An attitude is defined here as a subjective evaluation of a behaviour

An attitude is defined here as a subjective evaluation of a behaviour, which disposes a person
to behave in a certain way towards it (see Eagly & Chaiken, 1993; Gärling et al., 1998). A
crucial step in the history of attitude theory has been the development of the Theory of
Reasoned Action (TRA) and its successor, the Theory of Planned Behaviour (TPB) (Armitage
& Conner, 2001). Both theories are based on the idea that behaviours depend jointly on
motivation (intention) and ability (behavioural control) (Ajzen, 1987; 1991). However,
empirically, the TRA operationalization (Fishbein & Ajzen, 1975) states that intention
intermediates between behaviour and the attitude towards the behaviour. Intention depends
not only on attitudes, but also on subjective norms or the perceived social pressure exerted by
important others, such as parents and good friends, to perform or not to perform a behaviour.
The TPB (Ajzen, 1991) extended the TRA by including two behavioural control
variables. Perceived behavioural control stands for the confidence an individual has to
undertake a particular behaviour in a particular situation. It is assumed to have a direct impact
on intention and behaviour (Ajzen, 1991). Actual behaviour control, which refers to the
availability of requisite opportunities and resources such as time, money, and the cooperation
of others, has a direct impact on behaviour. Because this construct is often difficult to
measure, perceived behavioural control is usually used as a proxy for actual behavioural
control (Eagly & Chaiken, 1993). It is often assumed that perceived and actual behavioural
control are correlated (Gärling et al., 1998). However, little attention has been given in
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empirical research to the operationalization of external factors that could act as constraints on
behaviour.
In the course of time, several researchers have sought to extend the TPB by
introducing new predictors of intentions and, in turn, behaviour (Verplanken et al., 1997, for
example). One extension is the incorporation of habit. A habit is a learned act that becomes an
automatic response to a situation and can be functional in obtaining certain goals or end-states
(Verplanken et al., 1997). Another important extension is the addition of goals. These can
vary from concrete goals, such as buying clothes, to higher level ends, such as a feeling of
wellbeing acquired by wearing new clothes. Goals are considered in the Extended Model of
Goal-directed Behaviour (EMGB) (Perugini & Conner, 2000), an advanced alternative to the
TPB, in which habits are also taken into account (through the concept of past behaviour). The
EMGB extends the Model of Goal-directed Behaviour (MGB) by adding goal desirability (the
strength of an action’s end state) and goal feasibility (the ease or difficulty of reaching the end
state) (Perugini ; Conner, 2000).
A crucial construct in the EMGB is behavioural desire, defined by Perugini and Conner
(2000, 706) as: “…the motivational state of mind wherein appraisals and reasons to act are
transformed into a motivation to do so.” Behavioural desire is treated as the most proximal
antecedent of intention. In the EMGB, a wider definition of intention is used, namely volition
(Perugini ; Conner; 2000), which constitutes a further extension of the TPB. This concept
takes the engagement in plans to reach a goal into account together with the effort needed to
enact the behaviour.
This short overview of attitude theories brings us to a simplified version of the EMGB
which could be used for choices in shopping modes (see Figure 1). As mentioned earlier,
actual behavioural control has been considered theoretically, but has not often been
operationalized in empirical research. Thus, a conceptualization of the constraints within
which intentions and behaviour occur has largely been omitted in attitude theory.
Nevertheless, constraints could play an important part in an individual’s choice process
(Hägerstrand, 1970; Desbarats, 1983). We therefore hypothesised that external variables such
as sociodemographics and personality traits have an impact on the antecedents of behaviour
such as volition, subjective norms, perceived behavioural control, and past behaviour.