T HEORY OF PLANNED BEHAVIOUR :

Theory of Planned Behaviour (TPB) (I Ajzen 2005) is the most applied social-psychological model that utilized for consumer intention and behaviour research. It received both successful employing and criticizing from a variety of published papers. According to Armitage and Conner (2001, 471) report on broad meta-analytic, the TPB predictors account for 27% and 39% variance of behaviour and intention respectively. TPB is extended from Theory of Reasoned Action (TRA) which designed by Ajzen and Fishbein to examine the volitional behaviour and related to causal antecedents’ intentions to perform behaviour (I Ajzen 2005). A variety of research that applied TPB evidence that behavioural intentions are good predictor of respective behaviours, but in fact it does not provide many information about the causes of the behaviour (I Ajzen 2005). In the TPB, the roots of the behavioural intention and actual behaviour are theorized as beliefs that are discussed below.

The central focus of TPB is that an individual’s intents to perform a given behaviour (George 2004, 199), hence, “A person’s intention to perform (or not to perform) a behaviour is the most important immediate determinant of that action” (I Ajzen 2005). Ajzen (2005, 117) explains that human being behave in a sensible manner, he or she implicitly or explicitly considers the available information to make judgments for different actions. Acting as the motive of behaviour intentions of actual behaviour is influenced by three determinants: attitude toward behaviour, subjective norms and perceived behavioural control (Song and Zahedi 2005, 1220;

I Ajzen 2005, 117–26). Before that, the predictor “attitudes” has not been considered as a predictor of behaviour until social psychologists develop integrated models of behaviour with additional determinants (e.g. social norms, or intentions) (Armitage and Conner 2001, 471).

The determinants can be shortly explained as below:

• Attitudes toward the behaviour (attitude) stand for personal attitude of the individual’s positive or negative evaluation to perform the behaviour of interest.

• Subjective norms (SN) are personal perception of social pressure to perform (or not perform) the behaviour under consideration.

• Perceived behavioural control (PBC) is the sense of self-efficacy or ability to perform the behaviour of interest.

Being the most applied psychological theory on online consumer behaviour (I Ajzen 2005;

Armitage and Conner 2001, 471; Cheung, Chan, and Limayem 2005, 4), TPB is widely utilized to test consumers’ intentions and actual behaviour in Internet shopping. For instance, the theory is applied to research on willingness to buy grocery online (Hansen, Møller Jensen, and Stubbe Solgaard 2004), the influence of trustworthiness factors in intention toward online shopping behaviour (George 2004, 199). Besides, TPB is extended to examine specific case such as the influence of Facebook advertisings that visible on new feeds or wall posting to intention to purchase weight-lost product online (Raghupathi and Fogel 2013), or the online purchasing intention towards organic foods that associated with different lifestyle (A. R.-D. Liang 2014), or the importance of trust in Thai consumers’ perceptions toward green products (Nuttavuthisit and Thøgersen 2017).

According to TPB, personal beliefs provide the cognitive ground for behaviour, they are the reasons why people hold certain attitudes, subjective norms, PBC and why they conduct the behaviour in question (I Ajzen 2005, 137). Personal beliefs are classified as behavioural beliefs, normative beliefs, and control beliefs supporting the three TPB antecedents (Figure 2).

Attitudes toward behaviour are functioned by behavioural beliefs that relates to predict outcomes, or other possible attributes such as the cost which properly occurs when behaviour is conducted. Subjective norms are influenced under the vital normative beliefs that closely related to the influences of “general social pressures” that come from certain individuals or groups who given the motivation or discourage the behaviour performance. PBC are functioned by the control beliefs related to specific factors of power that causing the supports or preventions of the performance (Armitage and Conner 2001, 474; I Ajzen 2005, 137).

Each of the determinants of TPB has different influences on behavioural intention and actual behaviour depends on existing relevance beliefs of the individuals. For instance, Armitage and Conner (2001, 478) determine that subjective norms in TRA is considered the weakest predictors in different research and deliberately removed from some analysis. Indeed, the influences of both attitude and subjective norms on intention are varied, depends on the individual. It is because different individual has different social environment and cognitive beliefs that are possibly related to or influenced by different variables that connected to his or

her attitude or (/and) social norms. These variables can be age, gender, ethnicity, socio-economic status, education, nationality, religious affiliation, personality, mood, emotion, general attitudes and values, intelligence, group membership, past experiences, exposure to information, social support, coping skills, and so forth (I Ajzen 2005, 135). So that the effects of psychological incentives of TPB may have different research results depend on research context and measurement methods.

Although TPB creates the framework for investigating the psychology aspects of the human behaviour, it does not specify any particular beliefs that related to particular behaviour, hence different research needs to indicate the related beliefs (George 2004, 200). Armitage and Conner (2001, 475) suggest that TPB is adapted to predict the behaviours and intentions in a wide range of contexts.

Figure 2:Theory of Planned Behaviour and background factors (I Ajzen 2005, 135)

To conclude, the individual performance of particular behaviour is determined by that person intent to conduct the behaviour. That behaviour is more likely to conduct when the results are believed achievable (Armitage and Conner 2001, 472) which depends on individual positive or

negative evaluation of the behaviour (George 2004, 199). Predicting degree of TPB determinants can link to personal beliefs, expected outcomes, the consequences of the behaviour, or link to some other determinants such as cost of performing the behaviour (I Ajzen 2005, 123) therefore the utilization of those factors to figure out the individual’ judgment to perform the behaviour is important. With regards to the study context, food shopping via Internet is a “voluntary individual behaviour” that can be investigated by behavioural theories like TRA and TPB (Limayem, Khalifa, and Frini 2000, 423), as a result, the TPB incentives and other possible extended constructs are ideal for this paper’s structure.