Milestones in Social Psychology: From Crowd Behavior to Modern Research

Why do people act so differently in a crowd than they do alone? Why would an ordinary person deliver what they believe to be a painful electric shock to a stranger – simply because someone in a lab coat told them to? These aren’t idle philosophical questions. They’re the kinds of puzzles that gave birth to social psychology as a scientific discipline. The story of how social psychology evolved – from early observations of crowd behavior to tightly controlled laboratory experiments – is one of the most intellectually compelling journeys in modern science.

The early roots: observing the crowd 🔗

Before social psychology had laboratories, controlled trials, or even a formal name, it had observers. Among the earliest and most influential was the French physician and sociologist Gustave Le Bon. In 1895, he published his landmark work The Crowd: A Study of the Popular Mind, a book that attempted to explain the psychological forces driving collective behavior. Le Bon had witnessed firsthand the turbulent mass movements of 19th-century France, and he was convinced that something fundamentally changed when individuals merged into a crowd.

According to Le Bon, crowds are not simply the sum of their individual parts – within them, a new psychological entity forms, with its own characteristics. He argued that individuals immersed in a crowd could lose their sense of personal identity and rational thought, becoming susceptible to suggestion and emotional contagion. Le Bon theorized that this “crowd mind” spread rapidly through a group, making it vulnerable to manipulation by a charismatic speaker – a process he compared to hypnotic suggestion. His work, translated into nineteen languages within a year of publication, would go on to influence figures from Sigmund Freud to, more troublingly, Adolf Hitler.

Le Bon’s contribution, while later critiqued for lacking rigorous empirical methods and for its politically conservative framing, was foundational. It raised questions about how social contexts transform individual behavior – questions that would drive researchers for the next century.

The first experiment: Norman Triplett and social facilitation 🔗

While Le Bon theorized about crowds, it was Norman Triplett who brought social psychology into the laboratory. In 1897, Triplett – an American psychologist at Indiana University – published what is widely regarded as the first empirical study in social psychology. His experiment was elegantly simple: he asked children to wind a fishing reel as fast as possible, either alone or alongside other children doing the same task. The results were clear – children worked faster in the presence of peers than when alone.

Triplett had been inspired by an earlier observation: cyclists consistently rode faster when racing against other riders than when racing against the clock. This led to the concept of social facilitation – the finding that the mere presence of others can enhance an individual’s performance on a task. The experiment marked a historic turning point: it formally introduced the experimental method into the social sciences. Rather than philosophical speculation, social psychology now had data.

It’s worth noting that Triplett’s work was later extended by Floyd Allport, who in 1920 coined the term “social facilitation” and refined the experimental controls of the time. Allport is often described as the founder of experimental social psychology, and his 1924 textbook Social Psychology is widely credited with marking the beginning of the modern period of the discipline.

The field takes shape: early 20th-century formalization 🔗

By 1908, social psychology was formal enough to have its first textbooks. William McDougall and Edward Alsworth Ross independently published the first social psychology textbooks that year, each approaching the subject from different angles – McDougall from an instinct-based perspective, Ross from a sociological one. These texts signaled that social psychology was no longer a fringe curiosity. It was a recognized discipline with a growing body of knowledge.

The interwar period brought new intellectual energy. Kurt Lewin, a German-Jewish psychologist who fled Nazi Germany in the 1930s, became one of the most influential figures in the field. Lewin is sometimes referred to as “the father of social psychology” because he developed many of the discipline’s foundational ideas, including an emphasis on the dynamic, ongoing interactions among people and their environments. His focus on group dynamics and field theory gave researchers new tools for understanding how social situations shape behavior.

Muzafer Sherif and the birth of social norms research 🔗

In the early 1930s, Muzafer Sherif stepped onto the scene with a deceptively simple experiment that would reshape thinking about social norms. Sherif was skeptical of the prevailing view – championed by Allport – that a group was merely a collection of individuals. He believed that groups created something more: shared realities that shaped perception itself.

To test this, Sherif used the autokinetic effect – a visual illusion in which a small, stationary point of light in a completely dark room appears to move. When participants were placed in groups and asked to estimate the light’s movement out loud, their individual judgments gradually converged over repeated trials. Groups naturally settled on a shared “social norm” of perception – without any instruction or discussion about reaching agreement. When those same participants were later tested alone, they continued to use the group’s estimate as their reference point, suggesting they had genuinely internalized the shared norm rather than simply complying with group pressure in the moment.

This was a pivotal finding. It showed that social norms don’t just constrain behavior from the outside – they become part of how individuals perceive and interpret the world. Sherif’s experiment demonstrated that in ambiguous situations, people look to others for informational guidance, and the resulting shared perceptions can persist long after the group interaction ends. His 1936 book, The Psychology of Social Norms, formalized these ideas and set the stage for decades of research on conformity and group influence.

Solomon Asch and the power of group pressure 🔗

Sherif’s experiment studied conformity under ambiguous conditions. But what about situations where the correct answer is objectively obvious? That’s where Solomon Asch made his mark. In 1951, Asch conducted one of social psychology’s most replicated and revealing studies at Swarthmore College.

Asch recruited 50 participants for what they believed was a vision test. Each real participant was placed in a group with seven confederates – individuals who secretly worked with the experimenter. The task was simple: compare a reference line to three other lines and identify which one matched in length. The answer was always unambiguous. But on critical trials, all seven confederates gave the same wrong answer – and the real participant had to respond last.

The results were striking. Across 18 trials, the confederates gave incorrect answers 12 times. Three-quarters of the real participants conformed to the wrong answer at least once. When interviewed afterward, participants explained their conformity in two main ways: some genuinely doubted their own perception when faced with a unanimous group; others knew the group was wrong but went along to avoid standing out. Asch’s work is said to have had a profound impact on how psychologists think about and study social influence in groups.

His research drew an important distinction between two forces driving conformity: informational influence (changing one’s belief because the group seems to have better information) and normative influence (changing one’s behavior to fit in and avoid social rejection). Both are still central concepts in social psychology today.

Stanley Milgram and obedience to authority 🔗

If Asch showed that people conform to peer pressure, Stanley Milgram revealed something even more unsettling: ordinary people will obey authority figures even when doing so means potentially causing serious harm to another person.

Milgram was directly motivated by the horrors of the Holocaust and the question raised by philosopher Hannah Arendt about the “banality of evil.” He began his experiments in July 1961, shortly after the conclusion of the Adolf Eichmann trial in Jerusalem, asking: could the genocide carried out by Nazi officers be explained simply by obedience to authority rather than by exceptional cruelty or ideology?

In Milgram’s experiment, participants were told they were taking part in a study on learning and memory. They were assigned the role of “teacher” and instructed by an authoritative experimenter to administer electric shocks to a “learner” (actually an actor) each time the learner gave a wrong answer – with the shocks increasing in intensity up to a level labeled “Danger: Severe Shock.” Despite the learner’s apparent distress, a significant portion of participants continued administering shocks when the experimenter calmly instructed them to continue. Milgram’s research showed that many people in the experiment obeyed the experimenter’s order to give potentially dangerous levels of electric shock to a stranger.

The findings were deeply disturbing and generated significant ethical debate. But they also delivered an essential message: even ordinary people who are neither bad nor evil can be placed in situations where an authority figure leads them to engage in harmful behaviors. The situation, not just the person, is a powerful driver of behavior. Milgram’s work is still considered one of the most inspired contributions in the field of social psychology.

Post-war expansion and the cognitive turn 🔗

The post-war period saw social psychology expand rapidly. Researchers turned their attention to topics like prejudice and intergroup conflict. Gordon Allport‘s 1954 book The Nature of Prejudice became a cornerstone text, analyzing the psychological roots of discrimination and stereotyping. That same year, social psychologists contributed expert testimony to the U.S. Supreme Court’s landmark Brown v. Board of Education case, which ended racial segregation in public schools – a striking demonstration of the field’s real-world relevance.

During the 1940s and 1950s, Kurt Lewin and Leon Festinger refined the experimental approach to studying behavior, pushing for more rigorous methods and the careful measurement of variables. Festinger’s theory of cognitive dissonance – the discomfort caused by holding conflicting beliefs – became one of the most studied phenomena in the field. Meanwhile, researchers like John Darley and Bibb Latané developed models explaining when and why people help others in need, and Irving Janis examined why intelligent groups sometimes made catastrophically poor decisions – a phenomenon he called groupthink.

What these milestones tell us 🔗

Taken together, the trajectory from Le Bon’s crowd observations to Milgram’s obedience experiments reveals a central and enduring insight: the social situation is often a stronger determinant of behavior than individual personality. People don’t behave the same way in isolation as they do in groups. They conform, obey, and internalize norms – often without realizing it. The early researchers of social psychology didn’t just describe these phenomena; they designed experiments that made these invisible social forces visible.

What began as Le Bon’s philosophical observation about mobs in 19th-century Paris grew into a rigorous, experimentally grounded science that continues to illuminate why humans behave as they do in social contexts – from workplaces and classrooms to online communities and political movements. Each milestone in this history didn’t just answer a question. It opened up new ones.

What do you think? Sherif showed that people adopt group norms even in genuinely ambiguous situations – but how does this play out when group norms are harmful or factually wrong? And given what Milgram revealed about obedience to authority, what does it take for individuals to resist unjust instructions from those in power?

References

1. https://en.wikipedia.org/wiki/Gustave_Le_Bon
2. https://www.mediastudies.press/pub/emet-le-bon-crowd
3. https://en.wikipedia.org/wiki/The_Crowd:_A_Study_of_the_Popular_Mind
4. https://psychology.iresearchnet.com/social-psychology/history-of-social-psychology/
5. https://formalpsychology.com/history-of-social-psychology/
6. http://www.noeticmind.org/studies/historical-reference-of-social-psychology.htm
7. https://opentextbc.ca/socialpsychology/chapter/defining-social-psychology-history-and-principles/
8. https://en.wikipedia.org/wiki/Muzafer_Sherif
9. https://www.zimbardo.com/the-autokinetic-effect-study-sherif-setup-results-and-psychological-insights/
10. https://en.wikipedia.org/wiki/Social_experiment
11. https://empowercommunityhealth.org/social-psychology-2/
12. https://socialsci.libretexts.org/Courses/Coalinga_College/Personal_Psychology__(C-ID_PSY_115_Psychology_of_Personal_and_Social_Adjustment)/06:_Social_Psychology/6.02:_The_History_of_Social_Psychology