Sensory science is one of the most delicate areas of wine science, as the sensory mechanisms are only beginning to be understood, and questions of subjectivity abound.
At WAC 2014, Wendy Parr of Lincoln University in New Zealand launched the sensory session with a provocative introduction. She asserted that sensory science takes on two major identities in wine science, first as a sort of “nexus” linking culture, psychology, oenology and viticulture, where it plays a “collaborative” or supplementary role in projects aiming to understand the effects of different winemaking or grape growing practices. The second face of sensory science is as a discipline in its own right. A discipline based in psychology that “makes the role of the perceiver explicit.” When seen in this way, she argues, sensory science can allow for the integration of psychological phenomena to understand individual differences between tasters or the impact of context – the order the wines are presented, the background noise in a room, even the mood of the taster herself when evaluating a wine. In the collaborative approach of sensory science, these individual and contextual variables are seen as sources of error, and thus researches strive to “eliminate” and “control” them at all costs. Costs that, in some cases, can be extreme, resulting in conditions so far removed from reality that the study results are near-meaningless in the real world. Thus more research in the second sense, with sensory science being done for the sake of sensory science, could help us to understand physiological differences between individuals and the impact of contextual factors, which ultimately might make our wine science more relevant.
Psychologist Anthony Saliba of Charles Sturt University in Australia picked up on this theme of contextual and individual factors, elucidating the nature of these sources of “error” with a series of examples. He discussed how humans are much more influencible than we tend to think. This influence could come from within, with physiological phenomena, or from the exterior – contextual cues that change our perception without us even realizing it.
For example, individual variation in sensory thresholds (the minimum concentration of a substance for it to be perceptible) is a physiological constant – humans cannot be trained to smell a substance at a concentration lower than their individual threshold level. Optical and auditory illusions, such as a musical scale that seems to continuously go up or down, demonstrate the fallibility of our senses. Yet it is these same senses, limited by physiological factors, that hold us so tightly at their mercy.
Continuing with the theme of sensory tricks, neuroscientist Gil Morrot from the University of Montpellier described a study in which the best sommeliers of France were able to blindly identify the region of origin of Bordeaux or Burgundy wines in only about 50% of cases. If even these experts can be tricked, clearly our physiological limitations are inhibitory. Moreover, he discussed the important influence of wine color on our perception. Our descriptions and differentiations of wines are principally based on a color-based dichotomy, but we know that we can so easily trick tasters into mixing up red and white wines when they can’t see the color. It turns out that unlike sight or hearing, which each activate a specific region of the brain, olfaction causes a global activation – activating parts of the brain normally responsible for the other senses. Thus we cannot smell properly without seeing, explaining the close link between color and sensory perception in wines.
All this taken into account strongly supports Wendy Parr’s call for sensory science to be practiced as a “real” science in its own right. The understanding of such sensory phenomena can allow us to delve deeper into our sensory studies, hopefully developing methods that can take into account individual variation and contextual influences, rather than simply eliminating them. Thus we can begin to foster a more holistic approach to sensory science, rather than cutting out factors that could turn out to be detrimental to the applicability of the results.