a list of sample charities encloses monetary or non

1

Web Appendix A: A list of charities using monetary or non-monetary pre-giving incentives (collected from faculty and staff at the Business School of the authors’ institution)

A list of sample charities encloses monetary or non-monetary PGIs in their donation request letters

Charities enclose monetary PGI Charities enclose non-monetary PGI Abandoned Children's fund American Heart Association Aid for Starving Children Boys Town Care Food For The Poor Children's Hunger Relief Fund Guiding Eyes For the Blind Christian Appalachian Project Habitat for Humanity Covenant House Helen Keller International Food For The Poor Humane Society Jewish Voice Ministries International Make-A-Wish Foundation Leukemia & Lymphoma Society Memorial Sloan Kettering Cancer Center Missionaries of Africa Path Finder International Mothers Against Drunk Driving Ronald McDonald House Charities Orbis Save The Children Paralyzed Veterans of America Sierra Club UNICEF St. Jude Children's Research Hospital Veterans of Foreign Wars United Service Organizations Water for Life World Wildlife Fund

Examples:

2

Web Appendix B. Details for the pilot study

The pilot study had a 2 (organization type: charity, business) X 2 (familiarity of the

organization: familiar, unfamiliar) between-subject design (N = 201, 100 female, Mage = 36.57).

Mturk participants were shown the logos of eight charities or eight for-profit businesses.

Participants in the familiar condition were asked to choose one that was familiar to them, while

participants in the unfamiliar condition were asked to choose one that was unfamiliar. They rated

their chosen organization on four communal items and four exchange items (e.g., this

organization helps people without expecting anything in return; this organization expects people

to reciprocate; Aggarwal 2004). All items were measured on a 7-point Likert scale (1 =

completely disagree, 7 = completely agree). Following Aggarwal (2004), these items were

combined to form a Net Communality Score (the exchange items were reverse coded). The

higher the score, the more communal the organization is perceived to be. As expected, the

interaction was not significant (F(1, 197) = 3.85, p = .11, ηp2 = .01). Only the main effect of

organization type was found (Mcharities = 5.59, Mbusiness = 3.57, F(1, 197) = 137.41, p < .001, ηp2

= .41), suggesting that charitable organizations were perceived as more communally oriented

than business organizations. In addition, the Net Communality Scores for the charitable

organizations were above the mid-point of the scale (t(99) = 14.05, p < .001), indicating that

people perceived charities to be more communally than exchange oriented. The opposite was

true for businesses—the ratings were significantly below the mid-point, which suggests that

people perceive them to be more exchange than communally oriented (t(101) = -3.27, p = .001).

Similar results were found using separate communal and exchange norms. In sum, the results

suggest that people perceive charities to be more communal than businesses regardless of how

familiar these organizations are.

3

Web Appendix C. Opening Rates Results and Comparisons within Each PGI Condition

Study 1 Opening Rate Results

Conditions Letters Unopen throw away

Open without reading

Open and read

Unopen but keep

Within the monetary PGI

condition

Charity letter (monetary PGI) 13 20 38 8

Dental bill 0 2 68 9 SmartShopper 15 6 48 10 Auto esurance 68 4 6 1 Retirement ad 35 7 27 9 Credit card offer 70 2 6 1

Within the non-monetary PGI

condition

Charity letter (non-monetary PGI) 36 17 21 6

Dental bill 1 1 72 6 SmartShopper 15 7 51 8 Auto esurance 62 9 6 3 Retirement ad 28 8 30 14 Credit card offer 62 9 6 3

Within the no PGI condition

Charity letter 40 15 14 12 (no PGI) Dental bill 0 0 71 10 SmartShopper 12 7 53 9 Auto esurance 67 6 4 4 Retirement ad 45 4 24 8 Credit card offer 72 5 1 3

Comparisons of Opening Rate Within Each PGI Condition

Conditions Letters Unopen

throw away

Open without reading

Open and read

Unopen but keep

Within the monetary

PGI condition

Charity letter (monetary PGI) 13 20 38 8 vs. Solicited letter 0 2 68 9

P value <.001 <.001 <.001 0.79 vs. Unsolicited letters 47 5 22 5

P value <.001 0.001 0.009 0.39

Within the non-monetary

PGI condition

Charity letter (non-monetary PGI) 36 17 21 6 vs. Solicited letter 1 1 72 6

P value <.001 <.001 <.001 1.00 vs. Unsolicited letters 42 8 23 7

P value 0.34 0.05 0.72 0.77 Within the no PGI

condition Charity letter (no PGI) 40 15 14 12

4

vs. Solicited letter 0 0 71 10 P value <.001 <.001 <.001 0.21

vs. Unsolicited letters 49 6 21 6 P value 0.15 0.04 0.18 0.13

Note: 1. we averaged the responses for the four unsolicited letters and rounded up/down any non-integer numbers. 2. We used Fisher's Exact test for the cells with 0, and chi-square tests for all the other cells.

Unopen throw away. The number of people who chose to throw away the monetary

PGI/non-monetary PGI/no-PGI appeals without opening was significantly higher than the

solicited letter (all p < .001). The number of people who chose to throw away the monetary PGI

appeal without opening was significantly lower than the unsolicited letters (p < .001). No other

difference was found (ps >.14).

Open without reading. The number of people who chose to open the monetary PGI/non-

monetary PGI/no-PGI appeals without reading was significantly higher than both the solicited

letter (all p = .009) and the unsolicited letters (all ps < .06).

Open and read. The number of people who chose to open and read the monetary

PGI/non-monetary PGI/no-PGI appeals was significantly lower than the solicited letter (all p <

.001). The number of people who chose to open and read the monetary PGI appeal was

significantly higher than the unsolicited letters (p < .001). No other difference was found (ps

>.17).

Unopen but keep. No difference was found between any of the conditions (all ps >.12).

5

Web Appendix D. Pretests for study 2, study 3, study 4, study 5 and study 7, and additional attention check information for study 4

Study 2 pretest

We conducted a pretest to ensure that the monetary and non-monetary incentives were

perceived similarly in terms of cost (to the charity) and value (to the recipient). Seventy

participants from Amazon Mechanical Turk participated in the pretest. Participants were asked to

imagine that they received a charity donation request letter in the mail, and a greeting card (a

quarter) was enclosed in the letter as a gift (a picture of the incentive was presented). For each

incentive, participants first estimated the cost of including the incentive on a $0-$1 slider with an

“other” option provided for text entry, and then rated the benefit they gained from receiving the

incentive on a 7-point Likert scale (1= no benefit at all, 7 = a lot of benefit). The order in which

participants answered questions about the monetary and non-monetary incentive was

randomized. Results indicated that the two incentives were perceived similarly in terms of cost

(Mmonetary = $.34, Mnon-monetary = $.26, F(1, 68) = 2.03, p = .16) and benefit (Mmonetary = 2.69, Mnon-

monetary = 3.17, , F(1, 68) = .225, p = .23).

Study 3 pretest

In the pretest, 32 students from the same university as the main study were asked to

estimate (1) the cost for the charity to send the monetary (two quarters) and non-monetary PGI (a

higher quality greeting card) (between $.25 and $1, in $.25 increments, with an open-ended

“other” option), and (2) the subjective benefit they would get from the monetary and non-

monetary PGI (1 = no benefit at all, 7 = a lot of benefit). The order in which participants rated

the incentives was counterbalanced. Results showed no difference in either the perceived cost

6

(Mmonetary = $.59, Mnon-monetary = $.56, F(1, 31) = .225, p = .64) or perceived benefit (Mmonetary=

3.47, Mnon-monetary = 3.25, F(1, 31) = .225, p = .44) of the two PGIs.

Study 4 pretest

In the pretest, 59 Mturkers were asked to estimate the cost of including each incentive for

the charity (on a $0-$1 slider with an “other” option provided for text entry), followed by a

question on the subjective benefit they gained from receiving each incentive on a 7-point Likert

scale (1 = no benefit at all, 7 = a lot of benefit). Pretest results showed no significant difference

between the monetary PGI and non-monetary PGI for either the perceived cost (M$.25 = $.48,

Mcard = $.64, p = .27) and perceived benefit (M$.25 = 2.64, Mcard = 3.03, p = .38).

Study 5 pretest

Using the same rating scales as previous pretests, 123 Mturkers were presented with an

image of one of four gifts ($.25, one card, $2.50, eight cards) and asked to estimate the cost of

including the gift for the charity on a slider, with an “other” option provided for text entry, as

well as the perceived benefit on a 7-point Likert scale (1 = no benefit at all, 7 = a lot of benefit).

Results showed that one quarter and one greeting card were perceived similarly in terms of costs

and benefits (cost: M$.25 = $.48, Mone card = $.64; benefit: M$.25 = 2.64, Mone card = 3.03; both ps

>.25) while $2.50 and eight greetings cards were perceived similarly (cost: M$2.50 = $1.83, Meight

cards = $1.58; benefit: M$2.50 = 3.58, Meight cards = 3.67; both ps >.35).

Study 7 pretest

7

Using the same rating scales and procedures as the previous pretests, Mturk participants

(N = 103) were presented with either an image of a quarter (monetary PGI) or an image of the

magnet (non-monetary PGI) used in the second field study. Results showed no difference in

perceived cost or benefit between the monetary PGI and the non-monetary PGI (cost: M$.25 =

$.42, Mmagnet = $.37; benefit: M$.25 = 3.15, Mmagnet= 2.88; both ps >.61).

Additional attention check information for study 4

The attention check asked participants to “Please choose ‘not at all’ for this item.”

Including participants who failed the attention check reveals a marginal effect of PGI (Mmonetary =

$12.94, Mnon-monetary = $17.04, Mcontrol = $19.88, F(2, 150) = 2.47, p = .088). Monetary PGI led to

significantly lower donations than no PGI (p = .03), and directionally lower donations than non-

monetary PGI (p = .19).

8

Web Appendix E. Stimuli for all studies Note: to comply with double-blind review, city and state names have been masked to avoid identification of the authors’ institution.

Study 2 Charity appeals for monetary and non-monetary conditions (9,000 people field study)

10

10

11

11

Study 3. Charity appeals for monetary PGI, non-monetary PGI and no PGI

12

12

Note: the greeting card was actually placed at the top of the letter.

13

13

14

14

Study 5. Charity appeals for monetary PGIs ($.25 and $2.50) and non-monetary PGIs (one greeting card and eight greeting cards)

15

15

Study 5 posttest. Charity appeal for high-value non-monetary PGI (eight different gifts)

16

16

Study 6. Charity appeals for three phrasings of monetary PGI, non-monetary PGI and no PGI

17

17

Study 7. Sample charity appeal for the direct mail campaign for recurring donors

18

18

Web Appendix F. Field study costs for study 2 and study 7

Study 2 Cost for 9,000 charity appeals with incentives

Monetary Non-monetary No incentive Big envelope (3,000 each) $116.70 $116.70 $116.70 Return envelope (3,000 each) $96.67 $96.67 $96.67 Color Printing (3,000 each) $365.40 $365.40 $365.40 Postage (3,000 each) $552 $552 $552 Inserting cost $300 $225 $150

Incentive cost (3000 quarters; 3000 greeting cards with small envelopes)

$750 $442 $0.00

Business return cost for each PGI condition 27 response for monetary condition; 11 responses from non-monetary condition; 12 responses from the no incentive condition)

$36.05 $14.69 $16.02

Total cost $2,216.82 $1,812.46 $1,296.79 Average cost per person $0.74 $0.60 $0.43

Study 7 Cost for 2,643 charity appeals with incentives

Monetary Non-monetary No incentive Big envelope (881 each) $114.53 $114.53 $114.53 Return envelope (881 each) $88.10 $88.10 $88.10 Color Printing (881 each) $333.37 $333.37 $333.37 Postage (881 each) $162.99 $162.99 $162.99 Inserting cost $149.67 $149.67 $61.57 Incentive cost (881 quarters; 881 magnets)

$220.25 $183 $0.00

Business return cost for each PGI condition 18 response for monetary condition (the other 4 donated online); 25 responses from non-monetary condition; 19 responses from the no incentive condition)

$24.03 $33.38 $25.37

Total cost $1,092.94 $1,065.34 $785.93 Average cost per person $1.24 $1.21 $0.89

19

19

Web Appendix G. Study 2 and study 7 donation amount results including/excluding people who returned the monetary PGI, and including/excluding the outlier (study 2 only) using the log-transformation

Study 2 results including 15 responses who returned 25 cents Log-transformed Dollar amount

Means and SDs P values Means and SDs

Excluding the outlier

Mmonetary = .30, SD = 1.09; Mnon-monetary = 1.42, SD = .26; Mcontrol = 1.56, SD = .35

Mmonetary vs. Mnon-monetary p = .001; Mmonetary vs. Mcontrol p < .001; Mnon-monetary vs. Mcontrol p = .70;

Mmonetary = $17.48, SD = $25.88; Mnon-monetary = $30.45, SD = $16.35; Mcontrol = $47.50, SD = $34.54

Including the outlier

Mmonetary = .38, SD = 1.14; Mnon-monetary = 1.42, SD = .26; Mcontrol = 1.56, SD = .35

Mmonetary vs. Mnon-monetary p = .002; Mmonetary vs. Mcontrol p < .001; Mnon-monetary vs. Mcontrol p = .70;


Study 2 results excluding 15 responses who returned 25 cents Log-transformed Dollar amount

Means and SDs P values Means and SDs

Excluding the outlier

Mmonetary = 1.54, SD = .28; Mnon-monetary = 1.42, SD = .26; Mcontrol = 1.56, SD = .35

Mmonetary vs. Mnon-monetary p = .36; Mmonetary vs. Mcontrol p = .87; Mnon-monetary vs. Mcontrol p = .28;


Including the outlier

Mmonetary = 1.60, SD = .34; Mnon-monetary = 1.42, SD = .26; Mcontrol = 1.56, SD = .35

Mmonetary vs. Mnon-monetary p = .19; Mmonetary vs. Mcontrol p = .75; Mnon-monetary vs. Mcontrol p = .31;

Mmonetary = $54.23; SD = $51.70; Mnon-monetary = $30.45, SD = $16.35; Mcontrol = $47.50, SD = $34.54

Study 7 results excluding 2 responses who returned 25 cents Log-transformed Dollar amount

Means and SDs P values Means and SDs Mmonetary = 1.70, SD = .44; Mnon-monetary = 1.78, SD = .42; Mcontrol = 2.03, SD = .48

Mmonetary vs. Mnon-monetary: p = .55; Mmonetary vs. Mcontrol: p = .024; Mnon-monetary vs. Mcontrol: p = .07;


20

20

Web Appendix H. Descriptive statistics for studies 2-7

Study Results by Condition

Study Condition Average Donation

Ave. Donation

SD

Response Rate

Study 2 Monetary PGI 0.30 1.09 27 (field study, log-transformed data)

Non-monetary PGI 1.42 0.26 11 No PGI 1.56 0.35 12

Study 3 Monetary PGI 28.76% 37.58% 30 ($5 payment,

students) Non-monetary PGI 47.44% 42.77% 29 No PGI 50% 42.81% 32

Study 4 Monetary PGI $11.83 $10.89 36 ($50 slider,

students) Non-monetary PGI $17.93 $17.41 41 No PGI $19.82 $18.24 42

Study 5 Monetary PGI (low-value)

$3.75

$3.03 32

($10 slider, Mturkers)

Non-monetary PGI (low-value)

$5.59

$4.02 31

Monetary PGI (high-value)

$6.32

$3.21 30

Non-monetary PGI (high-value)

$4.36

$3.51 31

Posttest ($10 slider, Mturkers)

Non-monetary PGI (low value)

$4.52

$3.26 84

Non-monetary PGI (high-value, eight same gifts)

$3.95

$3.19 68

Non-monetary PGI (high-value, eight different gifts)

$4.69

$3.53

78

Study 6 Monetary PGI (return) $4.04 $3.37 86

($10 slider, Mturkers)

Monetary PGI (help) $3.86 $3.04 87 Monetary PGI (gift) $4.28 $3.03 90 Non-monetary PGI $5.22 $3.39 99 No PGI $5.13 $3.53 93

Study 7 Monetary PGI 1.49 0.80 22 (field study, log-transformed data)

Non-monetary PGI 1.78 0.42 25 No PGI 2.03 0.48 19

21

21

Web Appendix I. Means and SDs for Proposed and Alternative Mediators and Relative Indirect Effect of Proposed and Alternative Mediators for Study 4 and Study 6

Means and SDs for Proposed and Alternative Mediators

Study Condition Communal

Norms Exchange

Norms Net

Communality Manipulative

Intent Charity

Inefficiency Mean SD Mean SD Mean SD Mean SD Mean SD

Study 4 (measured before DV)

Monetary PGI 4.71 1.07 3.45 1.29 4.63 0.98 3.46 1.30 4.39 1.11 Non-monetary PGI 5.37 1.18 3.13 1.45 5.12 1.16 2.98 1.11 3.45 1.22 No PGI 5.59 1.16 2.72 1.45 5.44 1.18 2.88 1.23 3.55 1.20

Study 6 (measured after DV)

Monetary PGI (help) 5.65 1.12 3.52 1.66 5.07 1.20 2.83 1.53 4.03 1.69 Monetary PGI (return) 5.26 1.33 3.62 1.76 4.82 1.29 3.75 1.86 4.44 1.60 Monetary PGI (gift) 5.33 1.19 3.90 1.57 4.71 1.15 3.37 1.55 4.23 1.56 Combined monetary PGIs 5.41 1.23 3.69 1.67 4.86 1.22 3.32 1.69 4.23 1.62 Non-monetary PGI 5.61 1.12 3.20 1.49 5.20 1.16 2.66 1.29 3.64 1.45 No PGI 5.67 1.10 3.09 1.47 5.29 1.11 2.46 1.21 3.50 1.40

Additional relationship norm results for Study 6 For communal norms, results revealed a significant main effect of PGI (Mmonetary-help = 5.65, Mmonetary-return = 5.26, Mmonetary-gift =

5.33, Mnon-monetary = 5.61, Mcontrol = 5.67; F(4, 502) = 2.80, p = .025, ηp2 = .02). Participants in both the monetary-return condition and

the monetary-gift condition reported lower communal norms than those in the non-monetary PGI or no PGI conditions (monetary-gift vs. non-monetary PGI: p = .087, all other ps < .04). Participants in the monetary-help condition reported higher communal norms than those in the monetary-gift (p = .049) and the monetary-return (p = .017) conditions. No difference was found between any other conditions (all ps > .66). For exchange norms, the main effect of PGI type was also significant (F(4, 502) = 4.33, p = .002, ηp

2 = .03). Participants in both the monetary-return and the monetary-gift conditions reported higher exchange norms than those in the non-monetary PGI or no PGI condition (monetary-return vs. non-monetary PGI: p = .06, all other ps < .02). Participants in the monetary-help condition reported marginally lower exchange norms than those in the monetary-gift condition (p = .09) and marginally higher exchange norms than those in the no PGI condition (p = .055). No difference was found between any other conditions (all ps > .15).

22

22

Relative Indirect Effect for Proposed Mediator and Alternative Mediators

95% Bootstrap CI 95% Bootstrap CI (Study 4) (Study 6)

Mediators in the model Monetary vs. no PGI

Monetary vs. Non-monetary

Monetary vs. no PGI


Relationship Norms

Single mediator:

Net Communality Score 1.56, 8.47 .22, 5.89 .13, .59 .05, .52

Communal norms 2.00, 8.62 .86, 6.83 .004, .51 -.05, .46 Exchange norms .41, 5.74 -.86, 3.75 .06, .40 .04, .35

Dual mediators: Communal norms 1.56, 7.11 .71, 5.72 .003, .51 -.05, .44 Exchange norms -.23, 3.39 -.45, 2.13 -.10, .16 -.09, .13

Manipulative Intent

Single mediator: Manipulative Intent .18, 5.99 -.19, 5.03 .22, .65 .14, .53

Dual mediators: Net Communality Score .85, 6.99 .09, 4.65 .09, .52 .04, .45

Manipulative Intent -.12, 3.79 -.22, 3.01 -.02, .39 -.02, .30

Multiple Mediators: Manipulative Intent -.16, 3.69 -.26, 2.98 -.08, .04 -.10, .04

Communal norms 1.01, 6.19 .48, 5.01 .0002, .51 -.05, .44 Exchange norms -.62, 2.60 -.43, 1.60 -.09, .18 -.08, .15

Charity Inefficiency

Single mediator: Charity Inefficiency 1.10, 6.49 1.45, 6.80 .14, .57 .10, .49

Dual mediators: Net Communality Score 1.16, 7.66 .16, 5.25 .10, .52 .04, .46

Charity Inefficiency -.29, 3.91 -.36, 4.22 -.01, .34 -.02, .29

Multiple Mediators Charity Inefficiency -.11, 3.98 -.18, 4.39 -.02, .33 -.02, .28

Communal norms 1.34, 6.78 .66, 5.52 -.0005, .47 -.05, .42 Exchange norms -.64, 2.59 -.40, 1.64 -.16, .12 -.13, .10

Serial Mediation Analysis (Combined monetary PGI phrasings for study 6)

95% Bootstrap C (Study 4) 95% Bootstrap CI (Study 6)

Serial mediation path Monetary vs. no PGI


Monetary vs. no PGI


PGI type --> Manipulative Intent --> .07, 3.06 -.12, 2.72 .11, .41 .08, .33 Net Communality --> Donation

23

23

PGI type --> Charity Inefficiency --> .41, 4.05 .59, 4.11 .08, .33 .06, .28 Net Communality --> Donation

Separate Mediation Analysis for Each of the Three Monetary Phrasings in Study 6

Monetary-gift

(95% Bootstrap CI) Monetary-return

(95% Bootstrap CI) Monetary-help

(95% Bootstrap CI)

Mediators in the model Monetary vs. no PGI

Monetary vs. Non-

monetary

Monetary vs. no PGI

Monetary vs. Non-

monetary

Monetary vs. no PGI

Monetary vs. Non-

monetary Net Communality Net Communality .24, 1.05 .11, .79 .06, .41 .03, .62 -.03, .18 -.06, .18

Dual Mediation Net Communality .04, .24 .03, .26 .04, .37 .01, .58 -.02, .13 -.04, .15 Manipulative Intent -.04, .14 -.06, .12 -.09, .38 -.23, .55 -.004, .14 -.04, .12

Dual Mediation Net Communality .05, .24 .03, .25 .03, .35 .01, .53 -.03, .18 -.06, .19 Charity Inefficiency -.03, .12 -.05, .11 -.002, .38 - .05, .56 -.05, .10 -.07, .19

Serial Mediation

PGI type--> Manipulative Intent --> Net Communality --> Donation

.04, .17 .02, .16 .07, .37 .07, .54 -.003, .10 -.03, .09

Serial Mediation

PGI type--> Charity Inefficiency--> Net Communality --> Donation

.02, .12 . 01, .12 .04, .25 .02, .38 .03, .40 -.01, .281

Note: 1. The serial mediation in the monetary-help condition using charity inefficiency was significant at the 90th percentile (Monetary vs. non-monetary PGI: B= .10, 90% CI = [.0032, .24]). The serial mediation in the monetary-help condition using manipulative intent was not significant at the 90th percentile.

Serial Mediation (study 4). It is possible that a monetary PGI will lead the charity to be perceived as inefficient or manipulative, which subsequently affects the Net Communality of the charity. Hence, we performed additional analyses to test the possibility of serial mediation from PGI typecharity inefficiency/manipulative intentNet Communality Score donation. Results showed that serial mediation through charity inefficiency and Net Communality was significant (monetary vs. no PGI: B= 1.73, 95% CI = [.41, 4.05]; monetary vs. non-monetary: B= 1.93, 95% CI = [.59, 4.11]). However, serial mediation through manipulative intent

24

24

to perceived communality or vice versa was not significant. This suggests that in addition to the conceptual model we proposed, perceived charity inefficiency also contributes to lower Net Communality, resulting in lower donations. The reversed serial mediation paths were not significant for both manipulative intent and charity inefficiency (all CIs include 0).

Serial Mediation (study 6). As in study 4, we also tested possible serial mediation models. Both serial mediation models (PGI typemanipulative intent/charity inefficiencyNet Communality donation) were significant (see tables above). The reversed serial mediation paths were not significant for both manipulative intent and charity inefficiency (all CIs include 0).

25

25

Web Appendix J. Measures of relationship norms, manipulative intent and charity inefficiency

Relationship norms. In study 4, we used four items adapted from Aggarwal (2004) to

measure communal norms (this organization is concerned about other people’s welfare; this

organization helps people without expecting anything in return; I have warm feelings toward this

organization; this organization does not promptly expect anything in return from those who

benefit from its services) and four items to measure exchange norms (whenever this organization

gives or offers something, it expects something in return; whenever this organization gives or

offers something, it expects comparable benefits in return (value for value); this organization is

behaving like a trader; whenever this organization gives or offers something, it expects quick

return). In study 6, we used the same four communal norm items, and three exchange items. We

reworded some of the exchange items: whenever this organization gives or offers something, it

expects something in return; the organization expects people to reciprocate; this organization is

like a business organization. All items were measured on a 7-point Likert scale (1 = completely

disagree, 7 = completely agree).

Manipulative intent. The manipulative intent measure was adapted from Campbell (1995)

and comprised of four items (1 = completely disagree, 7 = completely agree): The way the

charity tried to persuade people seems acceptable to me (reverse coded); The charity tried to

manipulate donors in ways that I don’t like; I was annoyed by this charity appeal because the

charity seemed to be trying to inappropriately manage or control the donors; I didn’t mind this

charity appeal; The charity tried to be persuasive without being excessively manipulative

(reversed coded).

Charity Inefficiency. Charity inefficiency was measured using the follow three items (1 =

completely disagree, 7 = completely agree): This organization is wasting money; this

26

26

organization is not efficient in using its funding; I wonder how much of my donation will

actually go to the needy people.

27

27

Web Appendix K. Effect of PGI type and PGI value on donation amount (study 5)

$3.75

$5.59 $6.32

$4.36

$0.00$1.00$2.00$3.00$4.00$5.00$6.00$7.00$8.00$9.00

$10.00

Monetary Non-monetary

Donation Amount

$0.25

$2.50

28

28

Web Appendix L. Supplementary study 1 – The anchoring effect

This study tests an alternative explanation for the effect of PGIs on donations—the

anchoring and adjustment heuristic (Tversky and Kahneman 1974), in a lab setting. We test this

hypothesis by explicitly including an anchor across all conditions. If the results are due to

anchoring rather than relationship norms, this should erase the effect of PGI type on donations.

In addition, we utilize two forms of non-monetary PGIs to increase the generalizability of the

effect.

Participants and Procedure

One hundred and sixty-nine Mturkers (71 female, Mage = 35.87) participated in the study.

Participants were randomly assigned to one of four conditions: a charity letter enclosing $0.25, a

greeting card, a pen, or no PGI. Participants were asked to read a charity letter from a fictional

food pantry. The letter stated that the charity was asking for donations to help provide nutritious

food to people in need. All the incentives were placed at the top of the letters. To test the

anchoring effect, the statement “Even $0.25 can help provide a meal” was presented at the top of

the letter across all four conditions.

Measures

After reading the charity letter, participants completed the same communal (α = .81) and

exchange (α = .94) norm measures used in study 4 (Pearson’s r = -.60). Then participants were

told that three people would be randomly selected to receive $10 as an extra show of

appreciation for participating in the study. All participants were asked how much they would be

willing to donate if they receive the $10 by dragging a slider anchored at $0 and $10. This served

as our dependent measure.

Results and Discussion

29

29

Average donation: Participants in the non-monetary PGI pen condition donated similar

amounts as those in the non-monetary PGI card (p = .51) and no PGI (p = .74) conditions, and

more money than those in the monetary PGI condition (p = .01). Since there was no difference

between the pen (Mnon-monetary pen = $3.73) and the card (Mnon-monetary card = $3.29, p = .51), we

aggregated the two non-monetary PGI conditions for subsequent analyses. Consistent with our

hypothesis, PGI type had a significant impact on donations (Mmonetary = $2.03, SD = $2.10; Mnon-

monetary = $3.51, SD = $3.27; Mcontrol = $3.51, SD = $3.20; F(2, 166) = 3.67, p = .027, ηp2 = .04).

Participants in the monetary PGI condition donated significantly less than those in the no PGI

condition (p = .026) and non-monetary PGI condition (p = .011). Donations between the non-

monetary PGI and no PGI conditions did not differ (p = 1.00).

Relationship norms. PGI type had a significant effect on the Net Communality Score

(Mmonetary = 4.39, SD = 1.33; Mnon-monetary = 5.31, SD = 1.31; Mcontrol = 5.65, SD = 1.11; F(2, 166)

= 11.16, p < .001, ηp2 = .12). Net Communality was lower in the monetary PGI condition than in

the non-monetary PGI (p < .001) and no PGI (p < .001) conditions. No difference was found

between the non-monetary PGI and no PGI conditions (p =.15). The effect of PGI type on

communal norms was significant (F(2, 166) = 8.50, p < .001). Monetary PGI led to lower

communal norms than non-monetary PGI (p < .001) and no PGI (p < .001). No difference was

found between the non-monetary PGI and no PGI (p = .50). PGI type also had a significant

impact on exchange norms (F(2, 166) = 9.19, p < .001). Monetary PGI led people to report

higher exchange norms than non-monetary PGI (p = .002) and no PGI (p < .001). The exchange

norm difference between non-monetary PGI and no PGI was marginal (p = .084).

Mediation. We conducted a mediation analysis using 10,000 bootstrap samples (Hayes

2017, PROCESS v3.1. model 4). Consistent with study 3, the indirect effect of PGI type on

30

30

donations through perceived communality was significant between the monetary and no PGI,

and monetary and non-monetary PGI conditions (monetary vs. no PGI: B= .90, 95% CI = [.28,

1.42]; monetary vs. non-monetary: B= .76, 95% CI = [.19, 1.06]).

In sum, this study shows that the effect of PGI type on donations held even when an

explicit anchor was present across all conditions, suggesting that the effect we observed is

unlikely to be explained by anchoring and adjustment. In addition, a different form of non-

monetary PGI (a pen) revealed the same effects as previous studies and provided further support

for the hypothesis that a monetary PGI leads people to donate less than a non-monetary PGI or

no PGI. In comparison, a PGI in a non-monetary format does not evoke exchange norms or

dampen donations as a PGI in monetary format does, which is reflected in donations under both

the non-monetary PGI card and pen conditions.

31

31

Web Appendix M. Supplementary study 2: The effect of PGI type on money and time donations

This is an exploratory study to test how different types of PGIs influence the donation of

time. Research shows that consumers respond differently when thinking about money versus

time (Macdonnell and White 2015). Time is seen as less tangible and is construed in more

abstract terms than money (Macdonnell and White 2015). Moreover, time is personally more

meaningful than money, and motivations and beliefs can lead to very different effects on time

versus money donations (Kulow and Kramer 2016). Further, according to the relationship norms

framework, monetary PGI evokes exchange norms, leads people to donate money in a quid pro

quo manner. Therefore, the decreased donation should reflect more evidently on money donation

than on time donation. In this study, we examine whether the type of donation requested (money

vs. time) is influenced differently by monetary and non-monetary PGIs. In addition, we include

two types of non-monetary incentives to increase generalizability.


Four hundred and forty-five students from a major Midwestern university (227 female,

Mage = 20.51) participated in the study for course credit. The study utilized a 4 (incentive type:

monetary PGI $.25, non-monetary PGI card, non-monetary PGI pen, and no PGI) X 2 (donation

type: money vs. time) between subject design. Participants were asked to read a charity letter

from a fictitious charity, Help Fight Cancer Society. The money appeal asked people to make a

monetary donation (e.g., please make a donation to Help Fight Cancer Society today), and the

time appeal asked for a time donation (e.g., please sign up to volunteer at Help Fight Cancer

Society today).

After reading the letter, half of the participants were asked how much money they were

willing to donate by dragging a slider anchored between $0 and $50, with an “a different

32

32

amount” option available if they wanted to donate more than $50. The other half of the

participants were asked how much time per week they were willing to volunteer at that charity

by dragging a slider between 0 and 10, with “a different number” option available if they wanted

to volunteer for more than 10 hours a week.


We first report the results separately for donations of money and time. Then, to test the

relative contribution of money and time, we converted both dollar amounts and volunteer hours

to a Z score (sperate conversion and then combined given that Z score is affected by range),

which served as our dependent variable for the interaction analysis. Since no differences in

donations were observed between the two non-monetary PGI conditions (money donation: Mnon-

monetary card = $23.95, SD = $19.40, Mnon-monetary pen = $20.68, SD = $19.64, p = .20; time donation:

Mnon-monetary card = 2.84, SD = 2.20, Mnon-monetary pen = 2.78, SD = 2.57, p = .97), we combined them

for the subsequent analysis.

Money donation. Results revealed that PGI type had a significant impact on donations of

money (Mmonetary = $14.50, SD = $12.21; Mnon-monetary = $22.32, SD = $19.50; Mcontrol = $19.69,

SD = $22.21; F(2, 439) = 6.27, p = .002, ηp2 = .03). Participants in the monetary PGI condition

donated significantly less than those in the non-monetary PGI condition (p < .001) and those in

the control condition (p = .041). No difference was found between non-monetary PGI condition

and no PGI condition (p = .23).

Time donation. Results indicated that PGI type had no impact on time donation (Mmonetary

= 2.87, SD = 1.49; Mnon-monetary = 2.79, SD = 2.38; Mcontrol = 2.78, SD = 2.24; F(2, 439) = .001, p

= 1.00, ηp2 < .001). No donation difference was observed between any conditions (all ps > .97).

33

33

Z score Donation. Results from the 3 (incentive type: monetary PGI, non-monetary PGI,

and no PGI) X 2 (donation type: money vs. time) ANOVA revealed an insignificant interaction

(F(2, 439) = 1.88, p = .15, ηp2 = .009).

This study examined the effect of PGI type on time donation, and results showed no

effect of PGI type on time donation.

34

34

Web Appendix N. Supplementary study 3: Effect of PGI on donation amount – free response format

In this study, we examine whether the presence of PGIs can influence donation behavior

in a laboratory setting. Specifically, we aim to test the hypothesis that a low value monetary PGI

will result in lower donations than a non-monetary PGI or no PGI.


One hundred and seventy-seven students (55 female, Mage = 21.98) from a major

Midwestern university participated in the study in exchange for course credit. Participants were

randomly assigned to one of three conditions—a charity appeal with a low value monetary PGI

(a quarter), a low value non-monetary PGI (a greeting card worth $.25), or no incentive. Upon

arrival in the lab, participants were told that they would be participating in a study on charitable

donation; all instructions were computer-based. Participants were asked to read a charity letter

from a fictitious charity, Help Fight Cancer Society. If applicable, PGIs were affixed to the top

of the letter. After reading the letter, participants were asked how much they were willing to

donate using a free response format.


Two participants left the donation amount question blank. Results from the remaining

175 participants revealed an effect of incentive type on donation amount (Mmonetary = $15.79, SD

= $21.56; Mnon-monetary = $38.51, SD = $36.04; Mcontrol = $32.49, SD = $39.01; F(2, 172) = 7.15, p

= .001, ηp2 = .08). Supporting our focal hypothesis, participants in the monetary PGI condition

donated significantly less than those in the non-monetary PGI (p < .001) and no PGI (p < .01)

conditions. Donations in the non-monetary PGI and no PGI conditions did not differ (p = .32).

a list of sample charities encloses monetary or non

Documents