12 Psychological Tricks That Actually Work

The psychological tricks that work most reliably come from peer-reviewed journals, not self-help threads. The best-supported ones are reciprocity, social proof, anchoring and the foot-in-the-door technique, which in Freedman and Fraser's 1966 study raised agreement to a big request from 17% to 76%. The most useful ones work on yourself: planning your next step as an "if X, then I'll do Y" rule improved follow-through across 94 studies (Gollwitzer & Sheeran, 2006).

Each trick below names the study behind it, none of them requires deception, and the section on what doesn't replicate is upfront about the famous effects that failed when scientists tested them again.

You'll see these called "psychology tricks," "psychological tricks," or "psychology hacks" depending on where you read about them. They all refer to the same documented cognitive and social effects covered below.

The 12 psychological tricks at a glance

#	Technique	Core Mechanism	Best Used For
1	Benjamin Franklin Effect	Cognitive consistency	Building new relationships
2	Foot-in-the-Door	Self-perception theory	Getting large commitments
3	Door-in-the-Face	Reciprocal concession	Negotiation
4	Mirroring	Behavioral synchrony	Rapport and trust-building
5	Pratfall Effect	Approachability signal	Public speaking, first impressions
6	Mere Exposure Effect	Familiarity heuristic	Presence and brand-building
7	Scarcity Principle	Loss aversion	Creating urgency
8	Reciprocity Principle	Social obligation	Relationship investment
9	Anchoring Effect	Cognitive reference points	Price and salary negotiation
10	Social Proof	Conformity heuristic	Marketing, pitches, writing
11	Zeigarnik Effect	Open cognitive loops	Storytelling and retention
12	Labeling Technique	Identity formation	Leadership and coaching

Below, each one comes with the research behind it and how to spot it being used on you. First, though, the tricks most worth learning are the ones you can use on yourself.

Start here: four psychological tricks to use on yourself

These work on your own habits and decisions, need no one else's cooperation, and have some of the strongest evidence of anything in this article.

If-then planning (implementation intentions). Instead of "I'll exercise more," decide "If it's 7 a.m. on a weekday, then I put on my running shoes." A meta-analysis of 94 independent tests found these if-then plans had a medium-to-large effect on actually reaching goals (Gollwitzer & Sheeran, 2006). The plan hands the decision to the situation, so you don't have to decide again when motivation is low.

Talk to yourself by name. When you're anxious before a hard conversation or a presentation, coach yourself in the third person: "Okay, Sam, here's what you're going to do." Ethan Kross and colleagues (2014) found this kind of distanced self-talk reduced anxiety and improved performance compared with using "I." It gives you the perspective you'd naturally have when advising a friend.

Temptation bundling. Pair something you should do with something you want to do, and only allow the treat during the chore: the gripping audiobook only at the gym. In Katherine Milkman's 2014 study, participants who could only hear audiobooks while working out went to the gym significantly more often than a control group.

Use fresh starts. People are more likely to start new goals after "temporal landmarks" such as a new week, month, birthday or semester (Dai, Milkman & Riis, 2014). If you've been meaning to start something, attach it to the next landmark on purpose instead of "someday."

The twelve below are social: they describe how people influence each other.

Why "psychological tricks" have a bad reputation

Most "psychology hacks" online are pseudoscience in scientific language. They misrepresent studies, confuse correlation with causation, and promise social superpowers that don't exist.

The effects below come from peer-reviewed research, and most have been replicated many times. A few rest on small original studies, which is noted where it matters. Some are subtle and some are surprising, and you've probably been on the receiving end of most of them without noticing.

1. The Benjamin Franklin Effect

Ask someone for a small favor before you need a big one, and they'll like you more afterward.

In the 1700s, Benjamin Franklin had a political rival who refused to cooperate with him. Instead of trying to charm the man, Franklin asked to borrow a rare book from his library. The rival lent it, and afterward his hostility toward Franklin visibly softened. Franklin used the technique throughout his political career.

In 1969, psychologists Jecker and Landy ran the first modern study of the effect. Participants asked to return money to the experimenter, framed as a personal favor, liked the experimenter significantly more than participants who weren't asked. Helping created cognitive consistency: I did this person a favor, so I must like them.

It works because your brain needs your actions and beliefs to match. When you do something kind for someone, your mind decides after the fact that you must like them, or why would you have helped?

To use it, ask for a small, easy favor early in a new professional or personal relationship: "Could you recommend a good coffee place nearby?" or "Would you mind looking at this paragraph?" Helping you creates real goodwill in the other person, not the resentment you might expect.

To spot it, notice that someone who asks for lots of small favors may be building unconscious affinity, not just being needy.

2. The foot-in-the-door technique

Start with a small request. Once someone has said yes to that, they're far more likely to agree to a much bigger one.

In 1966, Freedman and Fraser knocked on doors in Palo Alto and asked homeowners to display a small 3-inch sign supporting safe driving in their window. Most agreed, since it was tiny and reasonable. Two weeks later, a different researcher asked the same homeowners to put a large, ugly "Drive Carefully" billboard in their front yard. 76% of those who'd agreed to the small sign said yes. Among homeowners never asked about the small sign, only 17% agreed.

The first "yes" changed how people saw themselves. They now had a self-image as someone who cares about safe driving, and refusing the bigger request clashed with it.

Self-perception theory explains why: we infer our attitudes from our behavior. Once you've acted, you build an identity around the action, and turning down related requests later creates internal inconsistency.

To use it, ask for something small and easy before asking for something significant like a long meeting, a major favor, or a large purchase. The first yes makes the second more likely.

To spot it, look at online petitions, free trial sign-ups, and newsletter opt-ins. They're engineered foot-in-the-door tactics meant to move you toward a bigger conversion.

3. The door-in-the-face technique

Open with an outrageously large request you know will be refused, then follow with the reasonable request you actually wanted. Acceptance of the second request jumps.

Cialdini et al. (1975) asked strangers to volunteer as counselors for juvenile delinquents for two years, a huge commitment, and everyone said no. The researchers then scaled back: "Okay, would you take them on a two-hour zoo trip?" About half of the people who'd heard the large request first agreed, roughly three times the rate of people asked only about the zoo trip (about 17%).

The mechanism is reciprocal concession. When you lower your demand, the other person feels they've won a negotiation, and reciprocity norms push them to give something back, which here means agreeing to your real request.

To use it in negotiations, salary discussions, or anywhere you want a specific outcome, anchor with a larger ask first. The contrast makes your real request look much more reasonable.

To spot it, watch car dealers, real estate agents, and recruiters. An absurdly high opening offer is often deliberate, an anchor meant to make the real number feel like a win.

4. Mirroring (behavioral synchrony)

Subtly reflect the other person's body language, speaking pace, and word choices, and they'll find the conversation more pleasant and trust you more without knowing why.

Tanya Chartrand and John Bargh's 1999 "Chameleon Effect" study found that people naturally mimic the postures and mannerisms of whoever they're talking to, and that this mimicry increases liking. When a confederate deliberately mirrored participants' body language, participants rated the interaction as smoother and the confederate as more likeable. They had no idea they were being mirrored.

Later studies found similar effects in practical settings: in a Dutch restaurant study, waitresses who repeated customers' orders back word for word received larger tips than those who paraphrased (van Baaren et al., 2003).

Behavioral synchrony signals affiliation. When we move in sync with someone, our brains read it as shared intent and belonging, an ancient safety signal that slips past conscious scrutiny.

To use it, match the other person's energy and speaking pace. If they speak slowly and deliberately, slow down. If they use a particular phrase, echo it back naturally. Reflect rather than parrot.

To spot it, remember that trained salespeople and negotiators do this on purpose. If a conversation feels unusually warm and you can't say why, check whether the other person is physically mirroring you.

5. The pratfall effect

A visible human flaw or small mistake makes competent people more likable.

In Elliot Aronson's 1966 study, participants listened to recordings of students answering quiz questions. One student got nearly everything right and came across as highly competent; another was average. In one version, the competent student spilled coffee on himself during the recording. Participants rated the competent student who spilled coffee as significantly more likable than the same student without the accident. The average student who spilled coffee was rated less likeable.

The pratfall only helps people already seen as competent. For them, a small flaw signals approachability. For an average performer, the same flaw adds to the impression of inadequacy.

High competence with no visible weakness creates subtle suspicion and distance. A minor imperfection shows real humanity and makes the competent person seem like someone you could actually talk to.

To use it, don't try to look flawless in presentations, writing, or conversations. Acknowledge uncertainty, mention a past mistake honestly, or open with a self-deprecating remark before you show your mastery. The vulnerability lowers people's defenses.

To spot it, notice polished communicators who admit one specific, contained imperfection. They're often doing it deliberately.

6. The mere exposure effect

The more familiar something is, the more you like it, even if you can't say why.

In a 1968 series of experiments, Robert Zajonc showed participants Chinese characters, geometric shapes, and photos of strangers, some often, some rarely, some not at all. Participants consistently rated the most frequently seen items as more pleasant, more attractive, and (for faces) more trustworthy, without being told they'd seen them before.

The effect has been replicated with music, brand logos, faces, and product packaging, and it works even below conscious awareness.

Familiarity makes things easier to process, and your brain reads that ease as a sign of safety and value. Something familiar doesn't register as a threat.

To use it at work, show up consistently before you need anything. Attend the meetings, comment thoughtfully, and stay visible. The exposure turns into goodwill long before you make a specific request.

To spot it, look at advertising frequency, logo saturation, and political repetition. They're pure exposure effect: instead of persuading people, they make a name and image unavoidable.

7. The scarcity principle

When something seems rare, limited, or about to run out, people want it more, whatever its actual quality or value.

Worchel, Lee, and Adewole (1975) gave participants identical cookies from two jars, one nearly full and one with only two cookies. Participants consistently rated cookies from the nearly empty jar as tastier, more valuable, and worth paying more for.

Cialdini documented the same pattern in sales and fundraising in Influence (1984): limited supply and deadlines make people want things more, even when nothing about the thing has changed.

The mechanism is loss aversion, the same force that makes losing $100 feel twice as bad as gaining $100 feels good. Possible scarcity triggers fear of loss, which overrides rational cost-benefit analysis. Loss aversion is also one of the ways your brain damages your finances; the scarcity principle uses the same mechanism against you.

To use it, be honest about real constraints when you present ideas, opportunities, or offers. "We can only take three clients this quarter" or "This window closes at the end of the month" isn't manipulative if it's true, and it works because it activates the same loss-aversion circuitry.

To spot it, look for "Only 3 left in stock," countdown timers, and "Offer expires tonight." These are scarcity triggers, real or manufactured, so ask yourself whether the scarcity is real.

8. The reciprocity principle

Give something first, with no conditions, and most people will feel a strong, almost involuntary obligation to return the favor.

In a study by Regan (1971), a confederate gave participants an unsolicited Coca-Cola during an experiment break. Those participants later bought twice as many raffle tickets from the confederate as participants who got nothing. The returned "favor" was worth far more than the original gift.

A restaurant study by David Strohmetz and colleagues (2002) found that servers who left a single mint with the bill increased tips by 3%. Two mints increased them by 14%. Two mints, with the server coming back to leave the second and saying "You were such great customers, here's another," increased tips by 23%. The gesture drove the effect, not the mint.

Reciprocity runs deep in human social life. In small hunter-gatherer groups, failing to return favors meant social exclusion and often death. The obligation to repay is strong enough to work even when the gift was unsolicited.

To use it, give value before you ask for anything. Send someone an article they'd find useful, introduce two people who should know each other, or offer your expertise on a problem before proposing a paid engagement. A spontaneous gift creates real social debt.

To spot it, recognize free samples, unsolicited gifts from charities, and early generosity from salespeople as calculated first gifts meant to trigger reciprocity.

9. The anchoring effect

The first number or piece of information in a negotiation or decision frames everything after it, often irrationally.

In Tversky and Kahneman's classic 1974 studies, participants spun a wheel rigged to land on 10 or 65 before estimating the percentage of African nations in the UN. The median estimate was 25% among those who saw 10, and 45% among those who saw 65. The random number had no logical connection to the question, yet it changed the answers.

In salary negotiation research, people who received a higher first offer consistently settled at a higher final salary than those who received a lower one, even when both sides knew the opening number was only a starting point.

The brain uses the first available reference point as a shortcut and calculates every later estimate relative to that anchor instead of from a rational zero.

To use it in negotiations, set the anchor before the other party does. Whoever names the first number controls the center of gravity for the whole discussion.

To spot it, treat any opening offer on price, salary, timeline, or scope as a likely anchor, and recognize it before it reshapes your sense of what's reasonable. For a deeper look at how anchoring is used against you commercially, see how con artists and salespeople exploit the anchoring effect.

10. Social proof

People default to what the crowd does, especially when a situation is ambiguous, and that default gets exploited constantly.

In Solomon Asch's 1951 conformity experiments, about 75% of participants gave an obviously wrong answer about the length of a line at least once when the rest of the group gave it first. They didn't actually see the line differently. Group consensus overwhelmed their own perception.

In a hotel study by Noah Goldstein, Robert Cialdini and Vladas Griskevicius (2008), signs saying "The majority of guests reuse their towels" beat standard environmental messages by 26%. Simply stating what most people in the same room did outperformed every other persuasion framing.

When you're uncertain, other people's behavior is useful information about what's correct or safe. That heuristic works in most situations and fails badly in manufactured ones.

To use it in writing, speeches, and pitches, lead with what people like your audience have done: "9 out of 10 readers who started this newsletter said..." or "Most of our clients in your situation chose..." Specific, true social proof is both ethical and effective.

To spot it, look at star ratings, review counts, "bestseller" labels, and follower counts. They work, so the question is whether the consensus behind them is real.

11. The Zeigarnik effect (applied to conversation)

Unfinished stories stick in memory far better than finished ones, and people feel compelled to come back to incomplete loops.

As the story goes, Soviet psychologist Bluma Zeigarnik noticed that waiters remembered open orders but forgot them once they were paid. Her 1927 experiments found people recalled interrupted tasks better than finished ones. The memory part has proved shaky in later research (see what doesn't replicate), but the pull to go back and finish an interrupted task holds up well.

In persuasion, this means leaving a conversation or piece of content deliberately incomplete keeps the other person engaged and thinking about it long after it ends.

Your brain treats an open loop as an unfinished task and won't let it go until it's resolved. The same mechanism powers cliffhangers, "To be continued," and the itch to finish a half-done crossword.

To use it, don't reveal everything up front in presentations. In writing, pose a question you'll answer later. In conversation, leave a compelling partial thought before scheduling a follow-up: "I've been thinking about a much simpler way to solve this. Let's pick it up next week." The loop stays open until you close it together.

To spot it, notice Netflix season finales, podcast episodes that end with "we'll get to that next week," and email subject lines written as questions. They're all deliberate open loops. The Zeigarnik effect also explains why unfinished tasks feel so mentally heavy; here's a deeper look at how unfinished tasks hijack your brain and how to stop them.

12. The labeling technique

Tell someone they have a positive trait, even before they've fully shown it, and they'll tend to behave in ways that confirm the label.

In Miller, Brickman and Bolen's 1975 study, fifth graders were repeatedly told they were "neat and tidy." Two weeks later, those students cleaned their classroom much more carefully than a control group given standard instructions about cleanliness. Being told they were tidy people made them act tidier.

A separate study by Kraut (1973) found that people labeled "charitable" after an initial donation were significantly more likely to donate again two weeks later than people given no label. The label changed how they saw themselves.

People act in line with how they see themselves. Give someone an accurate or slightly aspirational positive label and they absorb it into their identity, and identity drives behavior.

To use it in leadership and collaboration, name what you observe: "You're the kind of person who actually follows through," or "You tend to see things others miss." Specific, truthful labels like these reinforce identity and shape future behavior.

To spot it, pay attention when someone describes you as a certain kind of person, especially early in a relationship, and ask whether the label serves your interests or theirs. Cults, abusive relationships, and high-pressure sales all use positive labels to produce compliance.

The common thread: cognitive consistency

Every trick on this list relies on one principle: people need their thoughts, feelings, and behaviors to be consistent with each other. When they aren't, we feel cognitive dissonance, an uncomfortable tension we resolve by bringing our beliefs into line with our actions.

The Benjamin Franklin Effect works because helping someone produces the belief I must like them. Labeling works because being told you're charitable produces the behavior I should act charitably. Anchoring works because the first number becomes the reference point for everything else.

Once you see the mechanism, you can see why these effects last. They exploit the brain's rational drive to stay internally coherent, more than any irrationality.

What doesn't replicate

Psychology went through a "replication crisis" in the 2010s, when large teams re-ran famous studies with bigger samples. Several effects that still circulate as psychology tricks didn't survive:

Power posing. The claim that standing like a superhero for two minutes raises testosterone and lowers cortisol (Carney, Cuddy & Yap, 2010) failed in a larger replication (Ranehill et al., 2015). People may feel a little more confident; the hormone story didn't hold.
Ego depletion. The idea that willpower is a fuel tank you drain by resisting temptation was tested across 23 labs in a registered replication; the effect was close to zero (Hagger et al., 2016).
The pen-in-mouth smile. Holding a pen in your teeth to force a smile and feel happier (Strack et al., 1988) didn't replicate across 17 labs (Wagenmakers et al., 2016). Later work suggests deliberately smiling may have a small effect, far smaller than the original.
Priming people to walk slowly. Reading words about old age didn't make people walk more slowly when the study was re-run with better controls (Doyen et al., 2012).
The Zeigarnik memory effect. A 2025 meta-analysis found no reliable memory advantage for unfinished tasks, though people do reliably tend to resume them (Ghibellini & Meier, 2025).

Of the twelve above, the pratfall effect and the labeling technique rest on smaller, older studies, so treat them as plausible rather than proven. Reciprocity, social proof, anchoring and foot-in-the-door have been replicated many times.

Think Like a Detective: Learning to spot these techniques in real time is a form of critical thinking applied to social situations. It connects directly to how we evaluate persuasion, argumentation, and rhetoric. If that interests you, cognitive biases are the next layer: the predictable errors in how your brain evaluates evidence, and surprisingly, high intelligence doesn't protect you from them.

Using these ethically

Knowing these techniques brings responsibility. The Benjamin Franklin Effect works whether you're building real rapport or manipulating someone, and reciprocity works whether you're giving real value or engineering obligation. What separates the two is your intent and the honesty of the exchange.

Use these techniques to communicate better, build trust faster, and understand the invisible forces in every social interaction. Don't use them to get around someone's decision-making or to manufacture consent they wouldn't give if they understood the situation.

The most durable persuasion is the kind the other person would endorse if they could see the whole picture. These techniques speed up that kind of trust, and they speed up its opposite just as well.

Frequently Asked Questions (FAQ)

Are these psychological tricks actually proven by science, or is this more pop psychology?

Every technique in this list comes from peer-reviewed research, but the strength of evidence varies. Foot-in-the-door, door-in-the-face, anchoring, reciprocity and social proof each have decades of supporting literature. The pratfall effect and labeling rest on smaller, older studies. Effect sizes vary by context; these are reliable tendencies, not laws of physics. Some famous "tricks" such as power posing didn't hold up at all, which is why they aren't on this list.

Is it ethical to use psychological influence techniques on people?

The ethics depend entirely on intent and transparency. Mirroring to build genuine rapport is different from mirroring to extract a confession. Reciprocity through real value-giving is different from engineering obligation through calculated gifts. Use these techniques in ways you'd be comfortable being transparent about.

Can I protect myself from these techniques being used on me?

Awareness does help. Research on anchoring shows that simply being warned that an anchor exists reduces its effect size. For each technique, name it when you notice it. Asking "Is this a foot-in-the-door situation?" pauses the automatic compliance response and returns decision-making to your conscious mind.

Which of these is most powerful for professional situations?

Reciprocity and social proof consistently produce the largest effect sizes in professional and commercial contexts. But the labeling technique is arguably the most underused: naming someone's positive traits in a specific, credible way reshapes how they behave in ways that compound over time.

What's the difference between persuasion and manipulation?

Persuasion works by changing what someone genuinely believes or wants. Manipulation works by bypassing their decision-making to produce behavior they wouldn't freely choose with full information. The techniques above can do either. The determining factor is whether you'd be comfortable with the other person seeing exactly what you're doing and why.

What psychological tricks can I use on myself?

The best-supported are if-then planning ("If it's 7 a.m., then I put on my running shoes"), talking to yourself in the third person before stressful moments, temptation bundling (pairing a chore with a treat you only allow during it), and starting goals at a fresh-start date like a Monday or the first of the month. Each has published experimental support, listed in the sources below.

Which famous psychology tricks don't actually work?

Power posing, ego depletion, the pen-in-mouth smile and slow-walking priming all failed in large replication studies. The memory part of the Zeigarnik effect is also unreliable. They're still widely shared online, often with the original study cited and the failed replication left out.

Is there a difference between "psychology tricks" and "psychological tricks"?

No. They're the same thing with different phrasing. Both terms refer to the documented behavioral and cognitive effects covered in this article: the Benjamin Franklin effect, foot-in-the-door, anchoring, reciprocity, social proof, and the rest.

Sources

Cialdini, R. B. (1984). Influence: The Psychology of Persuasion. Harper Business. Foundational taxonomy of compliance principles (reciprocity, scarcity, authority, social proof, liking, commitment).
Langer, E. J., Blank, A., & Chanowitz, B. (1978). The mindlessness of ostensibly thoughtful action: The role of "placebic" information in interpersonal interaction. Journal of Personality and Social Psychology, 36(6), 635–642. https://doi.org/10.1037/0022-3514.36.6.635. Copy-machine study: a reason, even a trivial one, dramatically increases compliance.
Freedman, J. L., & Fraser, S. C. (1966). Compliance without pressure: The foot-in-the-door technique. Journal of Personality and Social Psychology, 4(2), 195–202. https://doi.org/10.1037/h0023552. Small initial commitments predict larger subsequent compliance.
Tversky, A., & Kahneman, D. (1974). Judgment under uncertainty: Heuristics and biases. Science, 185(4157), 1124–1131. https://doi.org/10.1126/science.185.4157.1124. Anchoring effect: initial numbers persistently distort subsequent estimates.
Strack, F., Martin, L. L., & Stepper, S. (1988). Inhibiting and facilitating conditions of the human smile: A nonobtrusive test of the facial feedback hypothesis. Journal of Personality and Social Psychology, 54(5), 768–777. https://doi.org/10.1037/0022-3514.54.5.768. Original pen-in-mouth study; see Wagenmakers et al. (2016) for the failed replication.
Gollwitzer, P. M., & Sheeran, P. (2006). Implementation intentions and goal achievement: A meta-analysis of effects and processes. Advances in Experimental Social Psychology, 38, 69–119. If-then plans improved goal attainment across 94 independent tests.
Kross, E., et al. (2014). Self-talk as a regulatory mechanism: How you do it matters. Journal of Personality and Social Psychology, 106(2), 304–324. Distanced (third-person) self-talk reduced anxiety and improved performance.
Milkman, K. L., Minson, J. A., & Volpp, K. G. M. (2014). Holding the Hunger Games hostage at the gym: An evaluation of temptation bundling. Management Science, 60(2), 283–299. Temptation bundling increased gym attendance.
Dai, H., Milkman, K. L., & Riis, J. (2014). The fresh start effect: Temporal landmarks motivate aspirational behavior. Management Science, 60(10), 2563–2582. Goal pursuit rises after temporal landmarks.
Miller, R. L., Brickman, P., & Bolen, D. (1975). Attribution versus persuasion as a means for modifying behavior. Journal of Personality and Social Psychology, 31(3), 430–441. The "neat and tidy" labeling study.
Goldstein, N. J., Cialdini, R. B., & Griskevicius, V. (2008). A room with a viewpoint: Using social norms to motivate environmental conservation in hotels. Journal of Consumer Research, 35(3), 472–482. Hotel towel social-proof study.
Hagger, M. S., et al. (2016). A multilab preregistered replication of the ego-depletion effect. Perspectives on Psychological Science, 11(4), 546–573. Ego depletion effect near zero across 23 labs.
Wagenmakers, E.-J., et al. (2016). Registered replication report: Strack, Martin, & Stepper (1988). Perspectives on Psychological Science, 11(6), 917–928. Pen-in-mouth facial feedback effect not replicated.
Ranehill, E., et al. (2015). Assessing the robustness of power posing: No effect on hormones and risk tolerance in a large sample of men and women. Psychological Science, 26(5), 653–656.
Doyen, S., Klein, O., Pichon, C.-L., & Cleeremans, A. (2012). Behavioral priming: It's all in the mind, but whose mind? PLoS ONE, 7(1), e29081.
Ghibellini, R., & Meier, B. (2025). [Meta-analysis of interrupted-task recall and resumption]. Humanities and Social Sciences Communications, 12. https://doi.org/10.1057/s41599-025-05000-w. Meta-analysis: no reliable memory advantage for unfinished tasks; a general tendency to resume them.
van Baaren, R. B., Holland, R. W., Steenaert, B., & van Knippenberg, A. (2003). Mimicry for money: Behavioral consequences of imitation. Journal of Experimental Social Psychology, 39(4), 393–398. Verbatim mimicry increased restaurant tips.

12 Psychological Tricks That Actually Work (And the Science Behind Each One)