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Pavlov's Purple: Why Logos Make Me Hungry

21/04/2015 11:22 BST | Updated 20/06/2015 10:59 BST

We are immensely sensitive to food related imagery. To give you an idea of its potent and lasting effect on memory, the McDonald's logo has more global recognition than the Cross (Christian Cross), and a three year old will likely identify The Golden Arches faster than the letter M. Cadbury's has a trademark on the infamous purple Pantone (which is technical jargon for the word 'shade').

Food marketing is undeniably sophisticated. More of an art than a science, it can be difficult to know what will resonate with consumers. There are some pretty ingenious ways of reminding us to eat (more, and again). Just yesterday at dinner, I was presented an iPad with a collection of desert choices. Should my imagination fail upon merely reading the description of 'lavender crème brûlée' or 'triple sin chocolate lava cake', rest assured, the iPad was there to remind me of their look and perhaps even texture, as the chocolate lava cake had an iMovie to accompany it.

Yet, even without the pictures, just those words alone can evoke the desire to eat. Why?

The point here is not to draw attention to the decline in the average diner's imagination (or literacy). Rather, I'd like to take a moment to demonstrate the power of food related pictures and reminders, and also how our appetite could be exploited by iPads, message boards, and your friends Facebook feeds of what they had for dinner last night.

The discussion of food cues and appetite is not new. Pavlov could be considered the grandfather of psychology, along with his bells, dogs, and ability to teach animals to salivate to ringing sounds in addition to dinner food.

Further, slightly more recent animal research has demonstrated that we can learn to overeat- even binge eat- in proviso of the correct environmental settings. One necessary ingredient for cued binge eating? First and perhaps foremost, the animal has to be hungry for an extended period of time, i.e. the animal has to have been on a diet for a while. This is just more evidence to show how caloric restriction can inadvertently contribute to overeating. Of course, cued-binge eating is a scary concept, as we would probably never want to engage in binge eating in the first place, let alone set up an environment that promotes a binge eating response.

However, the point is to address why food cues elicit appetite in the first place. In doing so, we may gain a greater understanding for how we ate the entire piece of cake, or bag of m&m's.

The extended neural circuit that responds to food-related stimuli runs from the brain stem (the base, or nape of your neck) all the way to the frontal regions of the your forehead that are responsible for decision making. This circuit includes the lateral hypothalamus, the amygdala, medial prefrontal cortex, and orbitofrontal cortex. Both emotional reactions (like the reaction to great tasting food) and physiological reactions (like our response to ingesting energy) perpetuate learning, and decision-making.

Just above the brain stem, the lateral hypothalamus plays a major role in regulating energy balance. However, it's the emotional point that is most crucial: information from both the amygdala and prefrontal cortex concerning food cues may help override satiety signals. If we have a strong emotional connection with a certain food, afforded because it tastes nice, a representation of it- be that a logo, picture, word, or even an emotional state (which, by the way is called a 'craving')- will trigger the motivation to eat.

Just like rats on a diet, or Pavlov's dog,: we will seek out Cadbury Pantone C2685C if a situation (or food) has enough emotional potency to dim the parts of the brain that respond to satiety. We eat for thrills, not just energy balance.

Neuroimaging technology has provided researchers with observational tools to explore the impact of food cues, and differences within populations. It may not be a surprise that obese individuals are more sensitive to food cues than lean, and women are more sensitive still. Perhaps because women start dieting at younger ages, they make their brains more sensitive to food related imagery and cues, and reinforce emotional- as opposed to physiological- connections with eating. Perhaps women are also more likely to binge eat, or struggle with the idea of binge eating.

By gaining an understanding of the way that food images work on neural circuitry, we gain a greater insight into the subtle factors that impact our so-called choice.

Well. Pictures of lavender crème brûlée and chocolate cake are about as subtle as a sledgehammer, but even things like colour, scent, time of day, and mood states can contribute to the internal mélange that produces the reaction of eating outside of physiological need.

So there we go: a lesson in animal behavior, gender studies, and neuroscience all wrapped up in around 800 words. Now quick: PURPLE. CHOCOLATE. BUTTONS.

.... See what I did?