A Dog Might Trade His Favorite Meal for a Bowl in His Preferred Color, Study Finds!

Animal Cognition is shaking up certain received ideas. By observing the spontaneous choices of Indian street dogs in the face of colorful objects, scientists have discovered a marked attraction for yellow color, to the point of sometimes surpassing the attraction of food.

A careful methodology to understand spontaneous choices

The researchers adopted a methodical and rigorous approach to avoid biases and guarantee the reliability of the results. They only selected healthy adult dogs. They had met them randomly in urban, semi-urban and rural areas of the Kolkata region. Each dog was only tested once, without repetition or prior observation of other tests. Any influence related to learning or curiosity induced by the experience itself had to be dismissed. This method, called “one-time multi-option choice test”, makes it possible to measure a spontaneous reaction. It is intended to reflect the intrinsic preferences of the animal, without prior conditioning. The use of dogs living freely, without regular contact with humans, also guarantees that their choices are not influenced by domestic learning or a preexisting association between color and reward.

The protocol was based on a simple, but controlled situation. Three bowls of terracotta identical, differentiated only by their color – yellow, blue or gray – were placed at equal distance from the dog. This choice of colors is based on the visual capacities known to dogs. Indeed, they mainly perceive the shades of blue and yellow. Red and green appear for them in the form of gray. By alternating conditions with or without food, the researchers were able to verify whether the attraction for a color persisted independently of the presence of food reward. The location of the bowls was also rearranged with each test to avoid any position bias.

Yellow with food: a color preference that challenges logic

To assess the solidity of this preference in the face of a vital issue like food, the team subjected dogs to a more difficult choice. Two distinct dogs of dogs have been tested, each being confronted only once with experience. The first group of 52 dogs had to choose between a gray bowl containing a quarter of cookie and an empty yellow bowl.

Among them, 41 dogs, almost 79 %, have chosen to approach the yellow bowl directly, ignoring food. A second group of 61 dogs was subjected to the same protocol, but with raw chicken – a more appetizing food for stray dogs. Again, 47 dogs, about 77 %, favored the empty yellow bowl. This persistent visual attraction, observed despite the strong food motivation of street dogs, surprised the researchers themselves. They logically expected to see the food to take over on a simple visual stimulus.

The team had to eliminate any possibility that this preference was linked to residual odors. The researchers then implemented a control experience. They covered the colored sieve bowls, preventing dogs from seeing the color. But the smells passed. Drive of visual index, dogs have shown completely random choices. This confirmed, according to Roy and Bhadra, that the preference for yellow is based solely on visual perception. This rigorous protocol made it possible to rule out olfactory biases.

Why the color yellow? Tracks between environment and evolution

Several hypotheses are envisaged to explain this unexpected preference. The theory of ecological valenceadvanced by Palmer and Schloss in 2010, proposes that animals develop an affinity for colors associated with vital resources. In the case of Indian street dogs, human food is omnipresent in their diet. However, it frequently contains spices such as turmeric or dried chilli, appearing yellow in their eyes. Even blood or raw meat, perceived as red by humans, take a yellowish shade in canine vision. “” If this preference was anchored during the evolution, it could go back to the wild ancestors of dogs, wolves “, Advises Anindita Bhadra.

Another hypothesis is based on confidence of species. This is a trend observed in other animals to favor the colors present on their fellows. Many Indian dogs wear brown or red coat. In their visual spectrum, this approaches yellow. However, this explanation struggles to justify why no particular rejection was observed for blue or gray.

Researchers also note that similar experiences carried out in Morocco, on a different population of stray dogs, had not revealed any chromatic preference. This contrast suggests that the relationship between dogs and yellow color could be partially linked to local environmental factors. We can even assume a form of cultural learning, in addition to a possible evolutionary bias. Comparative studies will be necessary to check whether this preference for yellow exists in pet dogs or even wolves.

Source: Anamtra Roy et al., “Ready, set, yellow! Color Preference of Indian Free-Ranging Dogs ”, Animal cognition (2025).