Appendix (For Online Publication)

Time forHelping

Anastasia Danilov and Timo Vogelsang

Appendix (for online publication)

Screenshot of senders’ screen (translated from German)

Statements for the manipulation check(translated from German)

-Not all questions were part of each treatment! --

Please rank the following statements on the scale 1 (strongly disagree) to 7 (strongly agree).

I enjoyed working on the task.
1(strongly disagree)o oooooo 7 (strongly agree)

I worked on the task because I felt ashamed to get up and leave.
1(strongly disagree)o oooooo 7 (strongly agree)

I worked on the task because I had nothing better to do.
1(strongly disagree)o oooooo 7 (strongly agree)

I thought that the recipient could need the money.
1(strongly disagree)o oooooo 7 (strongly agree)

I worked on the task because I felt forced to do so.
1(strongly disagree)o oooooo 7 (strongly agree)

I thought that it would bethe best for both parties toleave the laboratory as soonas possible.
1(strongly disagree)o oooooo 7 (strongly agree)

I had sympathy for the receiverbecause the show-upfee was so low.
1(strongly disagree)o oooooo 7 (strongly agree)

I think that €2.50isappropriate for the 15 minutes that the receiverneeded to stay longer in the laboratory thanme.
1(strongly disagree)o oooooo 7 (strongly agree)

I considered the€2.50 show-up fee in mydecision, without taking intoaccount that the receiverneeds to stay 15 minuteslonger in the laboratory.
1(strongly disagree)o oooooo 7 (strongly agree)

Happiness and volunteering are strongly related.
1(strongly disagree)o oooooo 7 (strongly agree)

Time is a scarce good for me.
1(strongly disagree)o oooooo 7 (strongly agree)

Money is a scarce good for me.
1(strongly disagree)o oooooo 7 (strongly agree)

I worked because I wanted to actively participate in the experiment.
1(strongly disagree)o oooooo 7 (strongly agree)

I fully understood that working has no influence on anything.
1(strongly disagree)o oooooo 7 (strongly agree)

Table A1– Statements for the manipulation check

(1) / (2) / (3) / (4) / (5)
ReLab5 / NoReLab5 / ReLab0 / NoReLab5 / All
I enjoyed working on the task. / 3.13**
(1.98) / 3.03**
(2.07) / 2.05***
(1.4) / 2.27***
(1.61) / 2.69***
(1.86)
I worked on the task because I felt ashamed to get up and leave. / 2.09***
(1.55) / 3.03***
(1.99) / 3**
(1.87) / 2.62***
(2.04) / 2.66***
(1.88)
I worked on the task because I had nothing better to do. / 3.19**
(1.89) / 3.38*
(1.86) / 3.14*
(1.82) / 4
(2.12) / 3.42***
(1.93)
I worked on the task because I felt forced to do so.
/ 3.75
(1.93) / 4.38
(2.09) / 4.52
(2.16) / 4.65
(2.15) / 4.29
(2.08)
I thought that the recipient could need the money.
/ 5.06**
(2.14)
I thought that it would bethe best for both parties toleave the laboratory as soonas possible.
/ 2.22***
(1.45) / 4.1
(2.74) / 2.96***
(2.24)
I had sympathy for the receiverbecause the show-upfee was so low.
/ 4.47
(1.93)
I think that €2.50isappropriate for the 15 minutes that the receiverneeded to stay longer in thelaboratory thanme.
/ 4.63*
(1.7) / 2.67**
(1.62) / 3.85
(1.92)
I considered the€2.50 show-up fee in mydecision without taking intoaccount that the receiverneeds to stay 15 minuteslonger in the laboratory.
/ 4.25
(2.02) / 3.43
(1.91) / 3.92
(2)
Happiness and volunteering are strongly related.
/ 3.78
(1.84) / 4.09
(1.89) / 3.76
(1.97) / 4.31
(1.89) / 3.99
(1.88)
Time is a scarce good for me.
/ 4.78**
(1.54) / 4.56*
(1.63) / 4.86**
(1.65) / 5***
(0.98) / 4.78***
(1.47)
Money is a scarce good for me.
/ 4.84***
(1.42) / 5.34***
(1.54) / 4.19
(1.69) / 5.15***
(1.69) / 4.94***
(1.60)
I worked because I wanted to actively participate in the experiment. / 4.69*
(2.01) / 4.65*
(1.94) / 4.26**
(2.37)
N / 32 / 32 / 21 / 26 / 111

Note: The table reports means and standard deviations for the post-experimental statements. 1 is equal to strong disagreement, 7 equals strong agreement. Significance levels apply to the results from a two-sided Wilcoxon signed rank test compared to the neutral response of 4. *p < 0.1, **p < 0.05, ***p < 0.01.

Additional Tables

Table A2 –Working Time (without controls)

(1) / (2) / (3) / (4) / (5) / (6)
Cox PH model
(Decision to leave the lab at a specific point in time) / OLS
(Working time in minutes) / Probit
(Probability of working time ≥10 minutes)
No recipient in the lab / 1.38
(0.27) / 2.42***
(0.80) / -4.74
(3.45) / -10.96**
(5.28) / -0.05
(0.11) / -0.01
(0.16)
Monetary impact / 0.46***
(0.09) / 0.73
(0.22) / 12.06***
(3.48) / 6.36
(5.05) / 0.63***
(0.11) / 0.67***
(0.16)
No recipient in the lab * Monetary impact / 0.41**
(0.17) / 10.74
(6.93) / -0.08
(0.21)
Controls / No / No / No / No / No / No
N / 111 / 111 / 111 / 111 / 111 / 111
Log likelihood / -411.015 / -408.600
AdjR² / 0.102 / 0.113
Pseudo R² / 0.258 / 0.259

Note: The table reports results from different regressions. Column 1 and 2 estimate the semi-parametric Cox proportional hazard model, 3 and 4 report results from an OLS regression and 5 and 6 use a probit model. Standard errors are reported in parentheses. The hazard ratios are presented as coefficients in the survival models. Marginal effects are shown for the probit model. “No recipient in the lab” is a binary variable equal to 1 in the treatments where recipients were not present in the lab (in NoReLab5 and NoReLab0) and 0 otherwise (in ReLab5 and ReLab0). “Monetary impact” is a binary variable equal to 1 in the treatments (ReLab5 and NoReLab5) and 0 otherwise.*p < 0.1, **p < 0.05, ***p < 0.01

Table A3 – Opportunity Costs and Working Time (without controls)

(1) / (2) / (3) / (4)
Cox PH model
(Decision to leave the lab at a specific point in time) / OLS
(Working time in minutes)
Sender’s WTA / 1.03***
(0.01) / 1.03***
(0.01) / -0.49***
(0.15) / -0.50***
(0.15)
No recipient in the lab / 1.19
(0.24) / 1.99**
(0.67) / -3.62
(3.31) / -10.32**
(5.03)
Monetary impact / 0.47***
(0.10) / 0.72
(0.22) / 9.87***
(3.39) / 3.67
(4.88)
No recipient in the lab * Monetary impact / 0.44*
(0.18) / 11.60*
(6.61)
Controls / No / No / No / No
N / 111 / 111 / 111 / 111
Log likelihood / -404.093 / -402.17
AdjR² / 0.179 / 0.195

Note: The table reports results from a survival analysis using the semi-parametric Cox proportional hazard modeland also from OLS regressions. Standard errors are reported in parentheses. The hazard ratios are presented as coefficients in the survival models. “Recipient in the lab” is a binary variable equal to 1 in the treatments where recipients were present in the lab (in ReLab5 and ReLab0) and 0 otherwise (in NoReLab5 and NoReLab0). “No monetary impact” is a binary variable equal to 1 in the treatments (ReLab0 and NoReLab0) and 0 otherwise. WTA refers to the minimum amount the sender was willing to accept for working for 1 hour on the task. *p < 0.1, **p < 0.05, ***p < 0.01.

Table A4– How do the “Impact Treatments” influence the likelihood of working longer?

Dependent variable: Working time ≥ 10 / (1) / (2)
Probit
No recipient in the lab / -0.01
(0.11) / -0.06
(0.11)
Monetary Impact / 0.65***
(0.12) / 0.61***
(0.11)
Sender’s WTA / -0.02***
(0.01)
Sender’s WTA≥12 / -0.32***
(0.12)
Controls / Yes / Yes
N / 111 / 111
AdjR² / Log likelihood / 0.347 / 0.308

Note: The table reports marginal effects from a Probit regression with the probability to workat least 10 minutes as the dependent variable. Standard errors are reported in parentheses. “No recipient in the lab” is a binary variable equal to 1 in the treatments where recipients were not present in the lab (in NoReLab5 and NoReLab0) and 0 otherwise (in ReLab5 and ReLab0). “Monetary impact” is a binary variable equal to 1 in the treatments (ReLab5 and NoReLab5) and 0 otherwise.WTA refers to the minimum amount the sender was willing to accept for working for 1 hour on the task. Control variables include age, gender and whether or not subjects are studying economics. *p < 0.1, **p < 0.05, ***p < 0.01.

Table A5– Opportunity Costs and Belief about Recipients’ Opportunity Costs

(1)
ReLab5 / (2)
ReLab5
10 minutes / (3)
NoReLab5 / (4)
NoReLab5
>10 minutes / (5)
ReLab0 / (6)
ReLab0
>10 minutes / (7)
NoReLab0 / (8)
NoReLab0
>10 minutes
Sender’s WTA / 13.98
(6.13) / 13.24
(5.85)
/ 17.00
(10.56) / 14.94
(8.92) / 19.36
(10.52) / 10.6
(5.86) / 20.65
(16.76) / 14.33
(4.98)
Belief about time costs of recipient / 9.13
(2.33) / 9.04
(2.52) / 12.45
(8.31) / 10.62
(3.62) / 14.87
(9.79) / 10.25
(5.62)
N / 32 / 26 / 32 / 27 / 21 / 5 / 26 / 6

Note: The table reports means of the sender’s WTA and her belief about the time costs of her recipient. WTA refers to the minimum amount the sender was willing to accept for working for 1 hour on the task (incentivized). “Belief about time costs of recipient” is the sender’sunincentivizedbelief from the ex-post questionnaire about how much one hour is worth for the recipient. This belief wasn’t elicited in the NoReLab0 treatment.

Table A6– Opportunity Costs and Minutes Spent in the Lab

(1)
ReLab5 / (2)
NoReLab5 / (3)
ReLab0 / (4)
NoReLab0 / (5)
All
WTA≥
12 / WTA<
12 / WTA≥
12 / WTA<
12 / WTA≥
12 / WTA<
12 / WTA≥
12 / WTA<
12 / WTA≥
12 / WTA<
12
Overall averages of minutes worked / 19.07
(15.02) / 29.34
(14.23 / 19.2
(16.46) / 30.23
(11.41) / 5.72
(9.33) / 86.08
(7.91) / 5.01
(6.15) / 9
(11.35) / 12.44
(14.15) / 29.83
(22.40)
Averages of minutes worked conditional on spending more than 10 minutes / 23.43
(14.17) / 31.54
(12.08) / 25.36
(16.01) / 32.39
(9.04) / 29.75
(8.49) / 86.08
(7.91) / 15.44
(3.84) / 27
(2.83) / 23.65
(13.97) / 37.19
(19.59)
Proportion of senders who spent less than 10 minutes / 0.13 / 0.03 / 0.19 / 0.03 / 0.76 / 0 / 0.44 / 0.23 / 0.36 / 0.07

Note: The table reports descriptive statistics depending on the treatment and sender’s WTA. WTA refers to the minimum amount the sender was willing to accept for working for 1 hour on the task (incentivized).

Instructions and Invitations

Invitation Email

Hello (name),

We would like to invite you to a new experiment.

The following dates are available:

(dates)

Please note that the duration of the experiment depends on your decision and on the decisions of the other participants. Thus, the duration of the experiment can be between 15 minutes and 2 hours 15 minutes.

The directions to the lab can be found here

If you want to participate, please register under the following link.

Please note that you should only register if you really want to participate. A withdrawal is not permitted under the rules of the laboratory

Instructions for senders

Provided on the computer screen. The text in the angled brackets was not shown the subjects.

Welcome

In all treatments

Welcome, and thank you for participating in today’s experiment.

Please make sure that you are in the correct cubicle!

You will receive the instructions in a moment. These instructions will explain the decision-making situations to you. Please read them carefully. If you have any questions, please don’t hesitate to signal this by clicking on the help button located on the left edge of the screen. We will be glad to help you.

Endowment

In all treatments

At the beginning of the experiment you receive an endowment of €10.

We ask you to please take the endowment and sign the receipt before you make any decisions.

Your endowment and the receipt are located in an envelope under your keyboard. Please fill in the receipt with your name and your signature. Afterwards, please take the money, put the receipt back in the envelope, and - at the end of the experiment - put this envelope in a box near the exit. This box is labelled with “receipts.”

Complete anonymity is guaranteed. This means that it won’t be possible for the experimenter to create any link between your name and your decisions after the experiment. Moreover, other participants won’t learn your identity.

Please click on the button “filled in” to go on.

Information

In all treatments

Please read the following instructions carefully. They will explain what decisions you need to make in the course of the experiment. If you have any questions, please don’t hesitate to signal this by clicking on the help button located on the left edge of the screen. We will be glad to help you as soon as possible.

Any form of communication during the experiment is prohibited. This applies to verbal as well as electronic communication. Please turn off your mobile phone and any other electronic devices and don’t use the Internet. Non-compliance will lead to exclusion from this and futureexperiments.

Furthermore, you are not allowed to do anything (e.g., read a book) except what is stated in the instructions. Non-compliance will lead to exclusion from this and futureexperiments as well.

Please pay continuous attention to the computer screen.

Experiment

In the ReLab5 and in the ReLab0 treatments only

There are 2 different types of participants - participant A and participant B. The cubiclenumber randomly determines the type assigned to a participant. You are participant A.

All participants are divided into groups of 2. Each participant A is randomly assigned to one participant B. Unlike you, participant B will get her payout at the end of the experiment in cash.

In the NoReLab5 treatment only

There are 2 different types of participants - participant A and participant B. You are participant A. Another randomly selected participant is participant B.

All participants are divided into groups of 2. Each participant A is randomly assigned to one participant B. Unlike you, participant B will not be present in the laboratory today. She will participate in this experiment on another day. She will receive her paymentat that time.

In the ReLab5 and NoReLab5 treatments only

The amount depends on your decision.

In alltreatments

All group assignments, payouts, and decisions are anonymous in this experiment.

This means that no participant will ever learn the identity of the others. Similarly, it is not possible for the experimenter to match your decision with your identity.

Furthermore, the participants were invited at different times. This can result in disturbances during the experiment (e.g., people who arrive at or leave the experiment). Don’t let this disturb you.

Decision

In alltreatments

You have already received your endowment of €10. The €2.50 show-up fee is included in this €10. You definitely keep your endowment, i.e., you don’t need to pay anything back.

In the ReLab5, NoReLab5 and ReLab0 treatments

Participant B of your group of two In ReLab5 and ReLab0: has not / In NoReLab5: will notreceive(d) any payment at the beginning of the experiment. Participant B will only receive the €2.50 show-up fee at the end of the experiment.

In the ReLab5 and NoReLab5 treatments only

You now have the possibility to increase the payment to participant B. Therefore, a window will appear on your computer screen to type the combination “1122334455” and confirm with “OK.” 15 seconds after you have successfully typed the combination and confirmed with “OK,” the same window will appear again. For every time you successfully type the combination and confirmed with “OK,” participant B will receive 5 Eurocent. Participant B of your group will get the amount of money acquired at the end of the experiment in cash.<In NoReLab5 only: As explained above, participant B is not present in the lab today. He will participate on another day. You can work on this task a maximum of two hours.

In the ReLab0 and NoReLab0 treatments only

You don’t have any possibility to increase the payment to participant B. A window will appear on your computer screen to type the combination “1122334455” and confirm with “OK”. 15 seconds after you have successfully typed the combination and confirmed with “OK” the same window will appear again. You can work on this task a maximum of two hours.

Typing in the required number and confirming with “OK" has no influence on your payoff or the payoff of any other participant. You can work on this task a maximum of two hours.

In the ReLab5, NoReLab5 and ReLab0 treatments

You can end the experiment at any point by clicking the button “Exit”. We then ask you kindly to fill in a short questionnaire, and hereafter you can leave the laboratory. Please note that the entrance is not the exit. The exit is at the other end of the lab. You maintain your anonymity while you are leaving. Outside of the lab a privacy shield between the entrance and the exit will give you further anonymity.

You will receive different types of information while you are working on the task. On the top left you will see an approximate (!) minutes display, and on the top right you will see an exact seconds display. Below the seconds display you will see the amount of money already earnedfor participant B.

For senders in the ReLab5 ReLab0 treatments only

Participant B has no possibility to increase her payment. Due to her show-up fee of €2.50, she is obligated to stay in the lab as long as you do plus an additional 15 minutes. Participant B is allowed to use the Internet while you are working. During the last 15 minutes of her time (the time after you have left the lab), it is prohibited that participant B uses the Internet.

For senders in the NoReLab5 treatment only

Participant B has no possibility to increase her payment. Due to her show-up fee of €2.50, she is obligated to stay in the lab for 15 minutes.

Payment

For senders in the ReLab5 and NoReLab5 treatments

The payment fortoday’s experiment is as follows:

Your payment: €10

Payment of participant B of your group: €2.50 + €0.05*Amount of windows you have confirmed with the required combination and “OK”

In the following you will receive some questions to test your understanding and a test screen. Afterwards, the experiment will start.

For senders in the ReLab0 and NoReLab0treatments

The payment of today’s experiment is as follows:

Your payment: €10

Payment of participant B of your group: €2.50

In the following you will receive some questions to test your understanding and a test screen. Afterwards, the experiment will start.

Example of the instructions for recipients (in the ReLab5 and ReLab0 treatments)

Provided on the computer screen. The text in the angled brackets was not shown the subjects.

Welcome

In all treatments>

Welcome, and thank you for participating in today’s experiment.

Please make sure that you are in the correct cubicle!

Information

In all treatments>

Experiment

In all treatments>

There are 2 different types of participants - participant A and participant B. The cubiclenumber randomly determines the type assigned to a participant. You are participant B.

All participants are divided into groups of 2. Each participant A is randomly assigned to one participant B. Participant B will get her payoff at the end of the experiment in cash.

All group assignments, payoffs, and decisions are anonymous in this experiment.

This means that no participant will ever learn the identity of the others. Similarly, it is not possible for the experimenter to match your decision with your identity.

Instructions

In all treatments>

Participant A has already received an initial amount of €10 at the beginning of the experiment. The €2.50 show-up fee is included in this €10. You also receive an amount of €2.50 for participation at the end of the experiment. However, you will not receive any additional money at the beginning and you need to stay in the laboratory as long as participant A, plus an additional 15 minutes.

For receivers in the ReLab5 treatment

In the courseof the experiment, participant A has an opportunity to increase your payment. To do this he has to type the numbercombination “1122334455” and confirm thiswith “OK”. 15 seconds after she has successfully typed the combination and confirmed with “OK” the same window will appear again. She can work on this task a maximum of two hours.Each time the participant confirms the correctcombination with “OK,” you will receive 5 Eurocents.