Based on studies, there are deficiencies and limitations in previous related research which applied the HBM. In distinguishing this research from other relevant consumer research on functional foods, this research will use a different approach and will fill the gaps in previous research.
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Several numbers of the limitations of the HBM model in the context of the proposed study have been identified based on literature review. These are identified in the material that follows.
The first limitation concerns the limited context of current literature using the HBM. None of the previous studies apply the HBM in the context of comparative analysis of consumers towards different types of functional foods. Examples of previous studies using HBM such as Gutierrez and Long (2011) focused on diabetes, Asci and Sahin (2011) focused on breast health, and Kim et al., (2012) focused on nutrients belief. Since the present study focuses on the factors to influence the intention of consumption of functional foods, the foods that being promoted as healthier products, therefore it is suggested that the properties of the HBM model are suitable to predict consumer behaviour of different types of functional foods.
The second limitation is that most HBM-based previous research has incorporated only selected components of the original HBM and has not tested the complete model with its four original constructs simultaneously. For example, Vassallo et al., (2009) used only 2 out of 4 original HBM constructs in their study. The original construct of Perceived Benefits and Perceived Barriers was omitted without any justification. As Vassallo et al., (2009) claimed the study was applying HBM as its main framework, they should assess the validity and reliability of all four original HBM constructs prior to omitting two of the original constructs.
In a related development of studies which utilised the Health Belief Model (HBM) in the context of food behaviour, Trenkner et al., (1990) developed a theoretical framework which was based from the HBM to predict individual behaviour towards healthy eating to prevent cancer. It utilised only two original constructs of the HBM, which are Perceived Benefits and Perceived Barrier. Schafer et al. (1993) examined attitudes towards food safety using two original HBM constructs (i.e. Perceived Susceptibility, Perceived Severity). Yazdanpanah et al., (2015) developed a framework with four determinants which only two of its constructs assessed the original HBM constructs (Perceived Benefits and Perceived
Barriers) in the study of consumer behaviour towards organic foods. Hanson et al., (2015) only assessed three original constructs of HBM (Perceived Susceptibility, Perceived Severity, and Cue to Action) in the study of food handling behaviour. In a recent study, Perceived Benefits and Perceived Severity are only the original HBM constructs among others in the framework developed by Fathi et al., (2017) to study the consumption of junk foods. Such studies related to food that utilised HBM as their frameworks have an obvious gap when the
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researchers were not fully utilised all original constructs of HBM (i.e. Perceived
Susceptibility, Perceived Severity, Perceived Benefits, Perceived Barriers, Cue to Action). The third limitation concerns the limited scope of the constructs in the HBM. The emphasis to be highlighted includes reviewing the limitations of the original HBM and to propose an extended model that includes other constructs to improve the model. The original HBM only explores the four constructs of Perceived Susceptibility, Perceived Severity, Perceived Benefits, and Perceived Barriers (Rosenstock 1974). These constructs should be extended further, particularly to explore consumer behaviour towards different types of functional foods. For example, in order to capture the influence of different individual perceptions on the consumption of functional foods, and as discussed in Chapter 3, an additional construct of Self-Identity is to be included.
The fourth limitation concerns the nature of the dependent variable in the HBM. The HBM emphasises the relationship between HBM constructs and the dependent variable of Taking Recommended Preventive Health Action. The deficiency of the current approach is that it does not focus on consumer purchase intentions. Much of the current literature on the behavioural change implications of HBM suggests that HBM has properties that can translate into improving consumer behaviour to engage with healthier health behaviour. Nevertheless, the original dependent variable in the original HBM is still lacking as it does not have its own scales of measurement model to measure the behaviour of Taking Recommended Preventive Health Action” per se specifically. Previous studies utilised the HBM model in various contexts translated dependent variable in various forms according to the context of their research. For example, Ghanbari et al., (2014) presented the measurement of the dependent variable of the HBM as “the hand hygiene behaviour”.
In a related development, many of recent studies have utilised Intention as the dependent variable of consumer behaviour studies which explained earlier in Section 2.9. Among them include Hung et al., (2016), Kraus (2015a, b), Lu (2015), Irene and Spiller (2014), Van Wezemael et al., (2014), Lau et al., (2012), Hirogaki (2013), Chung et al.,
(2011), Labrecque et al., (2006), Hur and Jang (2015), Siro et al., (2008), Tobin et al., (2014). Therefore, it is suggested to be more appropriate if the model could predict consumers’
purchase intentions. It can be realised by replacing the HBM original dependent variable of Taking Recommended Preventive Health Action” to Intention as to make it more reliable and practical to be measured. In supporting this argument, existing scales of the measurement
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models of Intention of TPB in relevant studies can be replicated and modified accordingly. The effort in the modification of the original dependent variable in the HBM fulfils the existing gap and compatibly in the context of this study. Details for the dependent construct ‘Intention’ are discussed in Chapter 4 (The Conceptual Framework).
2.12 Chapter Summary
In summary, Chapter 2 in this literature review has provided insights and ideas on how the association between functional food and consumer behaviour. It also justifies the selection of theory to be used in this study, which based on psychology behaviour. The discussion of literature review continues with Chapter 3 for more interesting recent facts and figures. It will support and justify the reason of the conceptual selection with focus products to be assessed in this study.
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