How to Inoculate the Public Against Misinformation About Climate Change

Our article “How to Inoculate the Public Against Misinformation About Climate Change” was published January 23rd, 2017, in Global Challenges: Climate Change.

Prior studies have found widespread public misunderstanding about the scientific consensus that human-caused global warming is happening. A series of experiments have also found that simply informing people of the fact that 97% of climate scientists are convinced human-caused global warming is happening, significantly increases public understanding of the consensus. In turn, the increase in public understanding of the scientific consensus is associated with smaller, but potentially important increases in respondents’ own conviction that global warming is happening, human-caused, and a worrisome threat that requires action.

However, the basic fact of the scientific consensus has long been challenged by opponents of climate action, who have attempted to sow doubt among the public.

The study tested whether preemptive “inoculation messages” can protect the beneficial effects of communicating the scientific consensus against real-world misinformation. We found that inoculation messages can protect much of the beneficial effect of the scientific consensus message, across politically diverse members of the public. Just as a small dose of vaccine activates the body’s immune system to protect against an infectious disease, so message inoculation can help protect the mind against the effects of disinformation.

In this study, we divided participants into 6 groups. Group 1 was a control group. Group 2 received the scientific consensus message, which increased their own estimate of the consensus by about 20 percentage points, consistent with prior studies. Group 3 received a classic disinformation message (the Oregon Petition) arguing that over 31,000 American scientists have signed a petition claiming that “there is no convincing scientific evidence of human-caused global warming.” This reduced participant’s estimates of the consensus by about 9 percentage points. Group 4 received both messages, which canceled each other out.

Groups 5 and 6, however, first received the consensus message and then either a shorter or longer inoculation message before receiving the disinformation message. The short inoculation warned that “some politically motivated groups use misleading tactics to try to convince the public that there is a lot of disagreement among scientists.” The longer inoculation added details about the Oregon Petition specifically (e.g., explaining that some of the signatories are fraudulent, including Charles Darwin and members of the Spice Girls, and that fewer than 1% of the signatories have a background in atmospheric/climate science). As predicted, the inoculation messages protected much (up to two thirds) of the positive effect of the consensus message.