Janet K. Swim, Penn State professor of psychology and her colleagues report that growing consumption and growing population are two significant contributors to human impact on the environment. Both substantially increase carbon dioxide levels in the atmosphere, the researchers report in a special issue of American Psychologist that focuses on how psychology contributes to understanding and addressing global climate change.

Engaging in one type of environmentally friendly behavior can predispose one to engage in similar behaviors, inhibit other behaviors, or even increase environmentally harmful behaviors.

—Janet Swim

Swim and her colleagues reported that peoples’ perceptions of how their behavior affects the environment influences how they act. If people do not believe that the choices they make will substantially improve the environment, then they are less likely to participate in activities like recycling, turning off lights when leaving a room or car pooling.

Some behaviors offset environmental gains. If a family buys a fuel-efficient vehicle but chooses to drive more miles than they previously did, there is no gain for the environment. Also, while the average US household size is decreasing, Americans are generally choosing to live in larger homes, counteracting the energy savings on heating and cooling that could be made in smaller spaces.

Decisions about environmental consumption and behaviors that use environmental resources are influenced by culture as well as an individual’s abilities and motivations, the researchers noted. Some cultural factors are structural. For example, as people began moving further away from city centers, cars became important for transportation. Other cultural factors, however, influence perceived needs and desires.

The types of cars people drive and how fast people drive influence how much gasoline is consumed. Peoples’ cars and speed are often both influenced by advertising and others’ purchasing and driving behaviors.

People adjust their explanations for behaviors in ways that allow them to maintain their consumer lifestyles. Carpool lanes decrease carbon dioxide emissions and lower costs of commuting. In one study on carpooler explanations for driving choices, the researchers noted that prior to the existence of carpool lanes commuters said carpooling was too expensive. After carpool lanes were available, commuters were surveyed again and reported that flexibility prevented them from carpooling.

Cultural and individual abilities and needs also influence contraceptive use. Population growth in India has in part been attributed to the importance placed on male children, creating a cultural need to have more children in order to increase the number of sons.

Individually people often consider the emotional value of children when determining how many children to have. However, in some circumstances people consider the environmental effects as well. For example, in Nepal if people felt that “environmental destruction had influenced their agricultural productivity [they] were more likely to use contraceptives,” the researchers said.

Also working on this research were Susan Clayton, professor and chair of environmental studies, College of Wooster, and George S. Howard, professor of psychology, University of Notre Dame.

Resources

• Swim, Janet K.; Clayton, Susan; Howard, George S.(2011) Human behavioral contributions to climate change: Psychological and contextual drivers. American Psychologist, Vol 66(4), May-Jun 2011, 251-264. doi: 10.1037/a0023472