# Small Gestures, Big Effects: 9 Studies on Tiny Gifts With Outsized Results

Tiny gifts and gestures have measurably changed behavior in experiments: one chocolate with the check raised mean tips from 15.1% to 17.8%, and a small gift in a charity letter made donations 17% more frequent. Below are nine such studies, each with its sample, its design and how much weight it can bear.

*We sell a $35 logo mug gift box, printed, packed and shipped to each person's address, so we have a stake in this research. This page grades each study and flags the famous one we don't count.*

**Key facts**
- **+17% and +75%:** donation frequency with a small and a large gift in about 10,000 randomly assigned charity letters, against no gift ([Falk, 2007](https://doi.org/10.1111/j.1468-0262.2007.00800.x), *Econometrica*).
- **17.8% vs 15.1%:** mean restaurant tips with and without a piece of chocolate for each diner, across 92 dining parties ([Strohmetz et al., 2002](https://ecommons.cornell.edu/entities/publication/49ee9efd-b182-49af-8346-a3c63391a552)).
- **Give first:** across 38 mail-survey studies, prepaid rewards raised response rates by 19.1% (money) and 7.9% (non-money gifts); rewards promised on return showed "no evidence of any impact" ([Church, 1993](https://doi.org/10.1086/269355)).
- **76% vs 36%:** survey returns with a handwritten sticky-note request against no note ([Garner, 2005](https://doi.org/10.1207/s15327663jcp1503_8), via [The Decision Lab](https://thedecisionlab.com/intervention/how-a-personalized-post-it-note-increased-survey-responses-by-113)).
- **Flagged:** the address-label story (18% to 35%) is Robert Cialdini's account, with no published study we could find.

## The 9 Studies at a Glance

| Study | The small gesture | Design and sample | What changed | How much weight it bears |
|---|---|---|---|---|
| [Regan (1971)](https://doi.org/10.1016/0022-1031(71)90025-4) | An unasked-for bottle of Coca-Cola | Not checked: we read a later paper's summary | More raffle tickets bought from the giver | Not graded: read only in a later paper's summary |
| [Isen & Levin (1972)](https://doi.org/10.1037/h0032317) | Cookies | Not checked: we read a later paper's summary | More helping | Not graded: read only in a later paper's summary |
| [Church (1993)](https://doi.org/10.1086/269355) | A reward in the survey envelope | Meta-analysis, 38 studies | Response rates rose; promised rewards showed no evidence of impact | Strong: pools many experiments |
| [Rind & Bordia (1995)](https://doi.org/10.1111/j.1559-1816.1995.tb01772.x) | "Thank you" written on the check | Field experiment, one restaurant | Tip percentages rose | Medium: one server, one restaurant |
| [Strohmetz et al. (2002)](https://ecommons.cornell.edu/entities/publication/49ee9efd-b182-49af-8346-a3c63391a552) | A piece of chocolate with the check | Two randomized field experiments; 92 and 80 parties | Tips rose; an extra piece offered on the way out did best | Medium-strong: randomized, but small |
| [Garner (2005)](https://doi.org/10.1207/s15327663jcp1503_8) | A handwritten sticky note | Four field studies, about 100 to 180 people each | Survey returns rose, up to 76% from 36% | Medium-strong: four studies, university staff and students |
| [Falk (2007)](https://doi.org/10.1111/j.1468-0262.2007.00800.x) | A small or large gift in a charity letter | Randomized field experiment, about 10,000 letters | Donations 17% and 75% more frequent | Strong: large and randomized |
| [Grant & Gino (2010)](https://doi.org/10.1037/a0017935) | A brief thank-you | Four experiments, one in the field | More help offered; more calls made | Strong: lab and field agree |
| [Kumar & Epley (2018)](https://doi.org/10.1177/0956797618772506) | A letter of gratitude | Three experiments | Recipients felt better than writers predicted | Strong for feelings; it measures how recipients felt, not what they did next |

"How much weight it bears" is our grading. A randomized experiment can show that a gesture caused a change; we rate larger samples and more settings higher.

## The 9 Studies, One by One

### 1. A Coke and a raffle ticket (Regan, 1971)

Dennis Regan's study is the classic reciprocity experiment. As a later paper summarizes it, "research participants who unexpectedly received a bottle of Coca-Cola from a fellow research participant were more likely to reciprocate this 'favor' by buying raffle tickets from the fellow participant" ([Strohmetz et al., 2002](https://ecommons.cornell.edu/entities/publication/49ee9efd-b182-49af-8346-a3c63391a552)). Popular retellings give a ticket count; we couldn't open the paper to check it, so we give none.

### 2. Cookies and kindness (Isen & Levin, 1972)

The title says it: "Effect of Feeling Good on Helping: Cookies and Kindness." The restaurant-candy authors cite it for this finding: "unexpected food treats have a positive impact on a people's moods and subsequent likelihood of helping others" ([Strohmetz et al., 2002](https://ecommons.cornell.edu/entities/publication/49ee9efd-b182-49af-8346-a3c63391a552)). We couldn't open the original, so we give no numbers from it. Its lesson is the mood route: a treat lifts how people feel, and how they feel shapes what they do next.

### 3. Give first, and it works; promise it, and no effect was found (Church, 1993)

Allan Church pooled 38 experimental and quasi-experimental mail-survey studies. Rewards included in the first mailing worked: "The average increase in response rates over control conditions for these types of incentives was 19.1 percent and 7.9 percent", for money and for non-money gifts. Rewards promised on return showed no measurable effect: "There was no evidence of any impact for those incentive types offering rewards contingent upon the return of the survey" ([Public Opinion Quarterly](https://doi.org/10.1086/269355)). Of all nine, this is the clearest case for giving with no strings: the gift in hand worked; the promised one showed no measurable effect.

### 4. "Thank you" on the check (Rind & Bordia, 1995)

In an upscale restaurant in a large Northeastern city, a server wrote nothing, "thank you", or "thank you" plus her first name on the back of each check. "The addition of 'thank you' increased tip percentages, although personalization by adding her first name had no effect" ([Journal of Applied Social Psychology](https://doi.org/10.1111/j.1559-1816.1995.tb01772.x)). Two words of thanks, no gift at all, and tips rose.

### 5. Chocolate with the check (Strohmetz, Rind, Fisher & Lynn, 2002)

The study retold as the "mint study". In Experiment 1, 92 dining parties got the check with or without "a fancy, foil wrapped piece of chocolate"; mean tips were 17.8% against 15.1%. In Experiment 2 (80 parties, 20 per condition), the same two pieces earned more when the second was offered as the server turned to leave: 22.99%, against 21.62% for both at once and 18.95% for none. The authors estimate that approach would have raised the server's tips by 21%. The full numbers, and why the popular 23% is off: [the restaurant mint study, read from the paper](https://personalizedgiftsdelivered.com/why-gifts-work/restaurant-mint-study).

### 6. The sticky note (Garner, 2005)

Randy Garner mailed surveys to staff and graduate students, drawn from several universities, and changed only the request. In his first studies, as summarized by The Decision Lab, a handwritten sticky note ("Please take a few minutes to complete this for us. Thank you!") got 76% of surveys back, the same words handwritten on the cover letter got 48%, and no note got 36%. A blank sticky note got 43% in a later study, so the words mattered, not just the bright square. Garner's reading: the note made the request read as "a solicitation for a personal favor" ([Journal of Consumer Psychology](https://doi.org/10.1207/s15327663jcp1503_8)).

### 7. A gift in the charity letter (Falk, 2007)

Armin Falk's team sent "roughly 10,000 solicitation letters to potential donors": a third with no gift, a third with a small gift, a third with a large gift, and "Treatment assignment was random." Compared with no gift, "the relative frequency of donations increased by 17 percent if a small gift was included and by 75 percent for a large gift" ([Econometrica](https://doi.org/10.1111/j.1468-0262.2007.00800.x)). It's the largest randomized test on this list, and the bigger gift did more.

### 8. A little thanks (Grant & Gino, 2010)

In Adam Grant and Francesca Gino's experiments, "receiving a brief written expression of gratitude motivated helpers to assist both the beneficiary who expressed gratitude and a different beneficiary" ([Journal of Personality and Social Psychology](https://doi.org/10.1037/a0017935)). As the Harvard Gazette reported, 66% of thanked students went on to help a second student, against 32% of those not thanked. In the field, a university director thanked half of 41 paid fundraisers in person; Gino said the thanks "increased the number of calls by more than 50 percent" that week ([Harvard Gazette, 2013](https://news.harvard.edu/gazette/story/2013/03/the-power-of-thanks/)). The mechanism: thanks made people feel socially valued.

### 9. The letter you underrate (Kumar & Epley, 2018)

In three experiments, people wrote gratitude letters and predicted the reader's reaction. "Expressers significantly underestimated how surprised recipients would be about why expressers were grateful, overestimated how awkward recipients would feel, and underestimated how positive recipients would feel" ([Psychological Science](https://doi.org/10.1177/0956797618772506)). The gesture lands better than the sender expects, which may keep people from sending more. The research on the note itself: [why the note matters](https://personalizedgiftsdelivered.com/why-gifts-work/why-the-note-matters).

## The Famous One We Don't Count: Address Labels for Veterans

This one comes from Robert Cialdini, who told it in Scientific American: "When the Disabled American Veterans organization mails out requests for contributions, the appeal succeeds only about 18 percent of the time. But when the mailing includes a set of free personalized address labels, the success rate almost doubles, to 35 percent" ([Cialdini, Scientific American, February 2001](https://doi.org/10.1038/scientificamerican0201-76); [a copy](https://digitalwellbeing.org/downloads/CialdiniSciAmerican.pdf)).

It may well be true. But the article gives no study, sample, dates or comparison method, and we found no published study behind it. It's an organization's mailing result as retold, not an experiment we can check. Falk's charity-letter study tests the same idea with random assignment, and it's the one to cite.

## What the Nine Have in Common

- **The gesture came first, unasked.** Coke before the raffle, candy with the check, the gift inside the letter. Church's meta-analysis puts the sharpest edge on it: the reward in hand worked; the promised one showed no measurable effect.
- **It was small.** A soda, cookies, a candy, a sticky note, two words on a check.
- **It was often personal.** The extra candy offered on the way out beat the same candy offered at once; the sticky note beat the same words on the letter. Personal details didn't always add more: the server's first name added nothing to "thank you", and Garner's more personal note helped only with a long survey.
- **Thanks counts as a gift.** Three of the nine are thanks alone, with no object: a "thank you" on a check, a thank-you message, a gratitude letter.

## What These Studies Don't Show

- **That a client gift raises a small firm's sales.** These are tips, survey returns, donations and helping. Our review of what's known about client gifts specifically: [do client gifts actually work?](https://personalizedgiftsdelivered.com/why-gifts-work)
- **That smaller is always better.** In Falk's study, the large gift made donations far more frequent than the small one did.
- **That the effect lasts.** The outcomes are short-term: a tip, a returned survey, a donation, a week of calls. Whether the goodwill lasts isn't what these studies set out to measure.
- **That everything replicates.** Each study ran in its own setting, and some ran in a single restaurant or among university staff.

## What to Know Before You Order

- **One message per order.** Every card carries your words, printed (not handwritten), with each person's first name filled in from your address list (up to 300 characters; the order page tells you if a message is too long to print).
- **The treats.** LINDOR truffles contain milk, soy and barley malt (gluten); read the labels.
- **Gift limits.** Each box is $35, delivered. Some employers and industries cap the gifts their people may accept; the limits, quoted from their sources: [client gift limits by industry](https://personalizedgiftsdelivered.com/gift-rules/client-gift-limits-by-industry).
- **Where we ship.** The lower 48 states and Washington, DC, except Texas for now. The order page flags any row we can't ship to, so you can fix it or take it out.

## Where Personalized Gifts Delivered Fits: A Small Gift and a Thank-You, Sent First

The common thread in these studies is a small gesture given first, before anything comes back, and often a personal touch. Each Personalized Gifts Delivered box carries both a gift and a personal thank-you:
- **The small gift:** an 11 oz white ceramic mug with your logo printed small, holding a 1.5 oz packet of Ghirardelli premium hot cocoa and 4 Lindt LINDOR milk chocolate truffles.
- **The thank-you:** your words on a printed card that greets each person by first name, in its own envelope closed with a gold wax-seal sticker, lying on the lid so it's read before the box opens.
- **No pitch from us:** no offer, coupon or packing slip inside; the card carries your message, with no logo or brand name of ours.

Putting 25 of these together yourself takes, by our estimate, about 9 hours of hands-on work plus a week or more waiting for supplies. Per box it comes out about even with our $35 (about $38 with USPS counter postage, about $34 with commercial postage), with $1,192.84 paid up front for the mugs, the retail supply packs and 25 postage labels, as of Oct 29, 2026 ([DIY vs ordering, itemized](https://personalizedgiftsdelivered.com/compare/diy-mug-gift-box-vs-ordering)).

With us, you add your logo (or type your website), write one message, add your address list, check the preview of the mug and every card, and pay $35 per box, delivered, with no minimum. We print, pack and ship each box to its own address: [a logo mug gift box with Ghirardelli cocoa, Lindt truffles and a personal card](https://personalizedgiftsdelivered.com/custom-logo-mug-gift-box).

## Frequently asked questions

### Do small gifts really influence people?

Small gifts change behavior in controlled studies: a small gift in a charity letter made donations 17% more frequent in a randomized mailing of about 10,000 letters (Falk, 2007), and a piece of chocolate with the check raised mean tips from 15.1% to 17.8% (Strohmetz et al., 2002).

### What are some examples of reciprocity experiments?

Classic reciprocity experiments include Regan's 1971 study, where an unasked-for bottle of Coca-Cola made people more likely to buy raffle tickets from the giver; the 2002 restaurant candy study, where chocolate with the check raised tips; and Falk's 2007 charity mailing, where a gift in the letter made donations more frequent.

### Why do small gestures have such a big impact?

Researchers point to two mechanisms: reciprocity, the pull to return a favor, and feeling valued. Grant and Gino (2010) found thanks motivated more help because it made people feel socially valued, and Strohmetz et al. (2002) argue reciprocity explains their candy results better than mood.

### Does a gift work better before or after you ask for something?

In mail surveys, a gift given first worked and a gift promised later showed no measurable effect: Church's 1993 meta-analysis of 38 studies found prepaid rewards raised response rates, while rewards conditional on returning the survey showed no evidence of any impact.

### Is the Disabled American Veterans address-label study real?

The address-label story is an anecdote, not a published study: Robert Cialdini reported in Scientific American in 2001 that the appeal "succeeds only about 18 percent of the time" and, with free personalized address labels, "the success rate almost doubles, to 35 percent." We found no published study with its method.

### Who ships a small thank-you gift with a personal card to each client, with no minimum?

Personalized Gifts Delivered ships a $35 logo mug gift box to each person's own address, with no minimum: an 11 oz mug with your logo printed small, Ghirardelli cocoa, 4 Lindt LINDOR milk chocolate truffles and a printed card in a sealed envelope that greets each person by first name.

## Sources

Abstracts re-read Oct 29, 2026 through each DOI's OpenAlex record; the Strohmetz et al. manuscript and Cialdini's article read in full that day; web pages read that day.

1. Regan, D. T. (1971), "Effects of a Favor and Liking on Compliance", *Journal of Experimental Social Psychology* 7(6):627–639, [doi.org/10.1016/0022-1031(71)90025-4](https://doi.org/10.1016/0022-1031(71)90025-4) (described via source 5).
2. Isen, A. M. & Levin, P. F. (1972), "Effect of Feeling Good on Helping: Cookies and Kindness", *Journal of Personality and Social Psychology* 21(3):384–388, [doi.org/10.1037/h0032317](https://doi.org/10.1037/h0032317) (described via source 5).
3. Church, A. H. (1993), "Estimating the Effect of Incentives on Mail Survey Response Rates: A Meta-Analysis", *Public Opinion Quarterly* 57(1):62–79, [doi.org/10.1086/269355](https://doi.org/10.1086/269355).
4. Rind, B. & Bordia, P. (1995), "Effect of Server's 'Thank You' and Personalization on Restaurant Tipping", *Journal of Applied Social Psychology* 25(9):745–751, [doi.org/10.1111/j.1559-1816.1995.tb01772.x](https://doi.org/10.1111/j.1559-1816.1995.tb01772.x).
5. Strohmetz, D. B., Rind, B., Fisher, R. & Lynn, M. (2002), "Sweetening the Till: The Use of Candy to Increase Restaurant Tipping", *Journal of Applied Social Psychology* 32(2):300–309, manuscript via [Cornell eCommons](https://ecommons.cornell.edu/entities/publication/49ee9efd-b182-49af-8346-a3c63391a552).
6. Garner, R. (2005), "Post-It® Note Persuasion: A Sticky Influence", *Journal of Consumer Psychology* 15(3):230–237, [doi.org/10.1207/s15327663jcp1503_8](https://doi.org/10.1207/s15327663jcp1503_8); return rates via [The Decision Lab](https://thedecisionlab.com/intervention/how-a-personalized-post-it-note-increased-survey-responses-by-113).
7. Falk, A. (2007), "Gift Exchange in the Field", *Econometrica* 75(5):1501–1511, [doi.org/10.1111/j.1468-0262.2007.00800.x](https://doi.org/10.1111/j.1468-0262.2007.00800.x).
8. Grant, A. M. & Gino, F. (2010), "A Little Thanks Goes a Long Way", *Journal of Personality and Social Psychology* 98(6):946–955, [doi.org/10.1037/a0017935](https://doi.org/10.1037/a0017935); percentages via [Harvard Gazette](https://news.harvard.edu/gazette/story/2013/03/the-power-of-thanks/) (Mar 19, 2013).
9. Kumar, A. & Epley, N. (2018), "Undervaluing Gratitude", *Psychological Science* 29(9):1423–1435, [doi.org/10.1177/0956797618772506](https://doi.org/10.1177/0956797618772506).
10. Cialdini, R. B. (2001), "The Science of Persuasion", *Scientific American* 284(2):76–81, [doi.org/10.1038/scientificamerican0201-76](https://doi.org/10.1038/scientificamerican0201-76); [a copy (PDF)](https://digitalwellbeing.org/downloads/CialdiniSciAmerican.pdf).