Irene Thijssen

A product’s attractiveness is an important driver in food preferences, choices and consumption behaviour. Inherently, healthier food products (i.e., ‘light’, sugar- or fat-reduced) are often perceived as less attractive, mainly in terms of liking, macronutrients, and sensory properties. Thus, healthier products are at a ‘sensory disadvantage’ and may be seen as less rewarding compared to their regular counterparts. Making healthier products more attractive could bridge this gap to help overcome the perceived or inferred shortcomings of healthier products. Extrinsic information such as package colour can influence our product expectations and perception, and could be an effective way to enhance the attractiveness of healthier products.

The research described in this thesis explored the effectiveness of package design and package colour aspects to make healthier food products more attractive. The influence of package design and colour aspects on product expectations, associations and evaluation upon tasting, both initially as over repeated encounters, were studied using questionnaires, sensory tests and implicit association tests (IATs). The underlying brain mechanisms and cognitive processes underlying these effects were investigated using functional Magnetic Resonance Imaging (fMRI).

Chapter 2 investigated the effects of several package colour aspects (hue, brightness and saturation) on perceived healthiness, attractiveness of food products, and sensory expectations based on the package alone, as well as product evaluation upon tasting in presence of the package. Implicit Association Tests (IATs) were used to measure the strength of associations between package colour aspects and perceived attractiveness and healthiness of the products. The results showed that the effects of package colour aspects were stronger for product expectations than for evaluations upon tasting. Packaging healthier products in warmer, saturated and less bright coloured packages (more similar to regular products) explicitly enhanced sensory expectations and evaluations, and implicitly improved attractiveness.

In Chapter 3 the neural (brain activity patterns) and cognitive mechanisms, and the extent to which package colour aspects influence product perception were further investigated using fMRI. Packages with colour aspects representing healthier product packages (i.e., high brightness, low saturation) and regular product packages (i.e., low brightness, high saturation) were used as stimuli and brain responses where measured while viewing the packages, with and without simultaneously tasting two products (healthier and regular dairy drink). Results showed that package colour and taste properties modulate neural correlates. The influence of package colour aspects was predominantly elicited via top-down systems in brain regions related to reward representation and inhibitory control.

Across several experiments (Chapter 2, 5), implicit association tests (IATs) were employed to investigate subconscious attitudes with respect to healthiness and attractiveness. In Chapter 4 results from all IATs were consolidated to determine the robustness of implicit associations between package colour aspects and concepts of healthiness and attractiveness. Results consistently showed that less vibrantly coloured packages and ‘cool’ coloured packages were implicitly more strongly associated with healthiness compared to vibrantly coloured packages and ‘warm’ coloured packages. Similarly, vibrantly coloured packages and ‘warm’ coloured packages were shown to be more strongly associated with attractiveness compared to less vibrantly coloured packages and ‘cool’ coloured packages.

In Chapter 5, an experiment is described with two biscuit packages signalling either healthiness or tastiness of the biscuits. These packages were exclusively designed and produced for this study. The aim was to determine the influence of a multitude of package cues, including package colour, on product expectations as well as repeated (long-term) evaluation in a more realistic at-home setting. Implicit (IATs) as well as explicit (questionnaires) measurement tools were used and results showed that package designs mainly influenced product expectations. Product perception upon tasting was predominantly shaped by the intrinsic (flavour) properties of the biscuit itself. Implicitly, changes in associations between package design and perceived healthiness and attractiveness over time were seen. The direction of change depended on the package design thereby indicating a product-package interaction.

Lastly, in Chapter 6, the general discussion, the main findings and conclusions of this PhD thesis were described. Results showed that package design and colour aspects predominantly influence product expectations, and to a lesser extent product evaluation upon consumption. These influences are assumed to be the result of top-down processing in brain regions involved in reward and inhibitory control. On an implicit level, ‘warm’ and vibrantly coloured packages were clearly more associated with attractiveness (and unhealthiness) than ‘cool’ and less vibrantly coloured packages, and these associations were dynamic over time, where the directionality depended on the interaction between product and package.

Overall, we demonstrated the ability of package design and colour aspects to influence a product’s attractiveness, thereby potentially making healthier products more attractive to the consumer. The longevity and generalisability of these influences is however less clear and needs further investigation. Combining methods that capture conscious as well as less conscious aspects of food related behaviours, is recommended to better predict food related behaviour in real-life situations.