Contrast Enhancement (In Space and Time) For Food & Wine Interaction

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This is a follow up to a theory of wine-food interaction which a fair amount of people managed to read. In that post I attempted to explain wine and food interaction in terms of nutritional preference comparisons which change our construction of reality (like salting a tomato!) as well as strange changes in contrast detection similar to those that occur in black art theater. Recently, I’ve come across a great explanation of what I called “black art contrast pairings”.To explain the phenomenon I have to quote a large passage of Gordon M. Sheperd’s excellent new book, Neurogastronomy: How the Brain Creates Flavor and Why It Matters.

Ordinarily it might not be appropriate to republish an entire passage from a book, but Shepherd explains the phenomenon more articulately than I can paraphrase.

From Gordon M. Shepherd’s Neurogastronomy

Contrast Enhancement in Space and Time (Forming a Sensory Image p. 61)

“This effect had actually been described in humans by a German physicist named Ernst Mach in the nineteenth century. He had noticed that when we view a light-dark border, such as a sharp boundary between two walls with different illumination, the contrast is enhanced by a lighter band on the light side and a darker band on the dark side. These came to be called Mach Bands. You can see them yourself if you look for them. (The bibliography provides a site for you to look them up on the Internet.)

Hartline showed that Mach bands are present even in the primitive eye of Limulus (**horseshoe crab). He further showed the mechanism that produces them: lateral inhibitory connections between the receptor cells.  Through these connections, the strongly excited cells at the border more strongly inhibit the weakly stimulated cells, and the weakly stimulated cells more weakly inhibit the strongly excited cells. The mechanism is called lateral inhibition. The effect is called contrast enhancement, because the difference between the light and dark areas is enhanced at their boundary. In a general sense, contrast enhancement also is a kind of feature extraction, the enhanced response to specific spatial features in a visual scene.

This is contrast enhancement in space. Hartline’s laboratory also showed that there is contrast enhancement in time. When there is an abrupt step increase in illumination, a single cell responds with a large increase in impulse firing, which rapidly declines to a steady level somewhat higher than before. The overshoot in impulse frequency is called the phasic response, in contrast to the tonic response. It shows that the nervous system is sensitive primarily to a change in the environment rather than to an unchanging steady input. This contrast enhancement in time is the counterpart to contrast enhancement in space. After the initial increase in stimulation, lateral, as well as self-inhibition comes on to counterbalance the higher level of steady stimulation.”

There you have it. Wine pairings feature contrast enhancement over time. This does not explain what I felt was the result of nutritional preference comparisons, but I await or will search for that answer as well!

Feel free to notice the “think spatially” motto which has lived atop my blog for the last several years now. It should probably be changed to “you smell spatially” or something to that effect which is a big theme to Neurogastronomy. For the last several years I’ve been trying to describe flavor experiences with the language of space & attention.

So now what do we do with this new found information? Flavor is so multi-dimensional that now if we try and explain reactive pairings we may have to explain what resides on each side of the Mach Band created. In the last post I made on wine-food interaction I picked out all the holy grail pairings from What to Drink With What You Eat. I failed to explain them articulately but I should probably try again and consider the Mach Band concept.

If you anyone wants to help, feel free to lend a hand!

Another idea to consider when thinking of wine pairings is the technique of unsharp masking that is used in photography. In unsharp masking, when we overlap an image with a blurred or unsharp version of itself, changes in contrast detection happen. Following wine with food could create a similar effect to adding an unsharp mask which might explain phenomenons of contrast enhancement and feature extraction that characterize wine and food interaction. This all may be possible due to the spatial nature by which we perceive aroma.

Shepherd spends a lot of time explaining the spatial perception of aroma, but he doesn’t ever try to connect the concept with a simple enough analogy. I think what he is trying to get at is best expressed by the work of the 19th century perfumer, Septimus Piesse, who developed an Odophone which arranges aromas in tandem with musical notes on a scale. Piesse’s work is remarkably intuitive. The photo I’m linking to has been known to change lives and inspire career choices.

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