New thesis: New methodologies in sensory and consumer research with preadolescents to guide product development of healthy, child-centered food

Martina Galler successfully defended her PhD thesis “New methodologies in sensory and consumer research with preadolescents to guide product development of healthy, child-centered food”

Date and place of defence: Digital/Ås, Norway on Friday December 17, 2021.

Institution: Nofima, Norway


In spite of the strong covid measures at the end of the year, Martina had her close family physically joining the event, while colleagues and friends supported her online and attended the excellent scientific discussion during the defence.



Associate Professor Monica Laureati, Università degli Studi di Milano, Italy

Associate Professor Davide Giacalone, University of Southern Denmark

Professor Thore Egeland, NMBU



Professor Paula Varela-Tomasco, NMBU and Nofima

Professor Tormod Næs, Nofima

Associate Professor Kristian Hovde Liland, NMBU

Associate Professor Gaston Ares, UdelaR, Uruguay

Summary of thesis

Childhood obesity is one of the most serious public health challenges of the twenty-first century (WHO, 2018). In this context, finding ways to make the healthier food choices the preferred ones, can be a valuable contribution to solving this multifaceted problem, as currently the majority of food marketed to children is unhealthy. Sensory and consumer methodologies are needed to support the development of healthy products that children will like and actively chose.

Two novel indirect methods were studied and compared to traditional questionnaire-based methods: implicit testing and biometrics. The Approach Avoidance Task (AAT) as a particularly easy implicit reaction time task assessed children’s implicit approach biases to different snack pictures. Results indicated a weak correlation of implicit bias to their expected liking ratings. Implicit testing seemed to be more related to concrete situational food preferences due to hunger state. Further, a procedure to facilitate a standardized self-administered tasting by children was established for facial decoding as biometrics measurement. Apart from implicit facial expressions, children were asked to explicitly indicate with their faces how they felt about the tasted sample. Implicit as well as explicit basic emotions correlated with liking ratings, but explicit facial expressions were the most discriminative measurement.

Further, Check-all-that-apply (CATA), an easy method to generate sensory descriptions of food products, was studied with children regarding individual differences in data quality according to ticking style (the way children used the CATA list). Children’s approach to the CATA task was studied by defining ticking style indicators: number of ticks, standard deviation of number of ticks per sample, and number of different attributes used in the test. Three groups of children were unveiled. Differences among groups may reflect different cognitive development levels. The findings highlighted, that the CATA method was more suitable for older children of the study (8 to 9 y. o. compared to 6 to 7 y.o.) but that individual differences in cognitive development within age group occurred.

This thesis provides novel methodologies with age-specific recommendations on how to include preadolescents in sensory and consumer studies which can serve the food industry as well as research for better understanding children’s perception of food and food testing procedures.

Papers in the thesis

  • Galler, M., Gonera, A., & Varela, P. (2020). Children as food designers: The potential of co-creation to make the healthy choice the preferred one. International Journal of Food Design, 5, 125-131.
  • Galler, M., Mikkelsen, E., Næs, T., Liland, K. H., Ares, G., & Varela, P. (2022, 2022/03/01/). Children’s sweet tooth: Explicit ratings vs. Implicit bias measured by the Approach avoidance task (AAT). Food Quality and Preference, 96, 104416.
  • Galler, M., Næs, T., L. Almli, V., & Varela, P. (2020, 2020/12/01/). How children approach a CATA test influences the outcome. Insights on ticking styles from two case studies with 6–9-year old children. Food Quality and Preference, 86, 104009.
  • Velázquez, A. L., Galler, M., Vidal, L., Varela, P., & Ares, G. (2022, 2022/03/01/). Co-creation of a healthy dairy product with and for children. Food Quality and Preference, 96, 104414.  


, , , , , ,