Intentions-Based Reciprocity to Monetary and Non-Monetary Gifts

Abstract

Social preference models emphasize that perceived intentions motivate reciprocity. However, laboratory tests of this theory typically manipulate perceived intentions through changes in wealth resulting from a sacrifice in pay by another. There is little evidence on whether reciprocity occurs in response to perceived intentions alone, independent of concurrent changes in pay and giver sacrifice (and any associated guilt from that sacrifice). This paper addresses this gap in the literature by implementing a modified dictator game where gifts to dictators are possible, but where gift transactions are also stochastically prevented by nature. This leads to instances of observed gift-giving intentions that yield no sacrifice or change in outcomes. In addition, this study uses both monetary and non-monetary gifts; previous studies typically use only monetary incentives, even though real-world applications of this literature often involve non-monetary incentives such as business or marketing gifts. The results show that on average, dictators reciprocated strongly to just the intention to give a gift, and they also reciprocated similarly to both monetary and non-monetary gifts. These results are consistent with intentions-based models of social preferences and with much of the marketing literature on business gifts.

1. Introduction

Social preference models propose that perceived intentions are a key driver of reciprocity [1,2]. However, economics experiments have typically tested this by varying whether a change in outcome is attributed to another individual or to chance [3,4,5]. In addition, in these games and in the related gift-exchange game [6,7,8], the initial giver must sacrifice from their own resources in order to show kindness and induce reciprocation. However, this sacrifice and change in outcome could induce guilt and lead to reciprocity via guilt-driven channels [9,10,11] instead of via solely an intentions mechanism. To better distinguish between these alternatives, this study tests for the effects of intentions in the absence of concurrent sacrifice and changes in outcomes.

In addition, existing studies have generally used monetary incentives [3,4,5,12], even though many real-world applications of reciprocity theory involve non-monetary incentives such as business or marketing gifts. The only gift exchange experiment to include non-monetary gifts found that individuals may perceive and respond to a non-monetary gift differently than an increase in wages [13]. More evidence is therefore needed to better understand whether results from experiments that use monetary incentives can extend to non-monetary applications, such as when firms or charities give gifts in hopes of encouraging reciprocal sales or donations.

This study addresses these gaps in the literature by implementing a modified dictator game. Non-dictator subjects will be allowed to give either monetary or non-monetary gifts to their dictator partner. However, nature will stochastically prevent these gift transactions from being completed after the gift offer is announced (this will be referred to as an overturned gift for simplicity). If an overturned gift generates similar reciprocity as an actual gift transfer (after controlling for wealth distribution preferences), this would imply that perceived intentions can induce reciprocity independent of changes in outcome, giver sacrifice, and any guilt associated with that sacrifice.

One could argue that gifts given in this context might not be perceived as kind, since the gift-giver has an ulterior motive [14,15,16]. Nevertheless, the ulterior motive is constant throughout the experiment and thus should not confound comparisons of reciprocity between successful gifts and overturned gifts. This study therefore tests whether intentions to give a gift can lead to positive reciprocity even when ulterior motives for the gift are present. This is not unlike reciprocity in many real-world applications, such as business gifts from salespeople, where the ulterior motive is clear and yet consumers still reciprocate positively (and even report increased liking of the giver [17]). Moreover, a lab experiment demonstrated that gift recipients may fail to properly draw inferences about the mental state (i.e., the motives) of a gift-giver [18]. Therefore, there is evidence that the presence of an ulterior motive does not necessarily preclude individuals from inferring positive intentions from a gift.1

By using both monetary and non-monetary gifts, this study can build a closer tie between the experimental game theory literature and field experiments in economics and marketing. Field studies have shown that non-monetary gifts can increase firm sales [17,19] and donations to charity [20], but these studies did not implement treatments that identify the exact mechanism behind the observed reciprocity. Although this study lacks the natural context of these field experiments, it is better able to isolate these different mechanisms via direct treatment manipulations, while the use of non-monetary gifts and the presence of an ulterior motive still brings the experiment a step closer to these real-world applications.

This study is loosely related to recent publications on reciprocity in bribery contexts. Pan and Xiao [21] use a three-person bribery paradigm and find that a monetary gift can lead to greater reciprocity than just the intention to give the same gift. However, their bribery game (like some other bribery-inspired games, e.g., Malmendier and Schmidt [22]) only tests for a different form of reciprocity where reciprocation reduces welfare for a third party and not the reciprocator. This is different from my experiment and some of the real-world scenarios it is motivated by, such as marketing gifts to a prospective customer or donor. In addition, intentions in their bribery game still result in sacrifices in pay by the giver even when the bribe is not given. Furthermore, other changes in outcomes often occur at the same time (e.g., a third player successfully giving a gift to the same receiver), leading to competing motives. Thus, the contexts and hypotheses tested in this bribery literature are different from the ones in this study.

This paper is more closely related to experiments that introduce noise into trust games in order to reduce a subject’s ability to infer intent from an observed outcome [23,24]. However, these studies do not measure reciprocity to an unambiguous and certain signal of intentions that is unaccompanied by giver sacrifice. Instead, they manipulate perceived intentions by introducing uncertainty and beliefs into the calculations. The only instance where intentions could be signaled clearly required a sacrifice in pay by the giver [24]. The results from this literature therefore imply that perceived intentions likely matter for reciprocity, but only in a context where uncertainty, beliefs, and/or giver sacrifice must also be accounted for (and only for monetary gifts). My experiment will directly measure the effects of intentions independent of both giver sacrifice and uncertainty.

Two papers have similarly introduced noise into a gift-exchange game [8,25]. However, these studies introduced noise in how the reciprocator could respond (i.e., noise in the worker’s effort in the gift-exchange game), and they were not designed to measure reciprocity to intentions independent of changes in outcome. Thus, these studies are testing a different set of hypotheses than this experiment.

2. Experimental Design and Procedure

2.1. Gift Items

This experiment used three gift items, all of which were represented in the experiment via images on subject computers. The first, a small-value item, was a pen with a market value of approximately $2. The second, a large-value item, was a duffel bag with a market value of $12. Both of these items are commonly used as marketing gifts by firms and non-profits (in fact, these exact items were selected and purchased from a marketing products catalog).2 The third item, similar to monetary-based payoffs in other games, was a cash gift of $2, represented as an image of two one-dollar bills. Whenever a subject received an item, a picture of the item was shown. Figure 1 displays the exact pictures that were shown to all subjects.

2.2. Experimental Session Overview

Figure 2 provides an overview of all of the tasks involved in each experimental session. Each of these tasks will be described in turn.

2.3. Dictator Game Procedure

After seating subjects at computers and giving a standard welcome message, subjects were randomly assigned (by zTree, [26]) to one of two roles for the experiment: role 0 or role 1. These corresponded to the dictator and their partner (henceforth referred to as the gift-giver role), although they were only referred to as role 0 and role 1 during the session. Subjects were told that for each task they performed, the computer would randomly and anonymously pair them with a subject of the other role. Subjects were informed that they would retain their role throughout the experiment.

This was followed by Parts I–III, which each corresponded to one of three treatments. The order in which subjects played each of these treatments was randomized, but every subject played all three. Similar within-subjects designs have been used in other modified dictator games [27], and this setup enables more precise measures of reciprocity via subject random effects estimation [28]. Instructions for Parts I–III were printed on handouts for subjects (see Appendix B) and were read to them before each part began.

One of these three parts, the gift treatment, was designed to measure reciprocity to gifts. To begin, the gift-giver was endowed with an item with three-fourths probability. If a gift was endowed, a picture of the item would appear on the gift-giver’s screen, but the dictator would not know whether their partner had an item. The gift-giver could choose whether to give the item to the dictator or keep the item for themselves (see Figure 3a). If they selected yes, the dictator was told that their partner had given them an item, and a picture of the item would appear on the dictator’s screen (Figure 3b). If the item was not given, the dictator would be told that they did not receive an item from their partner (Figure 3c), and they would be reminded that their partner may not have had an item to give.3 The dictator then chose an allocation out of a $10 pie. While the dictator made this choice, their partner was asked how much they expected to be given (but this was not reported to the dictator). This was done to elicit some information about beliefs without risking the possibility of influencing dictator behavior.4 Gift-givers were not informed what their partner allocated that round. Subjects repeated this task eight times, each with a new, random, and anonymous partner. Subjects were told that at the end of the experiment, one of these eight rounds would be selected for payment.

Another of the three parts, the overturned gift treatment, was designed to measure reciprocity to intentions alone. To begin, the gift-giver was again endowed with an item with three-fourths probability, and they again chose whether to give this item to their partner. However, if they gave the item to their partner, nature prevented the gift exchange with one-half probability. When this occurred, it was announced to both players (see Figure 4).5 Dictators then chose how much of a $10 pie to allocate to their partner. Thus, dictators at times made allocation decisions knowing that their partner had attempted to give them an item but were prevented from doing so by nature. While dictators made their choice, gift-givers were again asked what they expected to be given. As before, gift-givers received no feedback on what their partner allocated in that round. Subjects repeated this task for eight rounds, each time with a new, random, and anonymous partner. Subjects were told that one of these eight rounds would be selected for payment.

Another of the three parts was the control treatment that did not include any gift-giving by subjects. This treatment was designed to control for preferences over total wealth distribution. In this treatment, one of the two players was endowed with an item with three-fourths probability. If the dictator was the one endowed with an item, their partner was then informed exactly what item the dictator received (see Figure 5). This is identical in wealth and information to the gift treatment when an item is given to the dictator by the gift-giver.6 This measures how much the dictator allocates simply due to this wealth distribution between players. Without this counterfactual, reciprocity would be confounded with preferences over wealth distribution [29,30,31,32,33,34]. As before, dictators were then asked to make their allocation, while gift-givers were asked what they expected to receive. Gift-givers were not told what their partner allocated in that round. Subjects repeated this task for eight rounds, each time with a new, random, and anonymous partner. Subjects were told that one of these eight rounds would be selected for payment.

Parts I–III consisted of these three treatments in random order, and at the end of the experiment, one round from each treatment (three rounds in total) were selected for payment. More detailed explanations of session implementation are included in Appendix C to aid replication purposes.

2.4. Questionnaire

After the three treatments but before being informed of pay outcomes, subjects filled out a questionnaire. This elicited basic demographics such as age, gender, and race, as well as a scale of Machiavellianism [35]. Subjects were also asked to guess the value of the pen and duffel bag, to rate the desirability of each on a scale of 1–5, and to explain what likely motivated each player’s actions in the game. Finally, subjects were asked to estimate the number of previous economics experiments they had participated in.

2.5. Subject Recruitment

Three sessions were run at CASSEL (California Social Science Experimental Laboratory) in the UCLA Public Affairs building in 2013. Subjects from the CASSEL subject pool were recruited via e-mail. Each session recruited a maximum of 50 subjects, and 90 subjects in total participated across the three sessions, yielding 45 dictators. The CASSEL lab closed in 2013, and as a result a fourth session was run at Caltech SSEL (Social Science Experimental Laboratory) using the SSEL subject pool. Results including these Caltech subjects are included in Appendix A as a robustness check; for simplicity, the main results in the paper will focus on subjects from just the CASSEL subject pool.7

3. Results

There were 90 subjects (45 dictators) across the three UCLA sessions. Each dictator made 24 allocations (eight in each of the gift, overturned gift, and control treatments) for a total of 1080 dictator allocations. For descriptive statistics about subject traits (e.g., age, gender, etc.), see Appendix A.

3.1. Summary Statistics

Figure 6 shows gift-giver behavior by treatment and item. Across all items, gift-givers gave away their item slightly less than half the time. They almost always gave away the pen and rarely gave away the cash gift. Giving patterns were fairly similar between both gift and overturned gift treatments, suggesting that the 50% chance of having a gift overturned did not have a large influence on a gift-giver’s choice. (Figure 6 displays whether gift-givers attempted to give a gift, regardless of whether it was overturned or not). Since gift-givers did not see dictator allocations until the end of the experiment, their gift-giving rates would not have been influenced by dictator allocations.

Figure 7 shows average dictator allocations in each treatment-item pairing. In the control treatment, dictators on average allocated more when receiving any item from the computer than when receiving no item at all, indicating preferences over wealth distribution. When dictators received any item from their partner, they allocated more than when they received the same item from the computer, indicating reciprocity to all items. Reciprocity to the cash gift and the duffel bag had the largest magnitude effects on average, although relative to perceived dollar value, the cash gift likely had a larger effect. Finally, average allocations doubled in response to overturned gifts relative to rounds where the dictator also ended up with no item, indicating reciprocity to just the intention to give a gift. On average there was also no punishment effect when the partner gave no item, since allocations are similar when no gift was given, regardless of whether the gift would have come from the computer or their partner. For histograms of allocations by treatment and item, instead of just averages, see Figure A1 in Appendix A.

3.2. Regression Analysis

To properly account for within-subject variance, the main results use ordinary least squares (OLS) regression models at the subject-round level with subject random effects.8 The dependent variable is dollars allocated by the dictator. The main model, Model (1) in

Table 1. Allocation by Type of Gift Received.

DV = Dollars Allocated	(1)	(2)	(3)	(4)
Specification a	OLS	OLS	Tobit b	OLS
Dictators (Rounds)	45 (1080)	45 (1080)	45 (1080)	45 (1080)
R2	0.120	0.120		0.120
Treatment Indicators
Gift	0.190 (0.125)	0.190 (0.125)	0.435 (0.348)	0.187 (0.123)
Overturned Gift	−0.057 (0.076)	−0.057 (0.076)	−0.265 (0.305)	−0.060 (0.075)
Item Indicators (Wealth Effects)
Has pen	0.560 *** (0.148)	0.560 *** (0.148)	1.463 *** (0.351)	0.563 *** (0.148)
Has $2 item	0.915 *** (0.209)	0.915 *** (0.209)	2.125 *** (0.409)	0.918 *** (0.208)
Has bag	1.037 *** (0.230)	1.037 *** (0.230)	2.256 *** (0.429)	1.048 *** (0.229)
Gift-from-Partner * Item Indicators (Reciprocity Effects)
Given pen	0.283 * (0.164)	−0.336 * (0.204)	0.739 * (0.398)	0.289 * (0.164)
Given $2	0.453 ** (0.198)	−0.167 (0.219)	1.042 ** (0.414)	0.469 ** (0.202)
Given bag	0.617 ** (0.292)	−0.008 (0.305)	0.922 * (0.547)	0.619 ** (0.292)
Gift overturned	0.619 *** (0.167)		1.910 *** (0.446)	0.630 *** (0.169)
Intention-to-give		0.619 *** (0.167)
Partner Expectation				−0.006 (0.008)
Constant	0.529 *** (0.139)	0.529 *** (0.139)	−1.945 *** (0.658)	0.544 *** (0.133)
Subject Random Effects	YES	YES	YES	YES

_a Ordinary least squares (OLS) standard errors (SEs) are robust and clustered by subject. Tobit SEs are bootstrapped (1000 re-samples) and re-sampled by cluster; _b Tobit is left-censored at 0 (676 left-censored observations); * p < 0.10; ** p < 0.05; *** p < 0.01.

, includes indicators that identify what item the dictator ended up with for that subject-round. These indicators estimate the change in a dictator’s allocation caused by simply having additional wealth in the form of each item. These are also interacted with another indicator that specifies whether the item was received from their partner (as opposed to from the computer); these interactions represent reciprocity to the gift-giver once wealth effects are controlled for. The model also includes an indicator representing whether a gift was overturned. Note that if a gift was overturned, the dictator necessarily has no item in their possession. Finally, treatment indicators are added to ensure that, conditional on the above variables, baseline allocations did not differ across treatments. Standard errors are clustered by subject. Models (2)–(5) modify Model (1) in ways that will be explained in subsequent sections.

3.2.1. Wealth Effects

Model (1) affirms that preferences over wealth distribution significantly influenced dictator allocations. The baseline allocation corresponding to when the dictator had no item was $0.53 (the constant term), with no significant difference by treatment (the treatment indicators). Simply possessing the pen increased dictator allocations by another $0.56 on average, approximately doubling the amount allocated relative to possessing no item. Possessing the duffel bag increased allocations by $1.04. Possessing the two-dollar cash item increased allocations by $0.92. All three wealth effects are significant at the p < 0.01 level, suggesting that dictators had clear wealth distribution preferences on average.

3.2.2. Reciprocity to Gifts

Model (1) indicates that, beyond simple wealth effects, receiving an item from the gift-giver caused dictators to reciprocate and allocate even more. Receiving a duffel bag from the gift-giver increased dictator allocations by another $0.62. This effect was in addition to the $1.04 average increase in allocation caused by simply possessing the item; thus, receiving a duffel bag for the gift-giver increased allocations by a net of $1.66 on average relative to rounds with no gift. Receiving the cash item or pen from the gift-giver instead of from the computer increased allocations by $0.45 and $0.28 respectively, although the latter effect is only significant at the p < 0.10 threshold. (It reaches the p < 0.05 threshold when including the aforementioned Caltech subjects; see

Table A2. Allocation by Type of Gift Received (Includes Caltech Session).

DV = Dollars Allocated	(A1)
Specification a	OLS
Dictators (Rounds)	59 (1416)
R2	0.119
Treatment Indicators
Gift	0.170 * (0.099)
Overturned Gift	−0.039 (0.059)
Item Indicators (Wealth Effects)
Has pen	0.566 *** (0.127)
Has $2 item	0.939 *** (0.178)
Has bag	1.151 *** (0.222)
Gift-from-Partner * Item Type (Reciprocity Effects)
Given pen by partner	0.260 ** (0.128)
Given cash by partner	0.612 *** (0.191)
Given bag by partner	0.557 ** (0.262)
Partner’s gift was overturned	0.596 *** (0.145)
Constant	0.604 *** (0.148)
Subject Random Effects	YES

_a All OLS SEs are robust and clustered by Subject. * p < 0.10; ** p < 0.05; *** p < 0.01.

in Appendix A).

3.2.3. Reciprocity to Intentions

When gifts are overturned, dictators reciprocated by allocating $0.62 more to their partner, more than doubling allocations relative to other rounds where the dictator also ended up with no item. In Model (2), the overturned gift indicator is replaced with an “intentions” indicator that takes a value of 1 for any instance where intention-to-give is announced or a gift is exchanged (this simply rearranges the indicator variables into different categories). Not surprisingly, since the overturned gift indicator has such a large coefficient in Model (1), this alternate regression suggests that intentions alone drove all of the observed reciprocity effects on average. In fact, receiving the pen led to marginally less reciprocity than an overturned gift; subjects may have underestimated the likelihood that the overturned gift was a pen, or they may not have given much thought to the identity of the overturned gift. Regardless, the results from both Models (1) and (2) clearly indicate a highly significant effect of intentions on dictator choice.

3.2.4. Punishment for Not Giving

Models (1) and (2) also suggest that dictators did not punish their partners if they did not receive a gift. The treatment indicators are insignificant, suggesting that dictators allocated similarly when they received no item in a round, regardless of which treatment they were in and whether gifts (or overturned gifts) from the gift-giver were even possible in that round. This lack of punishment is likely because dictators were reminded in every no-gift round that their partner may not have had an item to give.

3.2.5. Tobit Specification

Model (3) re-runs Model (1) using a panel Tobit specification that is left-censored at 0. Since dictators could not allocate less than $0, there is significant “piling” at 0 which could skew the results of a linear model. The Tobit specification corrects for this and yields similar results. Reciprocity to the duffel bag does drop to marginal significance (p = 0.08). However, note that there were 10 dictators (out of 45) that always allocated $0 in all 24 rounds. These dictators have no within-group variation; in the random-effects Tobit specification, they are dropped from the within-group analysis, thus leading to biased results. For this reason, main results in this paper use OLS specifications.

3.2.6. Gift-Giver Expectations

Model (4) examines whether controlling for the gift-giver’s expectations over allocations can account for the observed effects. Blanco et al. [11] suggest that guilt-based reciprocity is driven by individuals acting according to how they believe others expect them to act; if a dictator’s beliefs about their partner’s expectations are correlated with their partner’s actual expectations, then this variable may predict reciprocity. However, Model (4) shows that conditional on other factors, partner-expectations are not a predictor of allocations, and all effects from Model (1) are still the same after controlling for partner-expectations. (As explained in a previous footnote, dictator beliefs were not elicited directly out of concern that doing so would bias dictator behavior, so gift-giver expectations were elicited instead).

3.2.7. Effects by Treatment Type

Model (5) in

Table 2. Allocation by Treatment.

DV = Dollars Allocated	(5)
Specification a	OLS
Dictators (Rounds)	45 (1080)
R2	0.119
Treatment Indicators
Gift	0.183 (0.120)
Overturned Gift	−0.049 (0.083)
Item Indicators (Wealth Effects)
Has pen	0.455 *** (0.132)
Has $2 item	0.922 *** (0.219)
Has bag	1.134 *** (0.222)
Gift-from-Partner * Treatment Indicators
Gift * Gift treatment	0.449 *** (0.165)
Gift * Overturned Gift treatment	0.402 ** (0.197)
Partner’s gift was overturned	0.611 *** (0.173)
Constant	0.529 *** (0.139)
Subject Random Effects	YES

_a All SEs are robust and clustered by subject. * p < 0.10; ** p < 0.05; *** p < 0.01.

examines whether dictators responded differently to gifts in different treatments. Since gifts in the overturned gift treatment are prevented with 50% probability, it is possible that dictators could view these gifts as less kindly intended, since they were given with the knowledge that the item might not actually exchange hands (in other words, the ulterior motives may differ between these two treatments). Thus, Model (5) pools all items into a single category and interacts each treatment with an indicator for whether the dictator received any gift from the gift-giver in that round. (Sample sizes are too small to test interactions between each gift item and treatment condition separately).

Model (5) in Table 2 yields similar wealth and reciprocity effects as in Model (1). In addition, a gift from the gift-giver increased allocations by $0.45 on average in the gift treatment and $0.40 on average in the overturned gift treatment (difference is not significant: p = 0.80). Thus, the 50% possibility of a gift-return in the overturned gift treatment did not influence dictators to respond any differently to gifts. Moreover, as displayed in Figure 6, the mix of gifts given in the gift and overturned gift treatments are relatively similar, so dictators are responding to a similar mix of gifts in both treatments. Model (5) not surprisingly also displays similar overturned gift effects as Model (1), as well as a similar lack of punishment effects. Altogether, Model (5) is consistent with the idea that the ulterior motives involved in this context are not significantly interfering with reciprocity.

3.3. Dictator Types

Table 3. Number of Dictators Allocating $0 by Item and Treatment.

Treatment	No Item	Received Item a
Control (From Computer)	26 (58%)	17 (38%)
Gift	22 (49%)	11 (24%)
Overturn c	32 (71%)	12 (27%)
Overturned Gift Rounds	18 (40%) b	N/A
Always Zero	10 (22%)

_a Two of these subjects in the Control and one in the Gift did not always give zero under no item; _b One subject always gave $0 to overturned gifts, but not in control rounds with no items; _c In this treatment, the no-item column corresponds to no item attempted.

displays the number of dictators who allocated $0 in all rounds within a specific item-treatment pair. Twenty-six out of 45 dictators always allocated $0 in the Control treatment when they received no item. In standard dictator games, these subjects would be considered economically rational types, or “econs” for short (Thaler 2000). However, nine of these econs (35% of the 26) allocated positive amounts when the computer gave them an item, suggesting that they have other-regarding preferences in wealth distribution. In the gift treatment, 11 of the 22 that allocated $0 when receiving no item instead allocated positive amounts when receiving a gift from their partner. This suggests that approximately 15% of these subjects have reciprocity-based other-regarding preferences (not necessarily 50%, since 35% may be attributed to wealth distribution preferences). Finally, intentions alone in the Overturned Gift treatment shifted about 30% of econs into allocating positive amounts. This occurred even though an overturned gift should inform dictators that their partner has a gift, thus causing wealth effects to work against increasing allocations.

3.4. Subject Self-Reported Motives

In the questionnaire, dictators were asked why they thought their partner gave them a gift, as well as what motives they had for their allocation choices. To quantify their text responses, nine Amazon Mechanical Turk masters-rated workers coded these responses to determine whether guilt or kindness factored into dictator motives.9 The workers were blinded to the purpose of the study and were asked to simply evaluate the statements. To ensure the workers were coding carefully, ten fabricated responses that very clearly did or did not mention intentions and/or guilt were mixed into the responses; workers coded these statements accurately.

On average, 25% of dictator statements were rated by the coders as mentioning kindness, gratitude, or positive intentions as reasons for why they reciprocated to gifts.10 On the other hand, 20% of dictators on average were coded as listing guilt or obligation as a reason. These responses are consistent with both intentions-based and guilt-based models of reciprocity, suggesting that both mechanisms may have played a role in the observed results. Most importantly, these results affirm the possibility that positive intentions may still be inferred from gifts in a setting where ulterior motives are present.

4. Discussion

This study used a gift-giving task embedded within a dictator game to test for motivators of reciprocity. Subjects reciprocated on average to just the intention to give a gift, and reciprocity to intentions was at least as large in magnitude on average as actually receiving any of the three items (after controlling for wealth distribution preferences). These results are consistent with intentions-based models of reciprocity and suggest that purely the intent to give a gift (without any actual giver sacrifice) can be enough to generate reciprocity. In addition, although it may seem surprising that some individuals reported inferring kind intentions when an ulterior motive was present, this is consistent with research showing that gift recipients do not always draw proper inferences on what the gift-giver’s motives are [18].

These results do not rule out the possible role of guilt-based reciprocity at the individual level in this or other contexts. Alternative models suggest that guilt, obligation, and expectations can also motivate reciprocity [9,10,11], and some dictators referenced these motives when explaining their choices. Nevertheless, this design is better able to distinguish between guilt and intentions mechanisms than existing studies; unlike standard gift-exchange, moonlighting, and trust games, this study demonstrates that reciprocity occurs even in the absence of any potential guilt effects resulting from giver sacrifice. Most importantly, even if guilt-based mechanisms are still present in this context, this would not contradict the main result that intent to give a gift, independent of giver sacrifice or changes in outcomes, can be enough to engender reciprocity, and furthermore that some dictators reported inferring kindness from an overturned gift.

Subjects also reciprocated to both monetary and non-monetary gifts in this context. Unlike some previous studies [13], cash gifts generated more statistically significant and larger magnitude effects than the equivalent non-monetary gift (a pen in this case), even though subjects estimated the pen as having a market value of approximately $2 on average.11 However, subjects may have simply assigned very different utility values to the pen and cash, leading to this discrepancy. In addition, subjects estimated the duffel bag at over seven times the dollar value of the pen ($14.70), yet reciprocity to the duffel bag was only approximately twice that of the pen. As such, there may be decreasing marginal returns, in terms of reciprocity, to increasing the value of a gift. This is potentially consistent with evidence in psychology [36] that the value of a gift does not have great impact on an individual’s emotional response to a gift. This could help explain why firms often use small-value items such as pens, keychains, calendars, or the like as promotional gifts. However, in this context, none of the gifts proved worthwhile for the gift-giver on average, which differs from the returns to gifts in field experiments [17,20]. Follow-up research should therefore continue to bridge the gap between results from laboratory experiments and results from marketing and economics field studies.