Cross-sectional illusions: what we have learned about the attitude-behaviour relationship and its policy implications

We describe and challenge long-standing assumptions in transport research about the direction and strength of the relationship between attitudes and behaviour. Economic and social science theories suggest a one-way effect from attitudes (interchangeably perceptions or motives) to behaviour. Drawing on a synthesis of empirical studies focused on car use and ownership, we show that this view is simplistic. Most research tests this relationship through cross-sectional data and reports medium to large effects from attitude to behaviour (behavioural intention). However, in modern (travel) behavioural modelling, emerging (longitudinal) panel models reveal that: (i) the attitude-behaviour relationship is bidirectional, (ii) the strength of the real effects is weaker than what is suggested by cross-sectional studies, (iii) attitudes are more a function of behaviours, not the other way around, and (iv) behaviours are more a function of past behaviours than of deliberate planning; contrary to the assumptions of the theory of planned behaviour. From a policy perspective, expecting to change (travel) behaviour solely by changing attitudes, often referred to as soft or pull measures, may be overly optimistic. We advise researchers to be cautious when using cross-sectional data to inform policy decisions. Directions for future research are also discussed.