Our eyes “see” and create health perception

  • April 22, 2013
  • Sophie Langley

People sometimes “see” flavours in foods and beverages before actually tasting them, according to a scientist speaking at a meeting of the American Chemical Society on 11 April 2013.

The eyes sometimes beat the tongue, nose and brain in the emotional and biochemical balloting that determines the taste and allure of food, according to Terry E. Acree, Ph.D, a Professor of Food Science at Cornell University in New York.

“There have been important new insights into how people perceive food flavours,” Professor Acree said. “Years ago, taste was a table with two legs – taste and odor. Now we are beginning to understand that flavour depends on parts of the brain that involve taste, odor, touch and vision. The sum total of these signals, plus our emotions and past experiences, result in perception of flavours, and determine whether we like or dislike specific foods,” he said.

Professor Acree said that people can actually see the flavour of foods, and the eyes have such a powerful role that they can trump the tongue and the nose. The white wine variety Sauvignon Blanc, for example, gets its flavour from natural chemicals with the flavor of banana, passion fruit, capsicum and boxwood. But when served a glass of Sauvignon Blanc tinted to the deep red of a merlot or cabernet variety, people taste the natural chemicals that give rise to the flavours of those red wines.

While the appearance of foods is important, other factors can override it, Professor Acree said. For example, he said, many stews and curries have an unpleasant look similar to vomit or faeces, but people savour these dishes, perhaps based on the memory of eating and enjoying them in the past. The human desire for novelty and new experiences is also a factor in the human tendency to ignore what the eyes may be tasting, and listen to tongue and nose, said Professor Acree.

Smell also affects taste. In a test that could easily be replicated at home, psychologists have asked volunteers to smell caramel, strawberry or other sweet foods and then take a sip of plain water. The volunteers reported that the water tasted sweet. But if the volunteers smelt bread, meat, fish or other non-sweet foods, the water did not taste sweet.

Professor Acree said that understanding the effects of interactions between smell and vision and taste, we well as other odorants, will open the door to developing healthful foods that look and smell more appealing to fussy eaters.

Green food labels may make food seem healthier

Meanwhile, other research from Cornell University, published in February 2013 in the academic journal Health Communication, found that the way food looks could also affect consumers’ perceptions of its healthfulness.

“Our research suggests that the colour of calorie labels may have an effect on whether people perceive the food as healthy, over and above the actual nutritional information conveyed by the label, such as calorie content,” said the study’s author, Jonathon Schuldt, who is Assistant Professor of Communication and Director of Cornell’s Social Cognition and Communication Lab.

For the study, 93 university students were shown an image of a candy bar with either a red or a green nutrition label, and asked them which they thought contained more calories, and which was the healthier option. The students perceived the green-labelled confectionary as more healthful than the red one, even though the calorie content was the same.

Assistant Professor Schuldt repeated the experiment with 39 online participants, this time with a white-labelled and green-labelled candy bar. He found that the more importance participants placed on healthy eating, the more they perceived the white-labelled candy bar as less healthful – a pattern that was eliminated when the candy bar had a green label.

“The green calorie labels butter relatively poor nutrition foods from appearing less healthful among those especially concerned with healthy eating,” Assistant Professor Schuldt said.

The study could have implications for nutrition labelling, given that front-of-package calorie labels have become increasingly common in the food marketplace in the US and Europe.

“As government organisations, including the US Food and Drug Administration, consider developing a uniform front-of-package labelling system for the US marketplace, these findings suggest that the design and colour of the labels may deserve as much attention as the nutritional information they convey,” Assistant Professor Schuldt said.

Australian food colour-code labelling

Meanwhile, there has been an ongoing debate about food labelling legislation in Australia. Australian Food News reported as early as December 2011 that Australian State and Territory food ministers were to investigate a suitable front-of-pack nutrition labelling model as an alternative to the Traffic Light System used in the US and UK, or a food industry-favoured Dietary Intake System.

In some Australian jurisdictions, a form of colour-coding for foods or beverages is being used for guidelines with a view to improving children’s consumption habits.


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