This feature is part of Colorscope, an award-winning series exploring our perception of color and its use across cultures, one shade at a time. See more here .

(CNN) Ever heard that if you looked at the color yellow for too long, you might begin to feel anxious or irritated? Or that babies are more likely to cry in yellow rooms and a colleague sporting the color would be judged deeply? Or considered a coward?

The rumors are out there, and have been for some time.

If you Google search "How yellow affects your mood", amid positive reviews of the color, a plethora of websites will also appear that warn against yellow's agitating qualities.

"That's absolutely not true," said Leatrice Eiseman, color specialist and executive director of the Pantone Color Institute, which helps companies decide which colors are best for their brands or products.

Eisman knew the originator of that rumor, she said, adding that "he is now long dead."

His name was Carleton Wagner, and he ran a school for people interested in color, she said.

"Yellow was not his favorite color and he did all he could to disparage the use of it, but that was strictly from a personal standpoint, and it's taken on a life of its own," Eiseman said.

In fact, yellow mostly has the opposite effect on people, she argued.

Making you happy

Through her research, Eiseman has conducted various color word association studies on thousands of people over the last 30 years. The first words that consistently come to mind when people see the color yellow are "sunshine", "warmth", "cheer", "happiness" and sometimes even "playfulness".

This stems from its association with a crucial player in our solar system -- the sun.

"Give any child a box of crayons and they reach for the yellow crayon," said Eiseman. "And invariably in the upper right hand corner or left hand corner will appear the ball of sun and often with the rays emanating out."

The sun wakes us up, keeps us warm and feeds our crops. When it is out of the clouds, children are told to go play.

Although the sun is actually white, we perceive it as yellow or orange because these colors have higher wavelengths and are scattered less easily by Earth's atmosphere, leaving them behind intensely for us to see. Blue, on the other hand, has low wavelengths, which explains why it is strewn across the sky.

Proving the soul-warming qualities of yellow, Eiseman has painted the main area of her own house the color. She lives in Washington, where the days are often gray and dismal and the yellow makes her feel like she has bathed in sunlight, she said.

The use of yellow to cheer people up can be traced back to London in 1917, according to "The Colour Treatment: A Convergence of Art and Medicine at the Red Cross Russell Lea Nerve Home", by Jim Berryman. It was World War I, and a "colorist" named Howard Kemp Prossor believed that the right color scheme in a hospital room could cure soldiers who were shell-shocked.

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He designed a room at Ethel McCaul's Hospital in London, with sky blue ceilings, delicate green floors and lemon yellow walls.

Although it was acknowledged that the room felt cheerful, an army doctor concluded that this psychological treatment was not as reliable as other therapeutic methods, according to "The Colour Treatment: A Convergence of Art and Medicine at the Red Cross Russell Lea Nerve Home" by Jim Berryman.

There have been few conclusive studies on how the color yellow alone affects people biologically. But Eiseman said the general mood that accompanies the color is mostly a positive one.

In her research, she has seen people associate yellow with even deeper feelings than happiness. "Sometimes people who are very metaphysical will see enlightenment," she said.

Can yellow treat depression?

Yellow's mood improving qualities could be assumed to help seasonal affective disorder -- a specific type of depression that reoccurs each year during fall and winter, and is believed to be influenced by lack of sunlight.

Some people with seasonal affective disorder choose to wear yellow tinted glasses, which block out blue light rays. These blue light rays are what produce melatonin in the body, and lead to oversleeping; a symptom that can be prevalent in those who have the disorder.

Light therapy has been proven to help treat the disorder, through a portable fluorescent light box placed inside the patient's home, providing a balanced spectrum of light that gives a similar feeling to standing outside on a pleasant sunny day.

But does yellow have anything to do with it? Although it is her favorite color, psychologist Gila Lindsley of LaMora Psychological Associates doesn't think so.

"People get better through these [boxes], which is wonderful, but that's just because that part of the brain that controls it all is responsive to the particular light spectrum in sunlight," Lindsley said. "There are particular cells in the eyes that'll respond to it and basically tell the biological clock what time it is. So it's by coincidence that yellow's cheery."

Appearing different through evolution

There's also something different about yellow's physical appearance. When made darker or lighter, it behaves in a way that no other primary color does, and scientists have no idea why -- but it may have played an important role in how our visual perception evolved.

Steven Buck, a professor in the neuroscience graduate program at the University of Washington, said yellow is the only color that changes its hue when it's made darker than its surroundings.

The yellow completely disappears, and it becomes brown. When brown is made lighter, it becomes yellow.

In contrast, people's perception of red, blue and green stays the same despite how bright or dark they are.

"It could be that its been important in our evolution to distinguish objects, surfaces, that have the sort of wavelength composition that yellow has when its bright, but are dark instead," Buck suggested to CNN.

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Another explanation may be that since brown is such a common color found in natural environments that may not have a lot of meaning, it could have been useful to us to perceive certain objects as a brighter hue like yellow, he said. Yet, he doesn't know anything definitively.

"Really, I don't think anyone knows how to do experiments about why we evolved the way we did," Buck said. "But something about the difference between bright surfaces that look yellow and the corresponding dark surfaces that look brown has been important in the evolution of the visual system."

Can you see it?