ArticlePDF Available

Neural Responses to Taxation and Voluntary Giving Reveal Motives for Charitable Donations

Authors:

Abstract and Figures

Civil societies function because people pay taxes and make charitable contributions to provide public goods. One possible motive for charitable contributions, called “pure altruism,” is satisfied by increases in the public good no matter the source or intent. Another possible motive, “warm glow,” is only fulfilled by an individual's own voluntary donations. Consistent with pure altruism, we find that even mandatory, tax-like transfers to a charity elicit neural activity in areas linked to reward processing. Moreover, neural responses to the charity's financial gains predict voluntary giving. However, consistent with warm glow, neural activity further increases when people make transfers voluntarily. Both pure altruism and warm-glow motives appear to determine the hedonic consequences of financial transfers to the public good.
Content may be subject to copyright.
DOI: 10.1126/science.1140738
, 1622 (2007); 316Science
et al.William T. Harbaugh,
Reveal Motives for Charitable Donations
Neural Responses to Taxation and Voluntary Giving
www.sciencemag.org (this information is current as of December 11, 2007 ):
The following resources related to this article are available online at
http://www.sciencemag.org/cgi/content/full/316/5831/1622
version of this article at:
including high-resolution figures, can be found in the onlineUpdated information and services,
http://www.sciencemag.org/cgi/content/full/316/5831/1622/DC1
can be found at: Supporting Online Material
found at:
can berelated to this articleA list of selected additional articles on the Science Web sites
http://www.sciencemag.org/cgi/content/full/316/5831/1622#related-content
http://www.sciencemag.org/cgi/content/full/316/5831/1622#otherarticles
, 8 of which can be accessed for free: cites 26 articlesThis article
4 article(s) on the ISI Web of Science. cited byThis article has been
http://www.sciencemag.org/cgi/content/full/316/5831/1622#otherarticles
1 articles hosted by HighWire Press; see: cited byThis article has been
http://www.sciencemag.org/cgi/collection/psychology
Psychology
: subject collectionsThis article appears in the following
http://www.sciencemag.org/about/permissions.dtl
in whole or in part can be found at: this article
permission to reproduce of this article or about obtaining reprintsInformation about obtaining
registered trademark of AAAS.
is aScience2007 by the American Association for the Advancement of Science; all rights reserved. The title
CopyrightAmerican Association for the Advancement of Science, 1200 New York Avenue NW, Washington, DC 20005.
(print ISSN 0036-8075; online ISSN 1095-9203) is published weekly, except the last week in December, by theScience
on December 11, 2007 www.sciencemag.orgDownloaded from
The scaffold protein Dvl was previously thought
to act downstream of LRP6 because dsh over-
expression activates ß-catenin signaling in Drosoph-
ila LRP6 (arrow) mutants (23) and because the
constitutively active Dfz2-Arrow fusion protein is
inactive in dsh mutants (24). The explanation for this
discrepancy may be that overexpressing Dsh/Dvl
leads to artificial sequestration of Axin or that the
protein has multiple functions in the Wnt pathway.
Taken together, the results suggest that Dvl-
mediated co-aggregation triggers LRP6 phos-
phorylation by CK1g. In this model (Fig. 4D),
upon Wnt signaling Dvl aggregates form at the
plasma membrane, where they co-cluster LRP6
with other pathway components including Fz,
Axin, and GSK3b, in a LRP6-signalosome.
The role of Wnt would be to bridge LRP6 and
Fz (25, 5), which copolymerize on a Dvl plat-
form. Clustering of LRP6 then provides a high
local receptor concentration that triggers phos-
phorylation by CK1g and Axin recruitment.
Predictions of this model are as follows: (i)
artificial oligomerization of LRP6 should activate
the receptor and (ii) oligomerized LRP6 should
signal independent of Dvl. Indeed, forced oligo-
merization of LRP6 using a synthetic multimerizer
is sufficient to induce Wnt signaling, and this
oligomerization bypasses the need for Dvl (25).
(iii) Constitutively active LRP6 should signal
independently of Dvl because its self-aggregation
should bypass the need for Dvl polymers. This is
also the case as shown in reporter assays with Dvl
siRNA knockdown (fig. S5, B and C), which
supports previous findings (26, 25). (iv) If LRP6
aggregation is a prerequisite for phosphorylation
by CK1g rather than its consequence, LRP6
aggregates should form even when the kinase is
blocked. This is the case: Nonphosphorylated
LRP6 aggregates were observed in response to
Wnt treatment in cells transfected with dominant-
negative CK1g (Fig. 4C). The model of LRP6-
signalosomes not only provides a mechanism
for Wnt signal transduction but may also be
relevant for the understanding of intracellular
transport of maternal Wnt det erminants in the
fertilized Xenopus egg (27).
References and Notes
1. P. Polakis, Genes Dev. 14, 1837 (2000).
2. R. T. Moon, B. Bowerman, M. Boutros, N. Perrimon,
Science 296, 1644 (2002).
3. C. Y. Logan, R. Nusse, Annu. Rev. Cell Dev. Biol. 20, 781
(2004).
4. R. T. Moon, A. D. Kohn, G. V. De Ferrari, A. Kaykas,
Nat. Rev. Genet. 5, 691 (2004).
5. X. He, M. Semenov, K. Tamai, X. Zeng, Development 131,
1663 (2004).
6. N. S. Tolwinski, E. Wieschaus, Trends Genet. 20, 177 (2004).
7. G. Davidson et al., Nature 438, 867 (2005).
8. X. Zeng et al., Nature 438, 873 (2005).
9. J. Klingensmith, R. Nusse, N. Perrimon, Genes Dev. 8,
118 (1994).
10. K. Itoh, B. K. Brott, G. U. Bae, M. J. Ratcliffe, S. Y. Sokol,
J. Biol. 4, 3 (2005).
11. C. C. Malbon, H. Y. Wang, Curr. Top. Dev. Biol. 72, 153 (2006).
12. J. Mao et al., Mol. Cell 7, 801 (2001).
13. H. Yamamoto, H. Komekado, A. Kikuchi, Dev. Cell 11,
213 (2006).
14. J. D. Axelrod, J. R. Miller, J. M. Shulman, R. T. Moon,
N. Perrimon, Genes Dev. 12, 2610 (1998).
15. U. Rothbächer et al., EMBO J. 19, 1010 (2000).
16. T. Schwarz-Romond et al., Nat. Struct. Mol. Biol. 14, 484
(2007).
17. D. G. Capelluto et al., Nature 419, 726 (2002).
18. J. T. Blitzer, R. Nusse, BMC Cell Biol. 7, 28 (2006).
19. S. Kishida et al., Mol. Cell. Biol. 19, 4414 (1999).
20. T. Schwarz-Romond, C. Merrifield, B. J. Nichols, M. Bienz,
J. Cell Sci. 118, 5269 (2005).
21. M. J. Smalley et al., J. Cell Sci. 118, 5279 (2005).
22. A. Cliffe, F. Hamada, M. Bienz, Curr. Biol. 13, 960 (2003).
23. M. Wehrli et al., Nature 407, 527 (2000).
24. N. S. Tolwi nski et al., Dev. Cell 4, 407 (2003).
25. F. Cong, L. Schweizer, H. Varmus, Development 131,
5103 (2004).
26. L. Li, J. Mao, L. Sun, W. Liu, D. Wu, J. Biol. Chem. 277,
5977 (2002).
27. C. Weaver, D. Kimelman, Development 131, 3491 (2004).
28. We thank R. Pepperkok for support in the EMBL Advanced
Light Microscopy Facility; the Nikon Imaging Center at
the University of Heidelberg and M. Boutros and
D. Ingelfinger for help with siRNA experiments; A. Glinka
for advice; N. Maltry for technical help; and J. Axelrod,
A. Helenius, J. Nathans, R. Nusse, T. Schwarz-Romond,
and M. Semenov for reagents. This work was supported by
the European Union (Endotrack) and the Deutsche
Forschungsgemeinschaft.
Supporting Online Material
www.sciencemag.org/cgi/content/full/316/5831/1619/DC1
Materials and Methods
Figs. S1 to S5
Movie S1
1 November 2006; accepted 11 May 2007
10.1126/science.1137065
Neural Responses to Taxation and
Voluntary Giving Reveal Motives
for Charitable Donations
William T. Harbaugh,
1,2
* Ulrich Mayr,
3
* Daniel R. Burghart
1
Civil societies function because people pay taxes and make charitable contributions to provide
public goods. One possible motive for charitable contributions, called pure altruism, is satisfied
by increases in the public good no matter the source or intent. Another possible motive, warm
glow, is only fulfilled by an individual's own voluntary donations. Consistent with pure altruism,
we find that even mandatory, tax-like transfers to a charity elicit neural activity in areas linked to
reward processing. Moreover, neural responses to the charity's financial gains predict voluntary
giving. However, consistent with warm glow, neural activity further increases when people make
transfers voluntarily. Both pure altruism and warm-glow motives appear to determine the hedonic
consequences of financial transfers to the public good.
E
very society needs public goods, but the
mechanisms used to fund them vary. For
example, taxation and government spending
are lower in the United States than in most European
countries, but philanthropy is higher (1). To
economists, this charitable giving is a puzzle:
Money is a good, so why are people willing to give
it away? One possible explanation is in terms of a
pure altruism motive (2). Individuals with such a
motive receive satisfaction from increases in a
public good, such as the provision of basic services
to the needy. This altruistic concern provides a
motive to give, but there is also an incentive to keep
money for oneself, because the cost of such charity
is entirely paid by the giver, whereas the benefits are
spread out over all those people who care about the
needy. Only those people with a very large pure
altruism motive would give voluntarily, and taxation
is the normal social solution to the resulting free-
riding. Pure altruism implies that people should get
some satisfaction even when public goods are
supplied through mandatory taxation, because, by
this account, people care only about how much of
the public good is provided and not about the
process by which the transfer occurs. A second
possible motive for charitable giving is the sense of
agency associated with the act of voluntary giving.
This reward from giving has been termed warm
glow (3, 4). If givers were driven exclusively by
the warm-glow motive, they should derive satisfac-
tion from making a voluntary gift, rather than from
the increase in the level of the public good itself. On
the other hand, taxation should not produce a warm
glow, because paying taxes typically does not
involve a voluntary choice.
The distinction between pure altruism and warm-
glow motives for giving is important for several
reasons. First, if giving is motivated by pure altruism,
tax-funded government expenditures to provide a
public good will reduce private giving, potentially
dollar for dollar, as people cut their voluntary con-
tributions in response to these higher taxes (5). There
should be no similar effect with warm-glow givers,
as their benefit derives from the amount of their gift.
Second, a warm-glow motive for altruism provides
an argument in favor of policies that encourage
voluntary giving, because the warm-glow benefit
provides a reward to the giver that exceeds the ben-
efit from paying an equivalent amount in taxes (6).
Neural evidence may help clarify the relative
importance of pure altruism and warm-glow mo-
tives for charitable giving. Although there is
1
Department of Economics, University of Oregon, Eugene, OR
974031285, USA.
2
National Bureau of Economic Research
(NBER), Cambridge, MA 021385398, USA.
3
Department of
Psychology, University of Oregon, Eugene, OR 974031227, USA.
*To whom correspondence should be addressed. E-mail:
mayr@uoregon.edu (U.M.) or harbaugh@uoregon.edu(W.T.H.)
15 JUNE 2007 VOL 316 SCIENCE www.sciencemag.org1622
REPORTS
on December 11, 2007 www.sciencemag.orgDownloaded from
considerable evidence linking neural activity in
the ventral striatum and the insulae to the pro-
cessing of concrete rewards such as money, food,
and drugs, less is known about how the brain
processes more abstract rewards such as those
often provided by public goods. For money, ac-
tivity in the ventral striatum increases as people
anticipate increases in payoffs and when they
receive unexpected increases in payoffs (7, 8).
Neural responses in the ventral striatum and insu-
lae to information about products and their prices
also predict purchase decisions (9). This work
supports the theory that these areas provide
information on the relative rewards of different
outcomes, which serve as an input to decisions
about consumption and tradeoffs regarding risk
and money (10). Other studies have shown that
activity in the ventral striatum and the insulae is
correlated with more abstract rewards, including
social rewards such as punishing unfair players in
sharing games (11), voluntary contributions to
charities (12, 13), and decisions to trust others
(14, 15). These results motivate our focus on the
ventral striatum and the insulae.
To test for the pure altruism and warm-glow
motives, we used functional magnetic resonance
imaging while subjects played a dictator game.
Subjects received $100 and then made decisions
about whether or not to give money to a local
food bank. They also observed mandatory, tax-
like transfers of their money to the food bank
(Fig. 1, A and B) (16). The behavioral results in
this experiment are consistent with economic
theory and are similar to those reported in earlier
economic experiments (1719). As shown in Fig.
2A, increases in the amounts going to the charity
and decreases in the cost to the giver both in-
creased the likelihood that a voluntary transfer
was accepted. Self-reported satisfaction with the
transaction followed the same pattern in both the
voluntary and the mandatory conditions (Fig. 2B).
To investigate the neural activity associated with
pure altruism, we used data from the mandatory
treatments, which involved exogenous changes in
subject and charity payoffs. Contrasts of parameter
estimates (Fig. 3) show that activation in very
similar areas of the ventral striatum increased with
the monetary payoff to both the subject and to the
charity. Regression analyses to explain activation
data extracted from anatomical regions of interest
(ROIs) show the same result (table S4) (16). This is
the first evidence we know of demonstrating that
mandatory taxation for a good cause can produce
activation in specific brain areas that have been tied
to concrete, individualistic rewards.
The pure altruism model predicts that people
who highly value increases in the charitys payoff,
relative to the value they place on getting money
for themselves, will be more likely to give. The
evidence economists have typically used to support
this model has been indirect: Relative values have
been inferred from observed decisions (20). Our
experiment allowed us to observe brain activation,
in areas known to respond to rewards, as we varied
the money the subject received and the money the
charity received. This provides a direct test of the
model: Do across-subject differences in neural
responses to subject and charity payoffs predict
who is more likely to give to the charity?
We are able to address this question out of
treatment by using neural responses in those
pure mandatory conditions where only the
subject or only the charity got money (orange and
green cells, respectively, in Fig. 1B). These re-
sponses potentially serve as an indicator of how
much subjects valued money for themselves and
for the charity. In fact, regression coefficients
show that subjects with larger activation re-
sponses to money for themselves were less likely
to give to the charity (black columns in Fig. 4A),
and subjects with larger activation responses to
money for the charity were more likely to give
(gray columns in Fig. 4A). To illustrate this rela-
Fig. 1. (A) Study protocol. We scanned 19 fe-
males using functional magnetic resonance im-
aging (fMRI) while they were presented with
transfers that affected their own account (starting
amount, $100) and the account of a local charity.
Half the transfers were mandatory, to resemble
taxation; the other half were voluntary. We ex-
plained that the experimenters would not know
their choices and that one mandatory and one
voluntary transfer would be randomly chosen
and implemented after the experiment. Events
for each trial occurred as presented in the time
line, details are in the supporting online material
(16). After a 1-s fixation dot, the screen revealed
whether this trial's transfer was mandatory or voluntary, as well as the dollar amount change to the
accounts of the subject and the charity. After 9 s, two vertically aligned labels were added in the lower
portion of the screen, specifying the vertically aligned buttons on a response box. For mandatory
transfers, one of the labels read acknowledge and the other invalid button. For voluntary transfers,
one of the labels read accept and the other reject. Label positions varied randomly from trial to trial.
Immediately after the subjects response, a four-point satisfaction rating scale was shown, to which
subjects responded by pressing one of four laterally oriented keys on the button box. The rating scale
disappeared after 6 s, and there was a blank screen for an intertrial period that was randomly jittered
between 6, 7, and 8 s. (B) Study design. The cells show the dollar transfers. Each design cell was im-
plemented three times as a mandatory transfer and three times as a voluntary decision. Orange cells
indicate pure gains to the subject; green cells indicate pure gains to the charity. These pure-gain design
cells from the mandatory condition were used to predict voluntary giving in the purple cells, where there
was a tradeoff between the subject and the charity (see Fig. 4, A and B).
Fig. 2. (A) Subjects' choices
during voluntary transfers as
a function of payoffs to the
subject and the charity. Many
transfers that were costly to
the subject but benefited the
charity were accepted, and the
rate of acceptance increased
as the cost of making a given
transfer declined. (B) Sub-
jective satisfaction ratings as
a function of payoffs to the
subject and the charity, as
well as the voluntary-mandatory factor. Subjective satisfaction increased as transfers increased and costs
decreased and was higher in the voluntary (solid lines) than in the mandatory conditions (dashed lines).
Fig. 3. Neural response in the ventral
striatum to mandatory payoffs for the sub-
ject (yellow), the charity (blue), and both
(green).
www.sciencemag.org SCIENCE VOL 316 15 JUNE 2007 1623
REPORTS
on December 11, 2007 www.sciencemag.orgDownloaded from
tionship graphically, in Fig. 4B we plotted in-
dividual acceptance rates against the difference
between the neural response to pure charity gains
and pure subject gains, pooled over all the re-
gions in Fig. 4A. We also split the sample into
altruists (n = 10) and egoists (n = 9) de-
pending on whether they had a larger neural
response to the charity's payoff or to their own
payoff. Altruists gave money nearly twice as
often as egoists (58% versus 31%, P = 0.015).
This supports the existence of a purely altruistic
motive: The larger a person's neural response to
increases in the public good, no matter the
source, the more likely they will give voluntarily.
How then is voluntary giving different from
tax-like transfers? Reported satisfaction ratings
were about 10% higher for voluntary than for the
mandatory transfers (P < 0.01, see Fig. 2B and
table S2) (16). The neural evidence shows a sim-
ilar result; t tests indicate higher activation in
the caudate (left, P = 0.015; right, P = 0.004); the
right nucleus accumbens (P = 0.01); and the
insulae (left, P = 0.063; right, 0.075) in the case
of voluntary transfers (table S4) (16).
Of course, these results might simply reflect
the basic economic principle that adding choices
cannot make the decision-maker worse off. This
follows because a person who likes the payoffs in
a given mandatory transfer can always obtain that
same result in the corresponding voluntary con-
dition by accepting the transfer. However, if the
subject does not like the proposed transfer, only
the voluntary conditions give them the option of
rejecting it and keeping the money. Overall, 55%
of the voluntary transfers that involved a subjects
giving up money to the charity (purple cells in
Fig. 1B) were rejected. This led to an increase in
the expected payoff to the individual of $13 or
33%, and a decrease in the expected payoff to the
charity of $7 or 10%, relative to the mandatory
condition. So, although the opportunity for free
choice means higher activation in the caudate, the
left nucleus accumbens, and the insulae, as well
as higher payoffs to the individual, it reduced the
level of funding for the public good.
An important question, then, is to what degree
the observed higher activation comes from the
ability to make a choice and to what extent it results
from the differences in payoffs from that choice.
We looked again at the differences in activation
and satisfaction ratings between the mandatory and
voluntary conditions, but this time controlling for
the consequences of rejection by replacing those
payoff changes with $0. The voluntary-mandatory
activation difference remained reliable for the
caudate (left, P = 0.023; right, P = 0.011) and the
right nucleus accumbens (P = 0.042), even after we
controlled for payoffs (table S6) (16). Also,
reported satisfaction was higher for voluntary than
for mandatory transfers after controlling for payoffs
(P < 0.065 for the complete design; P < 0.001
using the cells involving tradeoffs, purple in Fig.
1B). The pure altruism motive for giving, along
with the story about adding choices described
above, would imply that there should be no
mandatory-voluntary differences after controlling
for the payoff effects. Thus, our results suggest that
both the increased payoffs and the ability to choose
lead to increased neural activity and satisfaction.
Previous results have demonstrated that ac-
tivity in the areas we examined is larger when
reward can be linked to one's own actions rather
than to extraneous factors (2124). Our results
extend these findings about the role of agency in
reward-processing to the important situation in-
volving a choice between the subjects private
payoff and the public good. What is not clear
from earlier reports is whether agency-linked
modulation of reward activity is actually asso-
ciated with a modulation of hedonic value. Our
study shows that neural activity in the caudate
and right nucleus accumbens, as well as subjec-
tive satisfaction, is larger in the voluntary than in
the mandatory situation. The fact that this effect
persists even after controlling for payoffs sup-
ports the warm-glow theory of giving (3).
In summary, we find that three very different
thingsmonetary payoffs to oneself, observing a
charity get money, and a warm-glow effect related
to free choiceall activate similar neural sub-
strates. This result supports arguments for a
common neural currency of reward (2529)
and shows that this model can be applied not just
to choice over money, risk, and private con-
sumption goods, but also to more abstract policy
choices involving taxation and charitable giving
(12). Our results are also important for un-
derstanding why people give money to charitable
organizations. First, these transfers are associated
with neural activation similar to that which comes
from receiving money for oneself. The fact that
mandatory transfers to a charity elicit activity in
reward-related areas suggests that even mandatory
taxation can produce satisfaction for taxpayers. A
better understanding of the conditions under
which taxation elicits neural rewards could
prove useful for evaluating the desirability of
different tax policies. Second, we show that the
opportunity for free choice is associated with
increased activity in regions implicated in process-
ing rewards, as well as with higher reported
satisfaction. Furthermore, this effect is not entirely
accounted for by increased payoffs. In the context
of charitable giving, this choice-related benefit is
consistent with a warm-glow motive for giving.
In combination, these results suggest that
both pure altruism and warm glow are important
motives for charitable giving. Future work may
reveal whether the free-choice effect found here
extends to other situations, and under which con-
ditions taxation elicits neural rewards. A related
question is whether people who vote for a tax to
provide a public good get a warm-glow benefit.
Fig. 4. (A) Predicting giving from ac-
tivations in mandatory pure-gain con-
ditions. We created measures of neural
activation in response to pure subject
gain and pure charity gain by averag-
ing activation from the mandatory con-
ditions where the subject received money
at no cost to the charity and where the
charity received money at no cost to the
subject (orange and green cells, respec-
tively, in Fig. 1B). We used these two sets
of activations as independent predictors of
the average acceptance rate in the nine
design cells involving a tradeoff (purple
cells in Fig. 1B). The figure shows stan-
dardized probit regression coefficients from
models including subject and charity stakes
as control variables and neural response to
pure subject gains and pure charity gains as independent predictors. The
dashed lines indicate P = 0.05 significance. Higher response to pure sub-
ject gain was consistently associated with less giving. Higher response to
pure charity gains was consistently associated with more giving. Co-
efficients for individual predictors were reliable in seven out of 12 cases.
(B) Differences in activation predict giving. As an overall measure, we
averaged the neural activation measures across all six brain areas and
computed the difference between neural responses to the charity's pure
gains and the neural responses to the subject's pure gains (orange and
green cells in Fig. 2B). Giving increased as the neural response to pure
charity gains outweighed the neural response to pure subject gains (R
2
=
27%, P = 0.02).
15 JUNE 2007 VOL 316 SCIENCE www.sciencemag.org1624
REPORTS
on December 11, 2007 www.sciencemag.orgDownloaded from
Last, public goods by their very nature are seldom
traded in markets, and so we cannot observe the
prices people will pay and then use these to
measure value. The finding that neural activity
predicts voluntary donations suggests that such
activity could eventually help measure values and
determine optimal levels of public goods.
References and Notes
1. Center for Civil Society Studies, www.jhu.edu/cnp/
research/compdata.html.
2. S. C. Kolm, in Public Economics, J. Margolis and H. Guitton,
Eds. (Macmillan, London, 1969), pp. 145200.
3. J. Andreoni, Econ. J. 100, 464 (1990).
4. W. T. Harbaugh, J. Pub. Econ. 67, 269 (1998).
5. T. Bergstrom, L. Blume, H. Varian, J. Pub. Econ. 29, 25 (1986).
6. P. Diamond, J. Pub. Econ. 90, 897 (2006).
7. W. Schultz, P. Dayan, P. R. Montague, Science 275, 1593
(1997).
8. C. M. Kuhnen, B. Knutson, Neuron 47, 763 (2005).
9. B. Knutson, S. Rick, G. E. Wimmer, D. Prelec, G. Loewenstein,
Neuron 53, 147 (2007).
10. P. W. Glimcher, A. Rustichini, Science 306, 447 (2004).
11. D. J. F. de Quervain et al., Science 305, 1254 (2004).
12. J. Moll et al., Proc. Natl. Acad. Sci. U.S.A. 103, 15623 (2006).
13. D. Tankersley, C. J. Stowe, S. A. Huettel, Nat. Neurosci.
10, 150 (2007).
14. J. K. Rilling et al., Neuron 35, 395 (2002).
15. T. Singer, S. J. Kiebel, S. W. Joel, J. D. Dolan, C. Frith,
Neuron 41, 653 (2004).
16. Materials and methods are available as supporting
material in Science Online.
17. R. Forsythe, J. L. Horowitz, N. E. Savin, M. Se fton,
Games Econ. Behav. 6, 347 (1994).
18. C. C. Eckel, P. J. Grossman, J. Pub. Econ. 87, 681 (2003).
19. J. Andreoni, J. H. Miller, Econometrica 70, 737 (2002).
20. T. R. Palfrey, J. E. Prisbrey, Am. Econ. Rev. 87, 829 (1997).
21. R. Elliott, J. L. Neuman, O. A. Longe, J. F. Deakin,
Neuroimage 21, 984 (2004).
22. J. O'Doherty et al., Science 304, 452 (2004).
23. E. M. Tricomi, M. R. Delgado, J. A. Fiez, Neuron 41 , 281
(2004).
24. C. F. Zink, G. Pagnoni, M. E. Martin-Skurski, J. G. Chappelow,
G. S. Berns, Neuron 42, 509 (2004).
25. P. R. Montague, G. S. Berns, Neuron 36, 265 (2002).
26. B. King-Casas et al., Science 308, 78 (2005).
27. M. R. Delgado, L. E. Nystrom, C. Fissell, D. C. Noll,
J. A. Fiez, J. Neurophysiol. 84, 3072 (2000).
28. B. Knutson, G. W. Fong, C. M. Adams, J. L. Varner,
D. Hommer, Neuroreport 12, 3683 (2001).
29. B. Knutson, C. M. Adams, G. W. Fong, D. Hommer,
J. Neurosci. 21, RC159 (2001).
30. Author contributions: Lead authors hip was determined by
a coin flip between the first two authors. Supported by
the National Institute of Aging R01 AG1929601A1 and
NSF SES-0112157. We would like to thank J. Andreoni,
R. Bryck, T. Cameron, J. Chalmers, C. Rode, M. Taylor,
and S. Frey, as well as the staff at the Lewis Center for
Neuroimaging at the University of Oregon.
Supporting Online Material
www.sciencemag.org/cgi/content/full/316/5831/1622/DC1
Materials and Methods
Fig. S1
Tables S1 to S7
References
2 February 2007; accepted 9 May 2007
10.1126/science.1140738
Sequence Finishing and
Mapping of Drosophila
melanogaster Heterochromatin
Roger A. Hoskins,
1
* Joseph W. Carlson,
1
* Cameron Kennedy,
1
David Acevedo,
1
Martha Evans-Holm,
1
Erwin Frise,
1
Kenneth H. Wan,
1
Soo Park,
1
Maria Mendez-Lago,
2
Fabrizio Rossi,
3
Alfredo Villasante,
2
Patrizio Dimitri,
3
Gary H. Karpen,
1,4
Susan E. Celniker
1
Genome sequences for most metazoans and plants are incomplete because of the presence of
repeated DNA in the heterochromatin. The heterochromatic regions of Drosophila melanogaster
contain 20 million bases (Mb) of sequence amenable to mapping, sequence assembly, and
finishing. We describe the generation of 15 Mb of finished or improved heterochromatic sequence
with the use of available clone resources and assembly methods. We also constructed a bacterial
artificial chromosomebased physical map that spans 13 Mb of the pericentromeric
heterochromatin and a cytogenetic map that positions 11 Mb in specific chromosomal locations.
We have approached a complete assembly and mapping of the nonsatellite component of
Drosophila heterochromatin. The strategy we describe is also applicable to generating substantially
more information about heterochromatin in other species, including humans.
H
eterochromatin is a major component of
met azoan and plant genomes (e. g.,
~20% of the human genome) that regu-
lates chromosome segregation, nuclear organiza-
tion, and gene expression (14). A thorough
description of the sequence and organization of
heterochromatin is necessary for understanding
the essential functions encoded within this region
of the genome. However, difficulties in cloning,
mapping, and assembling regions rich in repeti-
tive elements have hindered the genomic analysis
of heterochromatin (57). The fruit fly Drosoph-
ila melanogaster is a model for heterochromatin
studies. About one-third of the genome is con-
sidered heterochromatic and is concentrated in
the pericentromeric and telomeric regions of
the chromosomes (X, 2, 3, 4, and Y) (5, 8). The
heterochromatin contains tandemly repeated sim-
ple sequences (including satellite DNAs) (9),
middle repetitive elements [such as transposable
elements (TEs) and ribosomal DNA], and some
single-copy DNA (10).
The whole-genome shotgun sequence (WGS3)
was the foundation for finishing and mapping
heterochromatic sequences and for elucidating
the organization and composition of the nonsat-
ellite DNA in Drosophila heterochromatin (5, 6).
WGS3 is an excellent assembly of the Dro-
sophila euchromatic sequence, but it has lower
contiguity and quality in the repeat-rich hetero-
chromatin. We undertook a retrospective analysis
of these WGS3 scaffolds (11). Moderately repeti-
tive sequences, such as transposable elements,
are well represented in WGS clones and sequence
reads, but they tend to be assembled into shorter
scaffolds with many gaps and low-quality regions
because of the difficulty of accurately assigning
data to a specific copy of a repeat. The typical
WGS heterochromatic scaffold is smaller [for
scaffolds mapped to an arm, N50 ranged from 4 to
35 kb (11)] than a typical WGS euchromatic
scaffold (N50 = 13.9 Mb) (5). Relative to the
euchromatic scaffolds, the WGS3 heterochromatic
scaffolds have 5.8 times as many sequence gaps
per Mb, as well as lower sequence quality.
To produce the Release 5 sequence, we iden-
tified a set of 10-kb genomic clones from a li-
brary representing 15× clone coverage by paired
end reads (mate pairs) and used this set as tem-
plates to fill small gaps and improve low-quality
regions (11). Higher-level sequence assembly
into Mb-sized linked scaffolds used relationships
determined from bacterial artificial chromosome
(BAC)based sequence tag site (STS) physical
mapping (see below) and BAC end sequences. In
addition to the WGS data, we incorporated data
from 30 BACs (3.4 Mb; 15 BACs finished since
Release 3) that were originally sequenced as part
of the euchromatin sequencing effort (5, 10).
Sequence finishing resulted in fewer gaps,
longer scaffolds, and higher-quality sequence
relative to WGS3 (fig. S1). About 15 Mb of this
sequence has been finished or improved, and
50% of the sequence is now in scaffolds greater
than 378 kb (N50). Table 1 summarizes the
Release 5 sequence statistics by chromosome
arm. Improved sequence was generated for 145
WGS3 scaffolds, and a set of 90 new scaffolds
were produced by joining or filling 694 gaps of
previously unknown size between WGS3 scaf-
folds. The relationships between the initial WGS
scaffolds and the Release 5 scaffolds can be com-
plex (Fig. 1 and figs. S2 to S7); for example, there
were eight cases in which small scaffolds were
used to fill gaps within larger scaffolds, and two
scaffolds whose gaps interdigitated. As expected,
the sequence consists largely of nests of frag-
1
Department of Genome and Computational Biology,
Lawrence Berkeley National Laboratory, Berkeley, CA
94720, USA.
2
Centro de Biologia Molecular Severo Ochoa,
CSIC-UAM, Cantoblanco 28049, Madrid, Spain.
3
Dipartimento
di Genetica e Biologia Molecolare Charles Darwin,
Universita La Sapienza, 00185 Roma, Italy.
4
Department
of Molecular and Cell Biology, University of California,
Berkeley, CA 94720, USA.
*These authors contributed equally to this work.
To whom correspondence should be addressed. E-mail:
celniker@fruitfly.org
www.sciencemag.org SCIENCE VOL 316 15 JUNE 2007 1625
REPORTS
on December 11, 2007 www.sciencemag.orgDownloaded from
... One motivation for prosocial actions can be the pleasure of receiving rewards for others (Harbaugh, Mayr, & Burghart, 2007;Morelli, Knutson, & Zaki, 2018). A way to operationalize this is through vicarious rewards, that is, rewards that are received for another individual, either in a mutual gaining context or gaining only for others. ...
... Indeed, prior research in adults showed that the ventral striatum is most responsive to rewards for close others relative to distant others (Morelli et al., 2018), and when there is higher social identification with the group (Hackel, Zaki, & Van Bavel, 2017). Together, these studies show that in adults the ventral striatum may be an important marker for the "warm glow" of receiving rewards for others (Harbaugh et al., 2007;Rilling & Sanfey, 2011). Below, we summarize studies that have examined whether adolescence is a time of heightened reward activity, not only for self but also for others. ...
... Third, vicarious rewards can be gained also for more distant prosocial partners with whom the participant does not have a direct connection. One such recipient can be a charity, which typically receives prosocial actions because of the observed need and because charities are considered societal trustworthy recipients (Harbaugh et al., 2007). Using a similar Prisoner Dilemma Game format, one recent study including adolescents aged 11-21-years showed that when gaining vicariously for charity, on the group level charity gains were not associated with increased activity in the ventral striatum (Spaans, Peters, & Crone, 2019). ...
Chapter
Adolescent development is often regarded as a period of social sensitivities, given that brain development continues into the early 20s in interplay with social experiences. In this review, we present adolescence as a unique window for prosocial development; that is, behavior that benefits others. We present evidence for multiple pathways of neural sensitivity that contribute to key developmental processes related to prosocial behaviors, including valuing, perspective taking, and goal-flexibility. Yet, these processes are dependent on several contextual factors including recipients, audience effects, and strategic motivations. Next, we present intervention findings suggesting that prosocial experiences within these various contexts are crucial for adolescents developing into engaged and contributing members of society. These findings suggest a new interpretation of the elevated socio-affective sensitivity and emerging socio-cognitive development in adolescence, focusing on opportunities rather than risks.
... Harbaugh (1998) describes warm glow as a purely internal satisfaction that results in the act of giving. Charity donations induce neural activity in areas connected to reward processing (Harbaugh et al., 2007). Based on the previous discussion, we propose that the positive emotion and content caused by green program participation positively affect the satisfaction judgment of the service experience. ...
... This positive relationship is supported by the results of Erevelles (1998), Harbaugh et al. (2007, and Giebelhausen (2016). ...
Article
Full-text available
Sustainable consumption and green marketing are receiving considerable attention. Nevertheless, the focus of past studies has always been on customer participation, with less attention given to how to satisfy those customers. Also, the focus has been on participants in green programs and not those who choose not to participate. The use of incentives to encourage voluntary green program participation is quite uncommon. The purpose of this research is to examine how manipulating the different types and levels of incentives affect the relationship between voluntary green program participation and satisfaction through the mediating role of warm glow. Three experimental studies were carried out, and data were tested and analyzed using SPSS and PROCESS macro. Results show that the best option to be used by managers to satisfy participants and non-participants of green programs when incentivizing participation is the high self-benefiting incentive. Yet, if this is not feasible, then the second-best option is not to incentivize participation.
... Previous research demonstrated that prosocial actions increase the benefactor's happiness (Aknin et al., 2018;Bierhoff, 2002;Curry et al., 2018). Behavioural studies (Dunn et al., 2008;Nelson et al., 2016) and neurophysiological studies (Harbaugh et al., 2007;Moll et al., 2006) support this link, suggesting that prosocial behaviour such as donating and volunteering is rewarding in itself. With the rewarding effect of prosocial behaviour generally being present, it seems to be not equally rewarding for everybody and dependent, for example, on individuals' values (Hill & Howell, 2014). ...
... It would be valuable to replicate the results with physiological measures of affective consequences, such as rewardrelated brain activity during sharing tasks (cf. Harbaugh et al., 2007). Additionally, requiring a specific behaviour (Sharing, Not-Sharing) reduced participants' autonomy, which in turn might have rendered their emotional states more negative . ...
Article
Full-text available
The moral self-concept has been proposed as a central predictor of prosocial behaviour. In two experiments (one preregistered), we explored the nature of the relation between the moral self-concept (explicit and implicit) and prosocial behaviour. Specifically, we investigated the role of emotions associated with prosocial behaviour (consequential or anticipated) and preference for consistency. The results revealed a relation between the explicit moral self-concept and sharing behaviour. The explicit moral self-concept was linked to anticipated and consequential emotions regarding not-sharing. Importantly, anticipated and consequential emotions about not-sharing mediated the relation between self-concept and behaviour. Yet, the relation was independent of preference for consistency. The implicit moral self-concept was neither related to prosocial behaviour nor to emotions associated with behaviour. Overall, our study demonstrates the interplay between cognitive and emotional processes in explaining prosocial behaviour. More specific, it underlines the link between the moral self-concept and prosocial behaviour and highlights the role of emotions about the omission of prosocial behaviour.
... For example, research on moral "elevation" and "awe" has documented that humans typically gain deeply pleasant and affirming reactions to seeing moral acts, such as compassionate heroism (Haidt 2003, Immordino-Yang 2011. On a neural level, committing or witnessing prosocial acts is associated with activity in the brain's reward networks (e.g., Harbaugh, Mayr, and Burghart 2007). ...
Article
Full-text available
Mencius 孟子 is famous for arguing that human nature is good (xingshan 性善). In this article, I offer a reading of Mencius’ argument which can be evaluated in terms of empirical psychology. In this reading, Mencius’ argument begins with three claims: (1) humans naturally have prosocial inclinations, (2) prosocial inclinations can be cultivated into mature forms of virtue, and (3) the growth of prosocial inclinations is more natural than the growth of their alternatives. I also argue that each of these claims is well supported by empirical psychology. The relevant studies demonstrate, for example, that humans’ prosocial inclinations are not merely products of social conditioning or egoistic concerns; that prosocial inclinations can be cultivated by environmental factors and personal effort; that humans—even preverbal infants—have a natural inclination to prefer prosociality over its alternatives; and that growth in prosociality is positively associated with human health. Finally, I suggest we interpret Mencius’ expression “human nature is good” as a rhetorical tool to capture the totality of such empirically minded claims.
... The model of impure altruism from Andreoni (1989) stipulates that people donate in part because of the ''warm glow'' feeling they experience. Other research has incorporated models of pure altruism (Harbaugh et al. 2007), income and peer effects (Drouvelis and Marx 2021), signaling (Glazer and Konrad 1996;Fehrler and Przepiorka 2013), social pressure and norms (Drouvelis et al. 2019;Andreoni et al. 2017;Krupka and Croson 2016), social information (Shang and Croson 2009), the donor's sense of gratitude (DeSteno et al. 2010;Tsang 2007), the existence and proximity of social connections (Van Dijk et al. 2002;Apicella et al. 2012;Goette et al. 2006), and their current or incidental emotional state (Gneezy et al. 2014;Kandrack and Lundberg 2014;Sollberger et al. 2016;Ibanez et al. 2017). It is this last factor that is the subject of our paper. ...
Article
Full-text available
Many important social and political goals are at least partially funded by charitable donations (e.g. environmental, public health, and educational). Recently a number of laboratory experiments have shown that a potential donor’s incidental emotions—those felt at the time of the decision but unrelated to the decision itself—are important factors. We extend these findings by examining the effect of incidental emotions on charitable giving using a natural field experiment, where the potential donors are unaware of the intervention. In partnership with a pledge drive at a small national liberal arts college, we demonstrate that participants who were asked to recall a person or event that has benefited them since graduating, pledged larger amounts (an increase of 92%) compared to the control group, although the probability of making a pledge was statistically no different.
... There is evidence that giving a gift with a normative motivation does not make consumers feel the same way or provide the same emotional benefits. For example, donors were found to be less satisfied following mandatory donations for public goods than voluntary donations (Harbaugh et al., 2007). When people's prosocial behaviors (e.g., helping others) are not autonomous (e.g., when they emanate from external or self-imposed pressures), psychological benefits and subjective well-being associated with these actions are eliminated (Weinstein & Ryan, 2010). ...
Article
Consumers may self-indulge in luxury for several reasons. This research examines the effect of giving a gift on the giver’s subsequent indulgence in affordable luxury and finds that the motivation underlying gift giving matters: Consumers giving with an altruistic motivation (i.e., to voluntarily make the gift recipient happy) are more likely to self-indulge in affordable luxury than consumers giving with a normative motivation (i.e., to follow a social norm). This effect depends on perceived morality of indulgences, such that willingness to indulge increases to the extent that altruistic gift givers perceive indulgences to be more morally acceptable.
... To the extent that episodic simulation during CBIs reflects situations that an individual encounters during daily life, it prepares the individual to engage compassionately out in the world. Moreover, taking action that successfully alleviates another's suffering during the simulation may elicit reinforcing affective states (e.g., the "warm glow of giving" (Harbaugh et al., 2007;Moll et al., 2006)). ...
Article
Full-text available
Contemplative interventions designed to cultivate compassion are receiving increasing empirical attention. Accumulating evidence suggests that these interventions bolster prosocial motivation and warmth toward others. Less is known about how these practices impact compassion in everyday life. Here we consider one mechanistic pathway through which compassion practices may impact perception and action in the world: simulation. Evidence suggests that vividly imagining a situation simulates that experience in the brain as if it were, to a degree, actually happening. Thus, we hypothesize that simulation during imagery-based contemplative practices can construct sensorimotor patterns in the brain that prime an individual to act compassionately in the world. We first present evidence across multiple literatures in psychology that motivates this hypothesis, including the neuroscience of mental imagery and the emerging literature on prosocial episodic simulation. Then, we examine the specific contemplative practices in compassion-based interventions that may construct such simulations. We conclude with future directions for investigating how compassion-based interventions may shape prosocial perception and action in everyday life.
Chapter
The following chapter analyzes human behavior in the economy. What motivates people, what goals do they pursue and what makes them happy? We need the insights gained to explain unethical behavior and to move people to ethical behavior.
Article
This study aims to elucidate the effects of a prosocial orientation on investments in entrepreneurial businesses through crowdfunding platforms. By drawing on the theory of empathy in social psychology, we focused on social issues that campaigns address, rather than the rhetoric and narratives used in campaigns. We applied a topic modeling method to identify types of social issues expressed in campaign documents. Furthermore, we conducted a questionnaire survey to measure the degree of empathic feeling about social issues. The results revealed that high levels of empathy to social issues do not directly lead to supporting behavior, and in particular, high levels of emotional empathy suppress the effects of cognitive empathy. Instead, backers are more likely to invest in campaigns that address social issues that evoke cognitive empathy and that are perceived to be a viable business.
Article
Full-text available
Instrumental conditioning studies how animals and humans choose actions appropriate to the affective structure of an environment. According to recent reinforcement learning models, two distinct components are involved: a “critic,” which learns to predict future reward, and an “actor,” which maintains information about the rewarding outcomes of actions to enable better ones to be chosen more frequently. We scanned human participants with functional magnetic resonance imaging while they engaged in instrumental conditioning. Our results suggest partly dissociable contributions of the ventral and dorsal striatum, with the former corresponding to the critic and the latter corresponding to the actor.
Article
Full-text available
We consider a general model of the non-cooperative provision of a public good. Under very weak assumptions there will always exist a unique Nash equilibrium in our model. A small redistribution of wealth among the contributing consumers will not change the equilibrium amount of the public good. However, larger redistributions of wealth will change the set of contributors and thereby change the equilibrium provision of the public good. We are able to characterize the properties and the comparative statics of the equilibrium in a quite complete way and to analyze the extent to which government provision of a public good ‘crowds out’ private contributions.
Article
Charities publicize the donations they receive, generally according to dollar categories rather than the exact amount. Donors in turn tend to give the minimum amount necessary to get into a category. These facts suggest that donors have a taste for having their donations made public. This paper models the effects of such a taste for "prestige" on the behavior of donors and charities. I show how a taste for prestige means that charities can increase donations by using categories. The paper also discusses the effect of a taste for prestige on competition between charities. (C) 1998 Elsevier Science S.A.
Article
The capacity to predict future events permits a creature to detect, model, and manipulate the causal structure of its interactions with its environment. Behavioral experiments suggest that learning is driven by changes in the expectations about future salient events such as rewards and punishments. Physiological work has recently complemented these studies by identifying dopaminergic neurons in the primate whose fluctuating output apparently signals changes or errors in the predictions of future salient and rewarding events. Taken together, these findings can be understood through quantitative theories of adaptive optimizing control.
Article
Tax-favored contributions for financing some public goods may be a useful part of optimal nonlinear income tax and expenditure policy. There are two sides to the potential gain from subsidized donations. First, for a given level of public good provision, higher private donations from high earners than low earners eases the incentive compatibility constraint for donors and so can raise social welfare. This follows since considering a lower-paid job includes a perception of a drop in public good provision. Second, private donation reduces consumption, easing the resource constraint. This paper explores optimal policy, using first a model with standard preferences and then a model with a warm glow of giving. In addition to showing the conditions for the level of public goods, the paper considers the pattern of optimal subsidization across earnings levels. Analysis of optimal taxation with warm glow preferences is sensitive to the choice of preferences that are relevant for a social welfare evaluation. After considering optimal rules with formulations of social welfare which do and do not include warm glow utility, the paper considers the choice of normative criterion. Like the earlier literature, this paper assumes that organizing private donations is costless while tax collection has a deadweight burden. Since private charitable fundraising is very far from costless, the paper is an exploration of economic mechanisms, not a direct guide to policy.
Article
The capacity to predict future events permits a creature to detect, model, and manipulate the causal structure of its interactions with its environment. Behavioral experiments suggest that learning is driven by changes in the expectations about future salient events such as rewards and punishments. Physiological work has recently complemented these studies by identifying dopaminergic neurons in the primate whose fluctuating output apparently signals changes or errors in the predictions of future salient and rewarding events. Taken together, these findings can be understood through quantitative theories of adaptive optimizing control.
Article
Research suggests that the basal ganglia complex is a major component of the neural circuitry that mediates reward-related processing. However, human studies have not yet characterized the response of the basal ganglia to an isolated reward, as has been done in animals. We developed an event-related functional magnetic resonance imaging paradigm to identify brain areas that are activated after presentation of a reward. Subjects guessed whether the value of a card was higher or lower than the number 5, with monetary rewards as an incentive for correct guesses. They received reward, punishment, or neutral feedback on different trials. Regions in the dorsal and ventral striatum were activated by the paradigm, showing differential responses to reward and punishment. Activation was sustained following a reward feedback, but decreased below baseline following a punishment feedback.
Article
Reward processing involves both appetitive and consummatory phases. We sought to examine whether reward anticipation vs outcomes would recruit different regions of ventral forebrain circuitry using event-related fMRI. Nine healthy volunteers participated in a monetary incentive delays task in which they either responded to a cued target for monetary reward, responded to a cued target for no reward, or did not respond to a cued target during scanning. Multiple regression analyses indicated that while anticipation of reward vs non-reward activated foci in the ventral striatum, reward vs non-reward outcomes activated foci in the ventromedial frontal cortex. These findings suggest that reward anticipation and outcomes may differentially recruit distinct regions that lie along the trajectory of ascending dopamine projections.
Article
Cooperation based on reciprocal altruism has evolved in only a small number of species, yet it constitutes the core behavioral principle of human social life. The iterated Prisoner's Dilemma Game has been used to model this form of cooperation. We used fMRI to scan 36 women as they played an iterated Prisoner's Dilemma Game with another woman to investigate the neurobiological basis of cooperative social behavior. Mutual cooperation was associated with consistent activation in brain areas that have been linked with reward processing: nucleus accumbens, the caudate nucleus, ventromedial frontal/orbitofrontal cortex, and rostral anterior cingulate cortex. We propose that activation of this neural network positively reinforces reciprocal altruism, thereby motivating subjects to resist the temptation to selfishly accept but not reciprocate favors.