How we discovered that people who are colorblind are less likely to be picky eaters

Isabel Gauthier, Vanderbilt University

The seventh season of Julia Child’s “The French Chef,” the first of the television series to air in color, revealed how color can change the experience of food. While Child had charmed audiences in black and white, seeing “Bouillabaisse à la Marseillaise” in color helped elevate the experience from merely entertaining to mouthwatering.

I am a psychologist who studies visual abilities. My work, through a serendipitous research journey into individual differences in food recognition, uncovered a unique role for color in emotional responses to food.

People vary in their ability to recognize food

This journey started when my students and I measured how people vary in their ability to recognize images of prepared food. Over the past 20 years, we and other researchers have learned that people vary more than originally suspected in how well they discriminate and identify objects, like birds, cars or even faces.

It seems obvious that some people know more than others about birds or cars. Yet, interestingly, there is as much variation in face recognition ability, even though virtually every sighted person has experience seeing faces.

Experience with food is also universal. We were curious how much people would vary in their ability to recognize food items. Our tests simply ask people to match images of the same dish among similar ones, or to find the oddball dish among others. People vary a great deal on these tasks, and some of this variation is explained by a general ability to recognize objects of any kind.

But a portion of the food recognition differences among people was not explained by this general ability. Instead, we speculated that this variability may be related to people’s attitude toward new foods. People who strongly endorse statements like “I don’t trust new foods” or “I am very particular about the foods I eat” have what’s called food neophobia. It can lead to poor diet quality, resulting in nutritional deficiencies and higher risk of chronic disease.

As we predicted, we found that picky eaters scored worst on our tests of food recognition: Food neophobia is negatively correlated with food recognition ability.

Color connects food neophobia to recognition

While we were publishing our results, other scientists were debating new findings about how the brain reacts to food and color. Different research groups had identified brain areas in the visual system that responded preferentially to images of food. For instance, looking at a bowl of pasta would activate these brain areas, but not looking at a pile of string.

The scientific disagreement was about what it meant to identify a selectivity for food in areas of the brain already known for their responsiveness to color.

One group proposed that these parts of the brain responded to color because they are specialized to recognize food. The other group argued that color was not critical to the brain’s response to food. They even showed they could get similar brain activation when people looked at gray-scale images of food.

Was it possible that color was not critical to food recognition, while still playing a special role? We decided to replicate our initial study, with images of food in gray scale.

The results could have been predicted by Child herself: Without color, people unsurprisingly made a few more errors and mistook different dishes as the same kind of food, but the pattern of variation across people was otherwise unchanged. Those with a higher general visual ability did better with food, and we again found a specific ability for food that goes beyond this general effect.

But we did find one effect of removing color: food neophobia was no longer correlated with food recognition ability. It was as if whatever advantage the adventurous eaters had gained over picky eaters was all dependent on color.

Based on these results, we proposed two separate components of food-specific recognition ability. One is independent of color and explains why the results are the same in the experiments with and without color. The other one, related to emotional responses, is based on color and evidenced by the finding that food neophobia is only related to food recognition when the food appears in color.

We then made an entirely new prediction: Would people with color blindness – men, really, because color blindness affects 16 times more men than women – be less food neophobic than those with normal color perception? Because someone who is colorblind experiences food in a restricted range of color, some of the signals that raise flags about freshness, safety or otherwise drive anxiety about novel food could be limited.

We recruited participants online, including men in our study based on how they answered one question about color blindness that was buried in a long screening questionnaire. Our participants had no idea that we were interested in color blindness when we asked them then to fill out the Food Neophobia Scale that measures how resistant people are to new foods.

We found that colorblind men were indeed less food neophobic than non-colorblind men. We replicated this finding in another study, with colorblind men also reporting lower levels of food disgust. Seeing the world with a restricted color palate seems to mitigate an emotion-based resistance to new foods.

Color and emotional responses to food

Our research is broadly consistent with other findings. Color can help you decide whether food is cooked or if produce is ripe or rotten, and people tend to prefer meals with a range of colorful foods. Other research shows that color can influence what food tastes like. Some biologists have argued that the coloration of plants and the ability of animals to detect it have co-evolved.

The role of color in emotional responses to food opens up new avenues for addressing extreme cases of food neophobia. As researchers learn more about the intricate relationship between color perception and food, we might develop targeted interventions to improve dietary habits. Just like Julia Child’s colorful dishes, understanding and leveraging the power of color could enhance the appreciation and enjoyment of food.

Isabel Gauthier, David K. Wilson Professor of Psychology, Vanderbilt University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Jisoo successfully defended her dissertation “The Role of Attention Control in Ensemble Perception in the Presence of Selection” on May 6th, in the presence of her committee members Tom Palmeri, Marcia Barnes, Randolph Blake and proud advisor, Isabel.

Teller award details

And our colleague, Randolph Blake has won The Ken Nakayama Medal for Excellence in Vision Science. A good year for our department 🙂

The same people excel at object recognition through vision, hearing and touch – another reason to let go of the learning styles myth

Isabel Gauthier, Vanderbilt University and Jason Chow, Vanderbilt University

The idea that individual people are visual, auditory or kinesthetic learners and learn better if instructed according to these learning styles is one of the most enduring neuroscience myths in education.

There is no proof of the value of learning styles as educational tools. According to experts, believing in learning styles amounts to believing in astrology. But this “neuromyth” keeps going strong.

A 2020 review of teacher surveys revealed that 9 out of 10 educators believe students learn better in their preferred learning style. There has been no decrease in this belief since the approach was debunked as early as 2004, despite efforts by scientists, journalists, popular science magazines, centers for teaching and YouTubers over that period. A cash prize offered since 2004 to whomever can prove the benefits of accounting for learning styles remains unclaimed.

Meanwhile, licensing exam materials for teachers in 29 states and the District of Columbia include information on learning styles. Eighty percent of popular textbooks used in pedagogy courses mention learning styles. What teachers believe can also trickle down to learners, who may falsely attribute any learning challenges to a mismatch between their instructor’s teaching style and their own learning style.

Myth of learning styles is resilient

Without any evidence to support the idea, why do people keep believing in learning styles?

One possibility is that people who have incomplete knowledge about the brain might be more susceptible to these ideas. For instance, someone might learn about distinct brain areas that process visual and auditory information. This knowledge may increase the appeal of models that include distinct visual and aural learning styles. But this limited understanding of how the brain works misses the importance of multisensory brain areas that integrate information across senses.

Another reason that people may stick with the belief about learning styles is that the evidence against the model mostly consists of studies that have failed to find support for it. To some people, this could suggest that enough good studies just haven’t been done. Perhaps they imagine that finding support for the intuitive – but wrong – notion of learning styles simply awaits more sensitive experiments, done in the right context, using the latest flavor of learning styles. Despite scientists’ efforts to improve the reputation of null results and encourage their publication, finding “no effect” may simply not capture attention.

But our recent research results do in fact contradict predictions from learning styles models.

We are psychologists who study individual differences in perception. We do not directly study learning styles, but our work provides evidence against models that split “visual” and “auditory” learners.

Object recognition skills related across senses

A few years ago, we became interested in why some people become visual experts more easily than others. We began measuring individual differences in visual object recognition. We tested people’s abilities in performing a variety of tasks like matching or memorizing objects from several categories such as birds, planes and computer-generated artificial objects.

Using statistical methods historically applied to intelligence, we found that almost 90% of the differences between people in these tasks were explained by a general ability we called “o” for object recognition. We found that “o” was distinct from general intelligence, concluding that book smarts may not be enough to excel in domains that rely heavily on visual abilities.

Discussing this work with colleagues, they often asked whether this recognition ability was only visual. Unfortunately we just didn’t know, because the kinds of tests required to measure individual differences in object perception in nonvisual modalities did not exist.

To address the challenge, we chose to start with touch, because vision and touch share their ability to provide information about the shape of objects. We tested participants with a variety of new touch tasks, varying the format of the tests and the kinds of objects participants touched. We found that people who excelled at recognizing new objects visually also excelled at recognizing them by touch.

Moving from touch to listening, we were more skeptical. Sound is different from touch and vision and unfolds in time rather than space.

In our latest studies, we created a battery of auditory object recognition tests – you can test yourself. We measured how well people could learn to recognize different bird songs, different people’s laughs and different keyboard sounds.

Quite surprisingly, the ability to recognize by listening was positively correlated with the ability to recognize objects by sight – we measured the correlation at about 0.5. A correlation of 0.5 is not perfect, but it signifies quite a strong effect in psychology. As a comparison, the mean correlation of IQ scores between identical twins is around 0.86, between siblings around 0.47, and between cousins 0.15.

This relationship between recognition abilities in different senses stands in contrast to learning styles studies’ failure to find expected correlations among variables. For instance, people’s preferred learning styles do not predict performance on measures of pictorial, auditory or tactile learning.

Better to measure abilities than preferences?

The myth of learning styles is resilient. Fans stick with the idea and the perceived possible benefits of asking students how they prefer to learn.

Our results add something new to the mix, beyond evidence that accounting for learning preferences does not help, and beyond evidence supporting better teaching methods – like active learning and multimodal instruction – that actually do foster learning.

Our work reveals that people vary much more than typically expected in perceptual abilities, and that these abilities are correlated across touch, vision and hearing. Just as we can expect that a student excelling in English is likely also to excel in math, we should expect that the student who learns best from visual instruction may also learn just as well when manipulating objects. And because cognitive skills and perceptual skills are not strongly related, measuring them both can provide a more complete picture of a person’s abilities.

In sum, measuring perceptual abilities should be more useful than measuring perceptual preferences, because perceptual preferences consistently fail to predict student learning. It’s possible that learners may benefit from knowing they have weak or strong general perceptual skills, but critically, this has yet to be tested. Nevertheless, there remains no support for the “neuromyth” that teaching to specific learning styles facilitates learning.

Isabel Gauthier, David K. Wilson Professor of Psychology, Vanderbilt University and Jason Chow, Ph.D. Student in Psychological Sciences, Vanderbilt University

This article is republished from The Conversation under a Creative Commons license. Read the original article.