Thursday, 12 April 2012

Dead plants encourage belief in global warming

In 2006, the Conservative party in the UK unveiled its new logo - a scribbled sketch of a healthy-looking oak tree. The image was intended in part to communicate the party's renewed dedication to environmental causes. A new study by French psychologist Nicolas Guéguen suggests that if the Conservatives want to help change people's attitudes towards the environment, they should consider adapting their logo to one of a dying tree. Why? Guéguen has shown that the presence of dead plants strengthens people's beliefs in global warming.

In the first of two studies, Guéguen had 60 participants fill out a questionnaire about current affairs, including four questions about global warming, such as: "It seems to me that the temperature is warmer now than in previous years." Crucially, half the participants filled out the questionnaire in a room in the presence of a 150cm tall ficus tree with luscious green leaves; the other participants in a room in the company of a dead ficus tree. The finding: participants in the dead tree condition expressed far stronger beliefs in global warming than the participants in the other group, whilst their answers to the remaining questions were no different.

In a follow-up study, Guéguen introduced a no-tree condition, to make sure that it's not the case that the presence of a healthy plant weakens beliefs about global warming. He also featured a condition with three dead or healthy plants - a ficus, a bonsai and a dracaena. The presence of healthy plants made no difference to global warming beliefs versus the no-plant control condition. Once again, however, the presence of a dead plant strengthened beliefs in global warming, and more dead plants meant even stronger such beliefs. No students in either study guessed the aims of the research.

Guéguen speculated that the sight of dead plants probably triggered in participants' minds concepts associated with global warming, such as heat and drought, without them being consciously aware of this effect. The new findings chime with earlier research showing how incidental circumstances influence people's belief in climate change - for example, people are more likely to say they believe in climate change on warmer days. A weakness of the study is that there's no mention of whether the female experimenter who dealt with the participants was blind to the aims of the research - might she have affected their results through her own behaviour?

Notwithstanding that issue, the study has obvious practical implications. Guéguen suggested that in public toilets, for example, the presence of plants without foliage could encourage less water consumption when washing one's hands (though that might harm hygiene initiatives!). More generally, Guéguen advised, "people who want to heighten public awareness on the topic [of global warming] could profitably use photographs or videos of dead plants, or plants without foliage, thus increasing the effectiveness of public awareness campaigns."


Guéguen, N. (2012). Dead indoor plants strengthen belief in global warming. Journal of Environmental Psychology, 32 (2), 173-177 DOI: 10.1016/j.jenvp.2011.12.002

Post written by Christian Jarrett for the BPS Research Digest.


Martin g said...

Is that the same professor Guéguen who found that a fictitious mathematics tutor called 'Mr. Py' received more enquiries for work than did 'Mr. Le Gal' ?

And that 'Women exposed to flowers relative to women not exposed more frequently accepted a courtship request.'?

And that waitresses who wear makeup get more tips?

Alis said...

It's easy to poke fun at this kind of research with the old chestnut that 'psychology research just tells us what everybody already knows' (except, of course when it doesn't...) but a case could persuasively be made for people in the healthy tree condition being reminded of what they might lose through global warming and, therefore, give stronger assent to statements about its existence.

By the way, I'm a daily reader but a rare commenter - thanks for the blog Christian, it's consistently fascinating.

David Johnson said...

Yeah, global warming is discussed a lot. I do not believe in global warming, however, the land has been damaged since it was first created. Christian, I think that plants also die, new ones come up.

But finally this is not a good land any more.

B Glummy said...

Nice piece of research. Would be interesting to see a baseline quantification of fear of global warming to see if there was an interaction between this and the presence of plants. Does the prescence of dead trees/plants have a greater effect on the beliefs of those that have prexisting fears of global warming than those that don't?

Brian B. said...

Yes, this might seem like one of those "Duh!" studies that needn't be conducted because it's so much "common sense." However, I find some value in highlighting how incidental circumstances influence perspective and decision-making -- keeping this case in mind, for example, survey-takers would be wise to avoid "man on the street" interviews in the middle of a luscious, green park on a breezy day. It's too easy to forget all the many random variables at play.

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