The consumption of meat and meat products has been cited as the most critical area to be addressed if we are to meet a sustainable future diet, regarding the impact on climate change and health. The numerous sustainability concerns that have been raised have stimulated calls to reduce the quantity of meat people in general eat, and have created an on-going global debate among policymakers, academics and practitioners. This research makes use of the Integrative Model of Behavioural Prediction (IMBP) in order to isolate the key determinants of what drives the intentions of middle to upper-income South Africans to engage in a meat-reduced diet (MRD). A two-phase methodology was utilised, by firstly conducting an elicitation study to identify the salient beliefs present in the population, and secondly by conducting a population survey to quantify the cognitive foundation of this behaviour. The empirical results showed that the areas of cognition which most strongly predict whether one intends to engage in an MRD were instrumental attitude, experiential attitude and injunctive norms. This study makes three primary contributions. Firstly, a theoretical contribution, through providing insight into how behavioural themes and beliefs materialise into changes in meat-consumption. Secondly, marketing practitioners can benefit from the insight offered by IMBP, which is valuable as it helps to identify what behavioural shift is required to promote MRDs. Lastly, this study contributes to the methodology utilised when applying the IMBP by applying the model to dietary behaviour, which has received comparatively less attention in the past.

Understanding and predicting human behaviour has been of particular interest to marketers for many years. The predominant approach to predicting behaviour has relied on attitude-based models; in particular, Ajzen's (1985) theory of planned behaviour is considered the most sophisticated methodology available to researchers for behavioural prediction. However, despite much study and refinement, the predictive ability of such models remains relatively poor. Rather than continuing to rely on cognitive models, it is time to consider alternative approaches to predicting behaviour. Labaw (1980) offers one such alternative approach based on information about respondents' environment, knowledge and past behaviour. However, unlike Ajzen's theory of planned behaviour, Labaw's approach to predicting behaviour has not been widely operationalised or tested. Therefore, it is not known whether her approach, using questions that, at least theoretically, have verifiable answers, has greater predictive ability than Ajzen's theory of planned behaviour, based on attitudinal questions. This study compared the predictive ability of Ajzen's attitudinal-based theory of planned behaviour with Labaw's behavioural approach, in the context of blood donation behaviour. In absolute terms, the predictive ability of the two approaches was equivalent; however, Labaw's approach was superior to the theory of planned behaviour from a survey research perspective. Thus, Labaw's approach presents a feasible alternative to attitudinal-based approaches to predicting behaviour. This study also found that behavioural intention to donate blood was a poor predictor of actual (self-reported) donation behaviour. This finding is important given the widely-accepted assumption that the best prediction of behaviour is provided by measures of behavioural intention. In addition, the study suggests that researchers need to carefully consider the time interval selected to test the predictive ability of a model if the results are to have any practical relevance. Variables that help explain the decision to donate blood were also identified. These findings offer blood collection agencies guidance with formulating specific strategies to address blood donor shortages. However, accurately predicting who is most likely to donate blood remains problematic, and further research is needed to extend the results reported in this study.

Cette thèse a pour objet d’étude la prédiction de l’utilisation d’une technologie encore inconnue des utilisateurs ; c’est-à-dire une technologie que ces derniers n’ont pas encore eu l’occasion de mettre en pratique et de facto pour laquelle ils n’ont pas de représentation. Trois objectifs sont poursuivis dans ce travail. Le premier est la construction d’un modèle prédictif de l’intention comportementale d’utiliser les systèmes de transports intelligents coopératifs inconnus en convoquant les deux cadres théoriques que sont l’acceptabilité des technologies (e.g., Venkatesh et Bala, 2008) et la prédiction comportementale (Ajzen, 1991 ; Ajzen et Fishbein, 1973). L’un, focalisé sur le jugement de l’individu sur l’objet, implique la connaissance de cet objet. L’expérience antérieure et les attitudes envers des objets génériques et spécifiques connus proches de l’objet dont on souhaite prédire l’utilisation ont composé la première partie (A) du modèle. L’autre, focalisé sur le jugement de l’individu sur l’utilisation de l’objet autorise les individus à se projeter quant à la valeur attendue de l’utilisation et aux attentes sur les conséquences de cette utilisation (i.e., les origines des attitudes), à la pression de leurs proches et au contrôle qu’ils perçoivent de l’utilisation de la technologie inconnue. Ces déterminants ont composé la seconde partie (B) du modèle. Le deuxième objectif vise à tester, au cours d’une première étude, la structure factorielle de deux questionnaires relatifs à ces deux cadres théoriques A et B. Les résultats nous ont conduits à retenir un modèle en sept facteurs afin de le tester au cours d’une deuxième étude. Les résultats ont montré que l’expérience antérieure avec des objets génériques connus prédisait indirectement l’intention d’utiliser l’objet inconnu via une médiation par les attitudes envers les objets génériques, l’expérience antérieure avec les objets spécifiques et la valeur / attentes à l’égard de l’utilisation de l’objet inconnu. Les résultats ont également montré l’influence indirecte de la norme subjective et du contrôle anticipé de l’utilisation de l’objet sur l’intention via une médiation, là encore, par la valeur / attentes à l’égard de l’utilisation de l’objet inconnu. Le troisième objectif vise à relier l’intention d’utilisation avec l’utilisation réelle des systèmes de transports intelligents coopératifs en situation de conduite automobile. Ces derniers résultats, bien que ténus, ont montré que l’on pouvait réaliser cette prédiction lorsque les situations de conduite étaient adaptées à l’utilisation de la technologie (e.g., Theeuwes, 1993).Mots-clés: prédiction comportementale; acceptabilité des technologies; attitudes; intention comportementale ; comportement ; activité de conduite automobile. / This thesis focuses on the prediction of the use of an unknown technology; that is to say the users did not have yet the opportunity to practice this technology, so they still have no representation of this technology. Three objectives are pursued in this work. The first one is the construction of a predictive model of the behavioural intention to use the unknown cooperative intelligent transport systems by convening the two theoretical frameworks which are the acceptability of the technologies (e.g., Venkatesh & Bala, 2008) and the behavioural prediction (Ajzen, 1991; Ajzen & Fishbein, 1973). One of them, focused on the judgment of individuals onto the object, implies the knowledge of this object. Hence the first part (A) of the model is based on past behaviours and attitudes towards generic and specific known objects close to the one that we want to predict the use. The other one is focused on the judgment of individuals onto the use of the object. This enables individuals to project themselves regarding the expected behaviour value and the expectations of the results of using it (i.e., the attitudes’ determinants), and both the subjective norm and the perceived behavioural control of the use of this unknown technology. These determinants form the second part (B) of the model. The second objective aims at testing, in a first study, the factor structure of the two questionnaires A and B. The results led us to retain a model based on seven factors in order to test it in a second study. The results showed that past behaviours with known generic objects indirectly predicted the intention to use the unknown object via a mediation through attitudes towards generic objects, past behaviours with specific objects, expected behaviour value and expectations of the results of the use of the unknown technology. Also, the results showed an indirect influence of the subjective norm and the perceived behavioural control on the intention to use the unknown object via a mediation by the value / expectations regarding the use of the unknown object. The third objective aims at linking the intention with the actual use of cooperative intelligent transport systems in driving situations. These results, although tenuous, have shown that this prediction could be made when the driving situations were consistant with the use of the technology (Theeuwes, 1993).Keywords: behavioural prediction; technology acceptance; attitudes; behavioural intention; behaviour; activity of driving.