for the issue than supporters of liberal parties
(22). Even as climate science data have accumulated and consensus of grave risk has grown in
the scientific community, concern about climate
change has decreased among those with a conservative worldview (23).
The striking difference in response to climate
change stems in part from motivated cognition.
Rather than neutrally receiving information, human brains privilege that which supports their
preexisting worldview. Given limited mental resources for processing the boundless information
available in the world, evolution favored cognitive
efficiency. New information is processed through
the filters of personal beliefs, first-hand experiences, and social identities. Ideas are dismissed
or assimilated on the basis of a quick but biased
heuristic of whether they line up with what is already perceived to be true. It is difficult to escape bias, even when exerting conscious mental
effort. Ironically, it appears that those with the
highest science literacy may exhibit more ideology-based bias than others, because their familiarity
with science makes them better equipped to
find supporting evidence for their preconceived
Psychological tools for
These and other psychological “dragons of inaction” (25) explain why humans are failing to
take sufficient action to address environmental
degradation. Social scientists are developing
psychologically informed strategies to overcome
barriers and encourage pro-environmental behavior (10, 26). Specific tools include framing
information about an issue such as climate
change to emphasize current and local impacts
(27), creating incentives that increase the short-term rewards of a sustainable action (28), and
encouraging social modeling to reset the perceived social norm around a pro-environmental
Devising behavior-change interventions is complex and time-consuming because the effectiveness of a particular tool varies widely depending
on what, and whose, behavior is at stake (29).
Each individual behavior comes with a unique
set of barriers and benefits, and each person approaches these with varying levels of motivation.
Despite increased attention from behavioral scientists, few resources exist to guide practitioners
about when and how to apply specific psychological tools (28, 29). One exception is community-based social marketing (CBSM) (30), a five-step
community-level approach that matches appropriate tools of change to the exact barriers, both
physical and psychological, that inhibit a specific sustainable action (28).
CBSM has been used to address sustainable
behavior in communities around the world and
remains a promising strategy for individual change.
Yet, given the scale and pace of continued environmental destruction, psychologists need to
move beyond targeting individuals’ private-sphere
choices and focus on how to foster collective action (Fig. 1).
Individuals and collective action
The power of the individual to mitigate environmental harm is severely constrained by physical
and social contexts, such as the industrial infrastructure for growing and transporting food, generating energy, and producing goods; the urban
structures built for living, working, and playing;
and the rules and policies of the many groups
and organizations to which people belong. Above
and beyond the ecological damage inflicted by
individuals’ personal behaviors is the damage
from the inefficient and wasteful industrial systems and processes through which individuals
meet their daily needs.
For example, one study estimated that just 90
businesses have generated 63% of the cumulative,
global greenhouse gas emissions (31). Even incremental improvements in systemic processes and
infrastructure will have much broader impacts
than will individual efforts (32, 33). Thus, it is
critical that efforts to overcome individuals’ barriers to change focus not only on motivating them
to behave sustainably in their personal sphere, but
also on inspiring them to participate in collective
efforts to change the larger systems and infrastructure (34). Recent research in political psychology has begun to provide important insights
for facilitating involvement in such systems-level
Unlike changing personal behaviors, transform-
ing systems requires individuals to participate
in public dialogue and activism in both informal
and formal social collectives. If they embrace
change at all, most people gravitate toward pri-
vate, individual behavior and avoid potentially
uncomfortable public advocacy and action (36).
Individual change is already challenging. It takes
even greater courage and perseverance to openly
question the dominant worldview that forms the
bedrock of cultural norms (Fig. 2).
Perceived social risks, such as fear of appearing biased or incompetent, fear of rejection, or
the belief that others disagree about the issue,
inhibit many from speaking out about critical
issues. People tend to underestimate how many
others share their opinion, which hampers willingness to be vocal (37). Emerging evidence suggests, however, that when individuals realize they
are not alone in their beliefs about a contentious
issue, they become willing to speak out. Specifically, self-censorship about anthropogenic climate
change decreases when people understand just
how many others acknowledge its reality and
are concerned about it (38).
Individual behaviors such as voting, contacting
elected representatives, and supporting issue-focused
organizations are essential to functional democ-racies. These acts ultimately affect local, national,
and even international policy. Evidence suggests
that political activism about conservation, like
many behaviors, requires the belief that political
action is necessary, influences others, and can
actually change environmental outcomes (36).
Emerging evidence points to several key ingredients that must be in place before individuals
enter into more public collective efforts on behalf
of the environment. Alignment with social identity is critical, and the deeper the identification,
the greater the individual’s commitment to the
success of the group. In addition, people only join
SCIENCE sciencemag.org 21 APRIL 2017 • VOL 356 ISSUE 6335 277
Changenorms • systems • stories •symbols
Runforpublicofce• create laws • organize•vote•protest
Shareideas•changeprocesses & procedures•createdurableproducts
S harematerialgoods•teach•persuade•supportothers•bealeade r
L e arn•donatemoney&time•walk•reduce•reus e
Private & personal
Fig. 1. An individual’s spheres of influence. Individual actions have the greatest effect when they
influence broader systems.