Contents lists available at ScienceDirect Food Quality and Preference journal homepage: www.elsevier.com/locate/foodqual Short Communication The influence of illuminance level on perception and willingness to buy during the tasting of sweetened natural yoghurt Rubén Rebollar a, ⁎ , Iván Lidón a , Rafael Guzmán b , Ignacio Gil a , Javier Martín c,d a Departamento de Ingeniería de Diseño y Fabricación, Escuela de Ingeniería y Arquitectura, Universidad de Zaragoza, c/ María de Luna 3, C.P. 50018 Zaragoza, Spain b Departamento de Expresión Gráfica, Diseño y Proyectos, Escuela de Ingenierías, Universidad de Málaga, c/ Doctor Ortiz Ramos, s/n, C.P. 29071 Málaga, Spain c Departamento de Estadística, Universidad de Salamanca, c/ Espejo 2, C.P. 37007 Salamanca, Spain d Bioestatistics Unit-IBSAL, Instituto de Investigación Biomédica de Salamanca, Paseo de San Vicente 58-182, 37007 Salamanca, Spain ARTICLE INFO Keywords: Food perception Illumination Illuminance level Gender differences ABSTRACT This paper analyses the influence of the illuminance level of a light source on how consumers evaluated certain attributes of sweetened natural yoghurt and on their willingness to buy during product tasting. It also seeks to identify whether or not gender differences played a role in these evaluations. To do this, we conducted an independent within-subjects experiment (N = 69) where illuminance level (low versus high) was studied. Participants had to assess one sensory attribute (‘Sweet’), three non-sensory attributes (‘Healthy’, ‘Natural’ and ‘Quality’) and willingness to buy for sweetened natural yoghurt. The results show that illuminance level influences the evaluation of some attributes and that there are discernible gender differences. In general, the consumers perceived the yoghurt to be healthier under low illuminance conditions and women perceived the yoghurt to be sweeter under high illuminance. Although the effects identified were not numerous, these findings suggest that illuminance level can influence consumers’ tasting experiences as well as their willingness to buy. The limitations of this research are discussed as well as their possible practical implications. 1. Introduction Among the environmental factors that affect food consumption, illumination has frequently attracted the interest of researchers. One of the properties of illumination that has been analysed with respect to how consumers perceive food is illuminance level. Some evidence suggests that illuminance level influences the eating behaviours (Wansink, 2004; Wansink & van Ittersum, 2012) and physiological processes of consumers (Jin, Katsuura, Iwanaga, Shimomura, & Inoie, 2007; Katsuura, Jin, Baba, Shimomura, & Iwanaga, 2005). A high illuminance level shortens the amount of time people stay in a restaurant (Sommer, 1969), while a low level creates favourable conditions for people to stay longer and enjoy their food more and discourages consumption (Ross, 2014; Wansink, 2004; Wansink & van Ittersum, 2012). One possible explanation for this is that low illumi- nance conditions may promote behavioural disinhibition (Kasof, 2002). Two seminal studies in this field, Gregson (1964) and Wilson and Gregson (1967), explored the influence of illuminance level on the way consumers perceive the sensory attributes of a particular food. These experiments found that modulating the illuminance level of a light source can affect the consumer’s capacity to discern the acidic flavour of a drink. In another more recent study, Gal, Wheeler, and Shiv (2007) found that illuminance level affects both coffee flavour perception and coffee consumption. Interestingly, they discovered that habitual con- sumers of strong coffee drank more under bright lighting whereas habitual consumers of weak coffee drank more under dim lighting. Only a few studies analyse the relationship between illuminance level and the evaluation of a product’s sensory attributes. In one such study, Katsuura et al. (2005) analysed the influence of illuminance level on the taste threshold of the four basic tastes in Japanese and Chinese subjects. It was found, in both cases, that sensitivity to sweet and bitter tastes was lower under lower illuminance conditions. Moreover, although some studies have demonstrated that other environmental factors can affect willingness to buy (Spence, Puccinelli, Grewal, & Roggeveen, 2014), there are no studies that examine the relationship between illuminance level and willingness to buy. Therefore, considering the scope of the literature published to date, it seemed pertinent to study the way in which the illuminance level of a light source can affect how a food is perceived. For this experiment, sweetened natural yoghurt was chosen because it is a product that is well-known to a large portion of the population yet not frequently consumed, meaning it would be difficult for the user to have a familiar http://dx.doi.org/10.1016/j.foodqual.2017.05.007 Received 29 August 2016; Received in revised form 15 May 2017; Accepted 15 May 2017 ⁎ Corresponding author. E-mail address: rebollar@unizar.es (R. Rebollar). Food Quality and Preference xxx (xxxx) xxx–xxx 0950-3293/ © 2017 Elsevier Ltd. All rights reserved. Please cite this article as: Rebollar, R., Food Quality and Preference (2017), http://dx.doi.org/10.1016/j.foodqual.2017.05.007