A comprehensive model of the psychology of environmental behaviour—A meta-analysis

Highlights

• The most common environmental psychological action-theories can be combined.

• Intentions, habits and perceived control are direct predictors of behaviour.

• Personal norms add to explained variation in intentions.

• Personal norms have a mediated influence on behaviour.

• The linear norm-activation chain from value-belief-norm theory is not supported.

Abstract

To address global environmental challenges it is crucial to understand how humans make decisions about environmentally relevant behaviour, since a shift to alternative behaviours can make a relevant difference. This paper proposes a comprehensive model of determinants of individual environmentally relevant behaviour based on a combination of the most common theories in environmental psychology. The model is tested using a meta-analytical structural equation modelling approach based on a pool of 56 different data sets with a variety of target behaviours. The model is supported by the data. Intentions to act, perceived behavioural control and habits were identified as direct predictors of behaviour. Intentions are predicted by attitudes, personal and social norms, and perceived behavioural control. Personal norms are predicted by social norms, perceived behavioural control, awareness of consequences, ascription of responsibility, an ecological world view and self-transcendence values. Self-enhancement values have a negative impact on personal norms. Based on the model, interventions to change behaviour need not only to include attitude campaigns but also a focus on de-habitualizing behaviour, strengthening the social support and increasing self-efficacy by concrete information about how to act. Value based interventions have only an indirect effect.

Introduction

Humankind is facing a number of global environmental challenges, such as climate change, resource depletion, or biodiversity loss. To counter these challenges both international and interdisciplinary efforts have to be made. Undertakings such as trying to understand the key drivers and processes behind behaviour causing these challenges, predicting their development over time and eventually changing the system enough to mitigate negative outcomes are essential. Notwithstanding the important role of technological development and international and national policy making, the contribution of individual behaviour should not be underestimated. Hertwich (2005) argues that household behaviour is the strongest contributor to total energy use and carbon dioxide emissions in most developed countries, when direct energy consumption and indirect energy consumption embedded in consumed goods and services are taken into account. In an analysis of the carbon footprint of 73 nations Hertwich and Peters (2009) conclude that 72% of all carbon dioxide emissions worldwide are connected to household consumption with food, shelter and mobility as the most important subcategories. Tukker and Jansen (2006) confirm this conclusion and calculate that approximately 70% of all life-cycle impacts of products and services consumed by households fall into the categories of food, housing and transport.

Although individuals in households have varying degrees of freedom, Jungbluth et al. (2000) argue that they can have an important impact by changing their behaviour, in particular their food choices. The degree to which individual behavioural change can reduce the environmental impact depends on several aspects (Dietz et al., 2009): (a) the impact the behaviour has, (b) the number of people who perform the behaviour, and (c) the percentage of those people who are willing or able to change the behaviour, referred to as ‘plasticity’. Dietz et al. (2009) estimated the potential impact of changing a list of behaviours on reducing carbon dioxide emissions in the US and came to the conclusion that the implementation of 17 relatively simple changes in behaviour would reduce the household related carbon dioxide emissions by approximately 20%, taking into account plasticities of behaviours. Dietz et al. (2009) argue that implementing such changes would not reduce well-being considerably. It therefore becomes crucial to acknowledge and accept that individual behaviour both significantly contributes to global environmental challenges and that individual behavioural change has the potential to reduce this impact significantly. Identifying the determinants of human environmental behaviour is pivotal. If we would like to change people's behaviour we need to understand what determines their actions and decisions. What makes some people use a bike while others use a car? What makes some people invest in insulating their house while others do not? What makes some people eat beef and others become vegetarians?

Since the 1980s environmental psychology has made an important contribution to this debate by proposing and testing theories and models that aim to predict environmentally relevant behaviour and to identify entry points for interventions to change the respective behaviour. Jackson (2005) gives a very comprehensive summary of the models and approaches that environmental psychology has developed. However, different model schools developed in environmental psychology, which lead to a diversity of proposed models and a large variety of variables that are considered to have an impact on environmentally relevant behaviour. Both from a theoretical and a practical perspective it would be helpful to reduce the complexity of environmental psychological theory by integrating the most successful theories into a general theory which additionally includes assumptions about how the variables of the different models relate to each other across different model traditions. So far it is not entirely clear which of the model variables are central integrating variables, or which of those that are direct determinants of behaviour or those that have a mediated influence. Integrating the major models and theories into a comprehensive model that in turn could be used as a framework for identifying potentially relevant variables across behaviours and cultures is promising. It could potentially increase the impact that environmental psychology would have in the debate about mitigation of environmental problems. This is achievable by pointing out the variables that should be primary targets for interventions and additionally by elucidating which of the more distal variables may be used for achieving a change in variables proximal to behaviour. It would assist in identifying the key determinants of behaviour and indicating the barriers to behaviour change. However, this would require that such a model is sufficiently structurally robust to perform well, not only for specific behaviours of specific groups of people but also on a general level. Therefore, this paper proposes a comprehensive action determination model (CADM) of environmental behaviour and tests the model in a meta-analytical structural equation modelling approach (Viswesvaran and Ones, 1995) across a large variety of environmentally relevant behaviours.