The Psychology of Influence

The psychology of influence is the study of how other people, messages and situations change our attitudes, beliefs and behavior. It covers everything from quietly copying what a group does, to agreeing to a salesperson's request, to following an order from someone in authority. Most of it sits within social psychology, with important contributions from cognitive psychology and behavioral economics.

Influence is not inherently sinister. Teachers, doctors, public health campaigns and friends all influence us, often for the better. The same mechanisms, however, can be exploited, so understanding them is useful both for communicating clearly and for recognizing when you are being pushed.

What Is Social Influence?

Social influence is any change in a person's thoughts, feelings or actions caused by the real or imagined presence of others. Psychologists usually describe three broad forms, which differ in how direct the pressure is.

Why we go along: informational and normative influence

Morton Deutsch and Harold Gerard (1955) distinguished two motives. Informational influence happens when we treat other people's behavior as evidence about reality: if everyone is leaving a building, there is probably a reason. Normative influence happens when we go along to be liked or to avoid rejection, even if we privately disagree. Informational influence tends to produce genuine private acceptance; normative influence often produces public agreement only.

Depth of change: Kelman's three processes

Herbert Kelman (1958) added that influence can run at different depths. Compliance is going along to gain a reward or avoid punishment, and it fades when nobody is watching. Identification is adopting a view because you want to be like a person or group you admire. Internalization is accepting a view because it fits your own values, and it is the most durable. This framework helps explain why pressure tactics often produce short-lived results.

Landmark Studies of Conformity and Obedience

In Asch's conformity experiments, participants judged which of three lines matched a target line after hearing several confederates give an obviously wrong answer. Across the critical trials, participants went along with the wrong majority roughly a third of the time, and about three-quarters conformed at least once. When just one other person broke from the majority, conformity dropped sharply, showing how much a single ally matters.

In the Milgram experiment, 26 of 40 participants (65%) in the best-known condition continued to the maximum 450-volt level when instructed by an experimenter, although the shocks were not real. Obedience fell when the experimenter gave orders by telephone or when the learner was in the same room. Later scholarship, including archival work by Gina Perry and analyses by Alex Haslam and Stephen Reicher, has questioned how consistently procedures were followed and argued that participants were often identifying with the scientific project rather than obeying blindly. Jerry Burger's 2009 partial replication, stopped at 150 volts for ethical reasons, found rates broadly similar to Milgram's.

Influence also runs the other way. Serge Moscovici's research on minority influence (1969) showed that a consistent, confident minority can gradually shift a majority's judgments, usually by prompting people to think more deeply rather than by social pressure.

Cialdini's Seven Principles of Influence

Social psychologist Robert Cialdini spent years studying both laboratory findings and real-world "compliance professionals" such as salespeople, fundraisers and recruiters. In Influence (1984) he grouped their techniques into six principles, later adding a seventh, unity. Each works because it usually leads to good decisions; problems arise when the cue is faked.

1. Reciprocity

People feel obliged to return favors. In a classic study by Dennis Regan (1971), participants who received an unexpected soft drink from a confederate later bought more raffle tickets from him than those who received nothing. Free samples and small gifts in charity mailings rely on the same norm. A fair defense is to accept genuine gifts graciously while recognizing that a gift designed as a sales tool does not create a real debt.

2. Commitment and consistency

Once people take a stand, especially a public or written one, they tend to act in line with it. This connects to cognitive dissonance: inconsistency between beliefs and actions is uncomfortable. The foot-in-the-door technique, in which a small request paves the way for a larger one, is the best-known application. Used ethically, written goals and public pledges help people follow through on intentions they already hold.

3. Social proof

When unsure, we look at what similar others are doing. In hotel field experiments by Goldstein, Cialdini and Griskevicius (2008), a card saying most guests reused their towels increased reuse compared with a standard environmental message, and the effect was stronger when the norm referred to guests who had stayed in the same room. Social proof is a form of informational influence; it becomes manipulative when reviews or popularity counts are fabricated.

4. Authority

We tend to defer to people who appear to be experts or who hold legitimate power. Titles, uniforms and confident delivery all signal authority, which is why Milgram's findings remain relevant. Deferring to real expertise is usually sensible; the useful questions are whether this person is a genuine expert on this specific topic and whether they have something to gain.

5. Liking

We are more easily persuaded by people we like, and we tend to like people who are similar to us, who compliment us and who cooperate with us. Physical attractiveness can also create a halo effect, in which one positive trait colors overall judgments. Separating your feelings about the messenger from the merits of the offer is the main safeguard.

6. Scarcity

Things seem more valuable when they are rare or disappearing. In one study, people rated cookies from a jar with two cookies as more desirable than identical cookies from a jar with ten (Worchel, Lee and Adewole, 1975). Scarcity also triggers psychological reactance, the urge to restore a freedom that seems threatened (Brehm, 1966). Countdown timers and "only two left" banners exploit this, sometimes falsely.

7. Unity

Added in Pre-Suasion (2016), unity refers to shared identity: we are more open to influence from people we see as "one of us", such as family, compatriots or members of the same community. It overlaps with research on in-group bias and helps explain the persuasive pull of brand communities and social movements.

How Persuasion Works: Two Routes

Richard Petty and John Cacioppo's elaboration likelihood model (ELM) proposes that persuasive messages are processed along two routes. On the central route, people who are motivated and able to think carefully weigh the quality of the arguments. On the peripheral route, people who are distracted, rushed or uninterested rely on cues such as the speaker's attractiveness, the number of arguments, or how many others agree. Shelly Chaiken's heuristic-systematic model makes a similar distinction.

The practical lesson is that attitudes formed through careful thought tend to last longer and better predict behavior, while peripheral-route change is easier to produce but more fragile. Cialdini's principles mostly operate as peripheral cues, which is why they are most powerful when people are tired, hurried or overloaded.

Cognitive Biases That Make Influence Possible

Many influence techniques work by leaning on predictable cognitive biases, the mental shortcuts that usually help us decide quickly.

• Anchoring: an initial number, such as a high "original price", pulls later estimates toward it, even when the anchor is arbitrary.
• Framing: the same facts feel different when described as gains or losses; "90% survival" sounds better than "10% mortality".
• Confirmation bias: messages that fit what people already believe are accepted with less scrutiny.
• Availability: a vivid story is often more persuasive than accurate statistics because it comes to mind easily.
• Mere exposure: repeated exposure to a name, face or slogan tends to increase liking for it.

Earlier versions of this page listed "behavioral priming" as a reliable technique. Many well-known behavioral priming findings, such as walking more slowly after reading words about old age, have failed to replicate, so they should not be treated as established tools of influence.

Influence in the Digital Age

Online environments concentrate several influence principles at once. Like counts and follower numbers are instant social proof; influencers build a sense of liking and unity through parasocial relationships; limited-time offers deliver scarcity on demand. Recommendation algorithms can amplify content that provokes strong emotion, which may narrow what people see.

Choice architecture and nudges

Richard Thaler and Cass Sunstein popularized the term nudge for changes in how choices are presented that steer behavior without removing options. Defaults are the clearest example: Johnson and Goldstein (2003) showed that European countries with opt-out organ donation systems had far higher registered consent rates than opt-in countries. Nudges can serve people's own goals, such as automatic pension enrollment, but the same design tools can become "dark patterns" when they hide costs, make cancelling difficult, or pre-tick boxes people would not choose.

Misinformation and inoculation

William McGuire's inoculation theory (1960s) proposed that exposing people to a weakened version of a persuasive attack, along with a rebuttal, builds resistance, much as a vaccine does. Modern "prebunking" research applies this to misinformation by teaching people to recognize common techniques such as emotional language, false dichotomies and fake experts. Studies generally find modest but real improvements in spotting manipulative content.

When Influence Becomes Manipulation

Popular writing often uses the label "dark psychology" for manipulative tactics in relationships and groups. These are not formal psychological constructs, but recognizing the patterns can help people understand their experiences. For a fuller treatment, see our guide to manipulation and dark psychology.

• Gaslighting: repeatedly denying or distorting events so that the other person doubts their own memory and judgment.
• Love bombing: intense early attention and affection that creates a sense of obligation and speeds up commitment.
• Intermittent reward: alternating warmth and coldness, which can make approval feel more valuable, echoing findings on intermittent reinforcement in operant conditioning.
• Triangulation: bringing a third person into a conflict to create jealousy or avoid direct communication.

Anyone who feels persistently controlled or unsafe in a relationship deserves support; talking with a trusted person or a qualified professional can help, and urgent situations should be directed to crisis resources.

Ethical Influence Guidelines

Professional codes in marketing, medicine and research all wrestle with the line between persuasion and exploitation. A few principles appear repeatedly:

• Truthfulness: the claims, reviews, deadlines and credentials you use are real.
• Transparency: the audience can see who is asking and why.
• Respect for autonomy: people can say no without penalty, and "no" is accepted.
• Mutual benefit: the outcome serves the person being influenced, not only the influencer.
• Extra care with vulnerable groups: children, people in crisis and people with limited information deserve stronger protections.

Building Resistance to Unwanted Influence

Because influence often works through fast, automatic thinking, the most reliable defenses create space for slower thinking. Daniel Kahneman's distinction between fast and slow thinking, described in our page on Daniel Kahneman, is a helpful lens here.

1. Notice the trigger. Pressure to decide now, an unexpected gift, flattery or an appeal to "people like you" are cues to slow down.
2. Delay important decisions. Even a short pause lets the central route catch up with the peripheral one.
3. Separate the messenger from the message. Ask whether you would accept the same offer from someone you did not like or admire.
4. Check claims independently. Look for the original source of statistics, reviews or expert endorsements.
5. Ask a trusted outsider. Someone not caught up in the situation is less exposed to the same pressures.

These habits draw on critical thinking skills that improve with practice.

Applications Across Domains

Influence research is applied well beyond sales. In public health, social-norm messages and default options have been used to encourage vaccination, organ donation and energy saving. In education, teachers draw on commitment and modeling to build study habits. In clinical settings, motivational interviewing deliberately avoids pressure and instead helps people voice their own reasons for change, reflecting research showing that people resist being told what to do. In politics, framing and identity appeals shape how policies are received, a topic explored in political psychology.

Limitations and Open Questions

Influence research has real strengths, including many field experiments, but it also has limits. Some popular findings rest on small samples, and the wider replication crisis in psychology has prompted re-examination of effects such as behavioral priming and ego depletion. Effects that are statistically reliable are often small for any individual, so claims that a single trick can "control" people overstate the evidence. Much of the classic work was conducted with Western university students, and cultural research suggests that conformity, for instance, varies between more individualistic and more collectivist societies. Current research is focused on online persuasion, misinformation resistance and the ethics of personalized targeting.

Further Reading

For a deeper look at the topics on this page, start with Cialdini's Influence for the principles of compliance, Kahneman's Thinking, Fast and Slow for the cognitive shortcuts that persuasion relies on, and Thaler and Sunstein's Nudge for choice architecture. On this site, the companion page on persuasion and compliance techniques covers sequential request strategies in more detail, and our overview of social influence places these ideas within wider social psychology.