do not favor one group over another can prevent the hardening of group lines. For community leaders, organizing inclusive events and dialogues can diffuse tensions before they escalate.
In conclusion, the latest research draws a clear line between our neurobiology and our behavior under pressure. Stress will always be a part of life, but by learning how our brains nudge us toward both helpful and harmful social responses, we can make conscious choices that favor community, inclusion, and peace. For Thai society, drawing on traditions of harmony while remaining vigilant against divisive impulses will be key to meeting the challenges of an increasingly complex world.
For further details, readers can consult the original report in PNAS and the Psychology Today article.