Past-focused environmental comparisons promote
proenvironmental outcomes for conservatives
and Joris Lammers
Social Cognition Center Cologne, University of Cologne, 50931 Cologne, Germany
Edited by Richard E. Nisbett, University of Michigan, Ann Arbor, MI, and approved October 31, 2016 (received for review July 2, 2016)
Conservatives appear more skeptical about climate change and
global warming and less willing to act against it than liberals. We
propose that this unwillingness could result from fundamental
differences in conservatives’and liberals’temporal focus. Conser-
vatives tend to focus more on the past than do liberals. Across six
studies, we rely on this notion to demonstrate that conservatives
are positively affected by past- but not by future-focused environ-
mental comparisons. Past comparisons largely eliminated the po-
litical divide that separated liberal and conservative respondents’
attitudes toward and behavior regarding climate change, so that
across these studies conservatives and liberals were nearly equally
likely to fight climate change. This research demonstrates how
psychological processes, such as temporal comparison, underlie
the prevalent ideological gap in addressing climate change. It
opens up a promising avenue to convince conservatives effectively
of the need to address climate change and global warming.
A spirit of innovation is generally the result of a selfish temper and
confined views. People will not look forward to posterity, who never
look backward to their ancestors.
—Edmund Burke, Reflections on the Revolution in France,1790
Despite strong evidence that humans are causing global
warming (1), there is continuing debate surrounding the
issue. Political ideology has been shown to be the strongest
predictor of politicians’beliefs regarding climate change (2), and
political polarization of beliefs regarding climate change in the
United States has increased in recent years (3). Generally, these
trends are characterized by relatively low and decreasing support
from conservatives (2–4). The link between conservatism and low
support for action addressing climate change can have negative
social and economic consequences. For instance, simply labeling
an energy-efficient product with a message mentioning climate
change can reduce the likelihood that politically conservative
individuals will purchase the product (5). What explains this
stark divide characterized by conservatives’relatively unfavor-
able attitudes and behaviors, and how can it be overcome?
We address this question using insights from research in psy-
chology and propose that the divide can be explained, in part, by
different tendencies in temporal comparisons made by liberals
and conservatives. In particular, conservatives tend to evaluate
the present relative to the way things were in the past. The
tendency for conservatives to be past-focused can be traced to
the origins of conservatism. Attitudes such as those expressed in
the introductory quotation from Edmund Burke, widely regarded
as the philosophical founder of political conservatism, emerged
as a reaction to revolutionary movements that sought to break
radically with tradition (6–8). Thus, conservative ideology can be
traced to the desire to defend the status quo against progressive
change, preferring regressive change instead, whereas liberals seek
to replace present society with a newer system (9).
Research has shown that conservatives more strongly endorse
tradition and conformity and prefer the certainty of the past to
the uncertainty of tomorrow (10). These tendencies play out in
the political arena as well: Republican presidents refer to the
past to a greater extent than Democratic ones in their State of
the Union addresses (11). Moreover, conservatives are said to
feel a romantic or nostalgic longing for the way society was (12,
13), suggesting that conservatives view progressive policies and
ideas as pushing society further away from the cherished past.
Indeed, in public opinion surveys in the United States conser-
vatives consistently show stronger beliefs that the state of society
is in decline (14, 15).
Against this backdrop, a potential problem becomes clear:
Appeals for addressing climate change often adopt a future-fo-
cused temporal perspective. Consider an example from United
Nations Secretary-General Ban Ki-moon: “The clear and present
danger of climate change means we cannot burn our way to
prosperity ...We need to find a new, sustainable path to the
future we want”(16). Similar future-focused messages appear in
Al Gore’s documentary An Inconvenient Truth, which presents
viewers with images of a scorched and dry future earth (17).
What these messages have in common is that they compare the
current state of the Earth against a possible future. Simply put,
these appeals aim to convince the audience that drastic action
against climate change must be taken to create a better future
(or to avoid a worse future).
These future comparisons are speculative and often are ac-
companied by propositions to change the socioeconomic status
quo. Conservatives may find such propositions aversive because
they violate the tenants of conservative ideology. Furthermore, if
conservatives associate progressive change with decline (14, 15),
these future-focused messages are unlikely to be convincing. It
Political polarization on important issues can have dire conse-
quences for society, and divisions regarding the issue of climate
change could be particularly catastrophic. Building on research in
social cognition and psychology, we show that temporal com-
parison processes largely explain the political gap in respondents’
attitudes towards and behaviors regarding climate change. We
found that conservatives’proenvironmental attitudes and be-
haviors improved consistently and drastically when we presented
messages that compared the environment today with that of the
past. This research shows how ideological differences can arise
from basic psychological processes, demonstrates how such dif-
ferences can be overcome by framing a message consistent with
these basic processes, and provides a way to market the science
behind climate change more effectively.
Author contributions: M.B. and J.L. designed research; M.B. and J.L. performed research;
M.B. analyzed data; and M.B. and J.L. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
To whom correspondence should be addressed. Email: email@example.com.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.
www.pnas.org/cgi/doi/10.1073/pnas.1610834113 PNAS Early Edition
follows then that conservatives’relatively low support for action
addressing climate change may not result from an inherent dis-
belief in scientific evidence (18) but could be attributed to a lack
of fit between future-focused environmentalist appeals and
conservatives’dominant past-focused temporal orientation.
Reframing the appeals for addressing climate change to fit
conservatives’ideology has proven successful in changing con-
servatives’attitudes and behaviors. For instance, conservatives
expressed more proenvironmental attitudes and behaviors when
doing so was framed as an obligation to one’s nation (19) or
when climate change was described in terms of “contamination”
and “purity”as opposed to “harm”and “care”(20). Conserva-
tives’skepticism about climate change science decreased if the
solution to climate change was described as supporting capital-
ism (21). In other words, conservatives can become more pro-
environmental when being so aligns with morals and values that
are consistent with their world view.
Our approach is similar: Conservatives can become more pro-
environmental when appeals to address climate change are framed
with a past-focused comparison. Conservatives view the past as better
than the present, so an argument that encourages returning to the
past will be appealing. Furthermore, any proposed changes to society
that are rooted in past comparisons should not be hindered by the
uncertainty and decline that conservatives associate with progressive,
or future-focused, changes. Altogether, a past-focused framing may
encourage conservatives to estimate a greater risk of climate change
because the evidence for climate change provided by a past-focused
comparison fits with their predominant cultural outlook. On the other
hand, future-focused messages may lead conservatives to un-
derestimate the risk of climate change because of a misfit between
the framing of evidence and their typical cultural outlook (22).
To test these hypotheses, we recruited participants online via
Amazon Mechanical Turk (MTurk), a web-based tool for recruiting
and paying participants to perform tasks. MTurk samples tend to
produce results that are as valid and reliable as laboratory-based
samples (23) and have been shown to be as representative of the
United States population as other sampling methods used in po-
litical science research (24–26). To avoid the most critical problem
with Mturk samples—nonnaiveté (27)—participants were barred
from taking part in more than one of our studies. We predicted that
past-focused climate messages would be effective in promoting
proenvironmental attitudes and behaviors among conservatives. All
studies were covered under Institutional Review Board approval
from the Social Cognition Center Cologne, and participants pro-
vided consent by clicking a box on the first page of each study.
Methods and Results
Method. In study 1, participants were randomly assigned to read a
message about climate change that drew a comparison either be-
tween the present and the future (future-focused, e.g., “Looking
forward to our nation’sfuture... there is increasing traffic on the
road”) or between the present and the past (past-focused; e.g.,
“Looking back to our nation’spast... there was less traffic on the
road”). Participants were told that a previous participant wrote the
message in response to a prompt asking the participant to describe a
current social issue. We also randomly varied whether the ostensible
participant self-reported as a liberal or conservative and treated this
variable as a between-subjects factor in our analyses. After reading
Fig. 1. Study 1. (A) Conservatives dislike the future-focused but not past-focused environmental message. (B) Conservatives report more favorable envi-
ronmental attitudes after reading a past-focused message (blue line) than after reading a future-focused message (red line).
Fig. 2. Study 2. A past-focused message (white bars) is most effective in
improving conservatives’proenvironmental attitudes. Temporal focus does
not affect liberals’attitudes. Error bars represent SEs.
www.pnas.org/cgi/doi/10.1073/pnas.1610834113 Baldwin and Lammers
the message, participants evaluated the message and reported their
attitudes about the environment and climate change.
Results.As expected, conservatives evaluated the future-focused
climate change message less positively (b=−0.24, P=0.003),
whereas the opposite was true for the past-focused message (b=
0.19, P=0.026; interaction b=0.42, P<0.001) (Fig. 1A).
Reading a past-focused message also increased conservatives’
proenvironmental attitudes. The association between conserva-
tism and less favorable environmental attitudes was reduced by
almost half in the past-focused condition (b=−0.16, P=0.009)
compared with the future-focused condition (b=−0.35, P<
0.0001; interaction b=0.19, P<0.03) (Fig. 1B). There was no
moderating effect of the ostensible participant’s political orien-
tation on these findings (P>0.47), suggesting that the temporal
framing was effective even when the source of the message was a
member of a political out-group (detailed methods and results
can be found in SI Methods and Results,Study 1).
Method.To isolate further the effect of temporal comparison on
conservatives’attitudes, study 2 exposed participants to the past
and future comparisons from study 1 or to a nonenvironmental
control message about the ISIS terrorist organization. Again the
message was communicated by a participant ostensibly from a
previous study, but in this study all messages were from a self-
reported political moderate. After reading the message, partici-
pants completed the environmental attitude measure from study 1.
Results.As predicted, and in accordance with study 1, we found
that conservatives expressed more favorable attitudes in the past-
focused condition than in the control condition (P=0.007, d=
0.44) or in the future-focused condition although the effect was
not statistically significant (P=0.21). Conservatives’attitudes
were more favorable in the future-focused condition than in the
control condition, but this simple effect also was not significant
(P=0.14). However, conservatives’attitudes increased linearly
across the control, future, and past-focused conditions (b=0.37,
SE =0.14, P=0.007); the past-focused condition was most ef-
fective in bolstering conservatives’proenvironmental attitudes
(Fig. 2). Liberals’attitudes did not differ as a function of tem-
poral comparison (P=0.97). Detailed methods and results can
be found in SI Methods and Results,Study 2).
Method.In study 3 we used a more controlled manipulation of
temporal comparisons by presenting participants with 14 pairs of
photographs said to demonstrate the influence of climate change on
the earth. For example, one set of pictures showed a satellite image
of a river basin either full of water or dried up (Fig. S1). We ma-
nipulated temporal comparisons by describing the photographs as
reflecting changes in the environment from the past to the present
(past-focused condition) or reflecting expected changes in the en-
vironment from the present to the future (future-focused condi-
tion). Participants then reported their proenvironmental attitudes.
Results.As expected, conservatives expressed less favorable attitudes
in the future-focused comparison (b=−0.015, P<0.0001), but this
association was greatly attenuated in the past-focused comparison
(b=−0.007, P=0.011; interaction b=0.008, P=0.03) (Fig. 3).
Importantly, these results remained significant when controlling
for feelings of uncertainty and personal need for closure (e.g.,
intolerance of ambiguity) measured after the manipulation.
Neither of these variables moderated the effect of condition on
environmental attitudes over and above political orientation.
Our findings are not likely explained by any uncertainty caused
by the speculative future-focused images or an aversion to such
speculation. Detailed methods and results can be found in SI
Methods and Results,Study 3.
Method.Study 4a was a pilot test that aimed to determine whether
real environmental charities tend to make past- or future-focused
comparisons, on average. Based on these data, we also aimed to
use some of the charities as stimuli in subsequent studies. We
collected links to websites for 46 existing environmental charities
and asked participants to rate the extent to which a random set of
five charities were past- or future-focused.
Results.Overall, the environmental charities were rated as signifi-
cantly future-focused (P<0.0001, d=2.58), underscoring our
general claim that conservatives’lack of support for action
addressing climate change could be caused by real-world trends in
the temporal framing of the appeals to address climate change.
Detailed methods and results can be found in SI Methods and Re-
Fig. 3. Study 3. Conservatives report more positive environmental attitudes
after viewing past-focused environmental comparisons (blue line) than after
viewing future-focused environmental comparisons (red line).
Fig. 4. Study 4b. Conservatives donate more to the past-focused charity
than the future-focused charity, while this is not the case for liberals. Error
bars represent SEs.
Baldwin and Lammers PNAS Early Edition
Method.In study 4b we used two charities from study 4a as stimuli to
demonstrate that temporal focus can influence liberals’and con-
servatives’donation behaviors. Participants were offered $2 windfall
money and were provided with links to the most past-focused and
most future-focused charities from study 4a. They were asked to
visit the two websites and decide how much of the money to donate
to those charities and how much to keep for themselves.
Results.As expected, conservatives gave less than liberals to the
future-focused charity (P=0.0002, d=0.60) (Fig. 4). However, this
difference was attenuated and was not statistically significant for the
past-focused charity (P=0.17). Moreover, conservatives gave more
to the past-focused charity than to the future-focused charity (P=
0.03, d=0.31) whereas liberals gave equally to each charity [P=
0.90; interaction F(1, 157) =2.51, P=0.12]; detailed methods and
results can be found in SI Methods and Results,Study 4b).
Method.The aim of study 5 was to isolate further the effects of
temporal comparisons on donation behavior by using the pro-
cedure in study 5 but randomly presenting participants with only
one website, either the past-focused charity or the future-focused
charity from study 4b or a nonenvironmental control charity
(cancer research). Participants were given $2 windfall money and
were asked to donate as much or as little to the charity as they chose,
while keeping the rest for themselves.
Results. When comparing donations among conservatives and liberals
separately, we found that conservatives gave more to the past-focused
charity than to the future-focused charity (P=0.03, d=0.38) and
more to the cancer research charity than to the future-focused charity
(P=0.03, d=0.60) (Fig. S2). Conservatives did not differ in their
donations to the past-focused and cancer research charities (P=
0.34). Liberals’donations to each of the three charities did not differ
significantly (past- vs. future-focused, P=0.20; past-focused vs. can-
cer, P=0.10; future-focused vs. cancer, P=0.70).
When comparing conservatives and liberals within each charity
condition, we found that conservatives donated more than liberals
to the cancer charity (P=0.02, d=0.40) but less than liberals to
the future-focused charity (P=0.18, d=0.40), although this effect
did not reach conventional levels of significance. Conservatives
and liberals donated equally to the past-focused charity [P=0.72;
interaction F(2, 395) =3.40, P=0.03]. Detailed methods and
results can be found in SI Methods and Results,Study 5.
Method.To increase experimental control and overcome the issue
that the charities used in studies 4b and 5 inevitably differed in ways
other than their temporal focus, we created two ostensible charities
in study 6 and experimentally manipulated the temporal compari-
son. One charity communicated a past comparison (“Restoring the
planet to its original state”), and the other communicated a future
comparison (“Creating a new earth for the future”)(Fig. S3).
Participants were shown the logos and mission statements of each
charity and then were asked to allocate $0.50 to the charities.
Results.When comparing monetary allocations among conservatives
and liberals separately, we found that conservatives distributed more
to the past-focused charity than to the future-focused charity (P=
0.009, d=0.27). Conversely, liberals distributed more to the future-
focused charity than to the past-focused charity (P=0.002, d=0.31).
When comparing conservatives and liberals’allocation tendencies, we
found that conservatives distributed more than liberals to the past-
focused charity (P<0.0001, d=0.58). Conversely, liberals distributed
more than conservatives to the future-focused charity [P<0.0001,
d=0.58; interaction F(1, 192) =16.13, P<0.0001] (Fig. 5). Detailed
methods and results can be found in SI Methods and Results,Study 6.
Study 7: Meta-Analysis. We were interested in quantifying the size of
the effect of political orientation on proenvironmental attitudes and
behaviors as a function of temporal comparison across our studies.
To this end, we submitted effect sizes from all studies (with the ex-
ception of 4a) to a mixed-effects meta-analysis. Although conserva-
tives were less proenvironmental than liberals overall (d=−0.54, P<
0.001), this difference was modified by temporal comparison (β=
0.64, P=0.01). Conservatives were less proenvironmental than lib-
erals in the future-focused and control conditions (d=−0.82, P<
0.0001), but this difference was attenuated and was no longer statis-
tically significant in the past-focused conditions (d=−0.19, P=0.35).
Past comparisons largely bridged the political divide in addressing
global warming and climate change observed in the future-focused
and control conditions.
Conservative ideology emerged from a resistance to progressive
change, and thus a central feature of conservatives’psychology is a
preference for the past over the future. On this basis, we predicted
and found that past-focused environmental comparisons are more
effective in convincing conservatives of the need to act against climate
change. In fact, the meta-analysis showed that past comparisons
bridged the political gap in our studies by 77% on average. In some
cases, the political divide was even reversed—conservatives liked
past-focused environmental appeals more than liberals did (study 1)
and allocated more money than liberals to past-focused environ-
mental charities (study 6). One limitation of this research is that we
relied on relatively small samples drawn from Amazon MTurk. We
welcome research to replicate these findings in a large-scale, na-
tionally representative sample. Doing so also would be helpful in
determining how large an impact a temporal-framing intervention
could have in a naturalistic setting.
Our findings align with a strong tradition in social psychology and
social cognition demonstrating the influence of framing on attitudes.
Even subtle differences in framing can mean the difference between
acceptance and rejection of a message (28). Messages that are sup-
ported by scientific evidence are especially effective when acceptance
of the message also means that one’s personal values can be upheld
(29, 30). Messages concerning global warming and climate change are
no exception: They need to be tailored with great care (31–33). In-
deed, over the last several years the message of climate change has
been framed in many ways—from fatalistic predictions about the
future to calls for social progress (33). However, our research suggests
that these messages will not be as effective in bridging the political
divide if they continue to make future-focused comparisons. Para-
doxically, it is the past that may be critical in saving the future.
Fig. 5. Study 6. Conservatives donate more to the past-focused charity than
to the future-focused charity, while the opposite is the case for liberals. Error
bars represent SEs.
www.pnas.org/cgi/doi/10.1073/pnas.1610834113 Baldwin and Lammers
ACKNOWLEDGMENTS. We thank the members of the Social Cognition Cen-
ter Cologne and in particular the Mussweiler laboratory for feedback on this
research. This research was funded by a Junior Start-Up Grant awarded by
the Center for Social and Economic Behavior, University of Cologne.
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