Do facial reactions add new dimensions to measuring sensory responses to basic tastes?

Basic taste solutions induce sensory perceptions via taste receptors and give rise to specific facial reactions. Many of these have been shown to be innate. The aim of this study was to explore relationships between the sensory perception of basic taste solutions at different concentrations and facial reactions.Basic taste solutions each at three levels plus water were served to a panel. The assessors individually identified quality, intensity and pleasantness. They were recorded during tasting and their facial reactions (based on FACS) were coded and analysed.Facial reactions indicated both quality and concentration of the stimuli. The intensity of most facial reactions increased with increasing stimulus concentration, most pronounced for sourness (lips) and bitterness (eyes and forehead). Pleasantness ratings decreased with increasing concentrations of all basic tastes. Water and the lowest sucrose concentration were perceived as the most pleasant samples and gave rise to the lowest intensity of facial reactions. The study showed that a combination of sensory analyses and facial expressions was successful in adding further insight to the knowledge of perception of basic tastes.

Research highlights
► Basic taste solutions were examined by sensory analysis and facial reactions.
► Facial reactions indicated quality and concentration of the stimuli.
► The intensity of facial reactions increased with increasing stimulus concentration.
► Facial reactions most pronounced for sour (lips) and bitter (eyes and forehead).
► Pleasantness ratings decreased with increasing concentrations of all basic tastes.