Why Humans See More Colors than Dogs, but Fewer than Birds and Insects
“What we perceive as color — what we perceive as light — corresponds to a very narrow band of frequencies, out of an infinite continuum," says Nobel Laureate Frank Wilczek.
Frank Wilczek is an American theoretical physicist, mathematician and a Nobel laureate. He is currently the Herman Feshbach Professor of Physics at the Massachusetts Institute of Technology (MIT). Wilczek, along with David Gross and H. David Politzer, was awarded the Nobel Prize in Physics in 2004 for their discovery of asymptotic freedom in the theory of the strong interaction. He is on the Scientific Advisory Board for the Future of Life Institute. His new book is titled A Beautiful Question: Finding Nature's Deep Design.
Frank Wilczek: In the nineteenth century with Maxwell’s synthesis of the laws of electricity and magnetism physicists started to realize that what we perceive as light is deeply understood as a kind of disturbance, electric and magnetic fields. That gave us a new concept of the possibilities of perception of light that show us that we’re missing a lot. The electromagnetic equations permit radiation of any wave length and of any frequency – what we perceive as color – what we perceive as light is corresponds to a very narrow band of frequencies out of an infinite continuum. Not only that but even within that band we take three averages. We don’t sample all the different frequencies but just three averages. That’s called trichromatic vision. So for instance in computer displays there are three different kinds of lighting elements used. When you see on your menu the choice of millions of different colors that doesn’t mean different lighting arrangements, lighting possibilities. It means different combinations, different relative intensities of just three. Any perceived color can be synthesized from three basic colors.
Other creatures see less. Dogs, for instance, see only two kinds of colors like color blind people see basically only two kinds of colors. Other creatures see more. Other creatures – many insects and birds see four or five colors. They also sample kinds of light, kinds of electromagnetic radiation that humans don’t see. There’s infrared radiation. There’s ultraviolet radiation. Maxwell’s equations which describe light also describe radio waves and microwaves and x-rays and gamma rays. So all those things are possible forms of vision that human’s natural endowment doesn’t tap into. But it’s out there. On the one hand it’s very important to make concepts visual because it taps into very powerful methods of processing that we have. And on the other hand scientific knowledge of what light is shows us that our natural perception leaves a lot on the table and so it leaves us with the program of doing better with telescopes, microscopes, spectrometers and other kinds of gadgets that I’m developing for everyday life that will allow us to see more colors.
The human perception of color is limited really by the principles of quantum mechanics. It’s interesting to compare the human perception of color to the perception of sound. Our perception of sound in one way is much richer. When you have two pure tones together like a C and a G, a simple chord that’s a fifth. If you hear that you can hear the separate tones even though they’re played together and you hear a chord. You can also sense the separate tones and if one is louder than the other you can continuously judge how their relative intensity. Whereas with colors if you mix two different – if you have two different colors say spectral green and spectral red and mix them what you see is not a chord where you can see the distinct identities preserved but rather an intermediate color. In fact you’ll see something that looks like yellow. The perception of color sort of throws away the detailed resolution, detailed accounting of the different kinds of underlying tones, different kinds of pure frequencies or pure colors that are underlying the perception. Our perception of that kind of mixture is indistinguishable from our perception of a pure spectral yellow such as you’d see in a rainbow.
It’s as if in music when you played a C and a G together instead of hearing a chord you just heard the note E, the intermediate note. On the other hand visual information is much richer in conveying the spatial structure of things. We get a detailed image whereas sound gives much poorer spatial resolution. And there are good physical reasons for those things. Sound waves are relatively slow – oscillate relatively slowly so that mechanical vibrations inside our ear and electrical processes inside our brain can keep up with them and so we can keep that kind of time structure. We can keep track of it. That’s why we do a good job with chords. Whereas the oscillations in electromagnetic radiation are very, very fast. Much faster than any mechanical system can keep up with or that nerve firings can keep up with. So the way we process that is quite different. It’s an all or none process where photons get absorbed and trigger changes in the structure of proteins. And we have three kinds of proteins and three different kinds of cone cells that give us three kinds of average responses. And that’s why you can synthesize any perceived color with just three.
"In the nineteenth century, with Maxwell’s Synthesis of the Laws of Electricity and Magnetism, physicists started to realize that what we perceive as light is deeply understood as a kind of disturbance of electric and magnetic fields." Frank Wilczek says. "That gave us a new concept of the possibilities of perception of light, that show us we’re missing a lot."
In fact, there is a lot to light that we as humans can’t see.
"What we perceive as color — what we perceive as light — corresponds to a very narrow band of frequencies, out of an infinite continuum. Not only that, but within that band we take three averages."
These averages are made up of the three primary colors. These three colors mix and match to make up the rest of our field of vision, which is known as tri-chromatic vision.
"In computer displays, there are three different kinds of lighting elements used." Wilczek explains. "When you see on your menu, the choice of millions of different colors, that doesn’t mean different lighting arrangements or possibilities. It means different combinations, different relative intensities of just three. Any perceived color can be synthesized from three basic colors."
Not all animals have three cones of vision, dogs are known to have only two, while some other animals have more. These animals not only can see more colors than we as humans do, but can "sample" light in different ways than humans, such as infrared and ultra violet light. For now, in our current natural state of being, we can’t see them.
"Our perception of sound, in one way, is much richer." Wilczek says. When a chord is played on an instrument, we are able to differentiate between the notes being played, we hear them as separate notes played at the same time. But when two waves of light, two colors hit each other, such as red and blue, we see them as one beam of light: purple.
"Our perception of that mixture is indistinguishable from a pure spectral yellow such as you’d see in a rainbow. It’s as if in music, when you play a C and a G together, instead of hearing a chord, you just heard the note E."
This has a lot to do with how fast the waves oscillate. Sound waves are relatively slower, allowing our brains to keep up with the way they move, while light waves oscillate faster.
"The way we process that is quite different, it’s an all or none process where photons get absorbed and trigger changes in the structure of proteins. We have three kinds of proteins, and three different kinds of cone cells, that give us three kinds of average responses. And that’s why you can synthesize any perceived color with just three."
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New study suggests the placebo effect can be as powerful as microdosing LSD.
- New research from Imperial College London investigated the psychological effects of microdosing LSD in 191 volunteers.
- While microdosers experienced beneficial mental health effects, the placebo group performed statistically similar to those who took LSD.
- Researchers believe the expectation of a trip could produce some of the same sensations as actually ingesting psychedelics.
Psychedelics: The scientific renaissance of mind-altering drugs<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="92360c805fe66c11de38a75b0967f417"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/5T0LmbWROKY?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>For the study published in eLife, the team recruited 191 citizen cosmonauts to microdose either LSD or a placebo over the course of several weeks and note the psychological effects. Volunteers were already microdosing LSD, so there was no true control. Each volunteer was given instructions on creating their own low-dose gel capsules, some containing LSD, others not. Then they mixed the capsules in envelopes so they didn't know if they were taking the real thing or not.</p><p>The trial design was ingenious: each capsule featured a QR code that was scanned after the addition of ingredients but before they were placed in the envelope so that researchers knew what they were ingesting.</p><p>The problem: volunteers sourced their own LSD. Lack of quality control could have had a profound effect on the results. </p><p>The results: LSD microdosers reported feeling more mindful, satisfied with life, and better overall; they also noticed a reduction in feelings of paranoia. </p><p>The catch: the control group felt the same thing, with no statistical difference between the groups. </p><p>Lead author Balázs Szigeti comments on the findings: "This suggests that the improvements may not be due to the pharmacological action of the drug but can instead be explained by the placebo effect." </p>
Credit: Alexander / Adobe Stock<p>Psychedelics are notoriously difficult to control for given the intensity of the experience. Yet there is precedent for the above findings. A <a href="https://link.springer.com/article/10.1007/s00213-020-05464-5" target="_blank">2019 study</a> found that 61 percent of volunteers that took a placebo instead of psilocybin felt some psychedelic effects, with a few volunteers experiencing full-on trips.</p><p style="margin-left: 20px;">"Several stated that they saw the paintings on the walls 'move' or 'reshape' themselves, others felt 'heavy. . . as if gravity [had] a stronger hold', and one had a 'come down' before another 'wave' hit her."</p><p>The Imperial team believes the expectation of a trip might have been enough to produce similar results. Senior author David Erritzoe is excited for future studies on the topic, believing they tapped into a new wave of citizen science that could push forward our knowledge of psychedelic substances.</p><p style="margin-left: 20px;">"Accounting for the placebo effect is important when assessing trends such as the use of cannabidiol oils, fad diets or supplements where social pressure or users' expectations can lead to a strong placebo response. Self-blinding citizen science initiatives could be used as an inexpensive, initial screening tool before launching expensive clinical studies."</p><p>As investments into the psychedelics market explode, with one company <a href="https://www.bloomberg.com/news/articles/2021-03-03/thiel-backed-magic-mushroom-firm-atai-hits-2-billion-valuation" target="_blank">reaching a $2 billion valuation</a>, a recurring irony appears in the long arc of psychedelics and research: the power of our minds might be enough to feel greater life satisfaction and a deeper sense of mindfulness. If that's possible with a placebo, we have to question why the rush to create more pharmacology is necessary. </p><p>This is, mind you, a separate conversation over the role of psychedelics and rituals for group bonding. The function of group cohesion around consciousness-altering substances will continue to play an important role in many communities. </p><p>Of course, we should continue to explore the efficacy of psychedelics on anxiety, depression, suicidal ideation, PTSD, and addiction. <a href="https://bigthink.com/surprising-science/antidepressant-effects" target="_self">Pharmacological dependence</a> is a stain on the psychiatry industry. Whether or not psychedelics can be prescribed for daily use remains to be seen, but we know a moneyed interest is expecting a return on investment—the above company, ATAI Life Sciences, raised $157 million in its Series D round. </p><p>When it comes to wellbeing, some things money just can't buy. How we navigate the tricky terrain of mainstreaming psychedelics remains to be seen. </p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a> and <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank" rel="noopener noreferrer">Facebook</a>. His most recent book is</em> "<em><a href="https://www.amazon.com/gp/product/B08KRVMP2M?pf_rd_r=MDJW43337675SZ0X00FH&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee" target="_blank" rel="noopener noreferrer">Hero's Dose: The Case For Psychedelics in Ritual and Therapy</a>."</em></p>
What makes some people more likely to shiver than others?
Some people just aren't bothered by the cold, no matter how low the temperature dips. And the reason for this may be in a person's genes.
A new study finds that dogs fed fresh human-grade food don't need to eat—or do their business—as much.
- Most dogs eat a diet that's primarily kibble.
- When fed a fresh-food diet, however, they don't need to consume as much.
- Dogs on fresh-food diets have healthier gut biomes.
Four diets were tested<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTU5ODI1MS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1NjY0NjIxMn0._w0k-qFOC86AqmtPHJBK_i-9F5oVyVYsYtUrdvfUxWQ/img.jpg?width=980" id="1b1e4" class="rm-shortcode" data-rm-shortcode-id="87937436a81c700a8ab3b1d763354843" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="960" />
Credit: AntonioDiaz/Adobe Stock<p>The researchers tested refrigerated and fresh human-grade foods against kibble, the food most dogs live on. The <a href="https://frontierpets.com.au/blogs/news/how-kibble-or-dry-dog-food-is-made" target="_blank">ingredients</a> of kibble are mashed into a dough and then extruded, forced through a die of some kind into the desired shape — think a <a href="https://en.wikipedia.org/wiki/Food_extrusion" target="_blank">pasta maker</a>. The resulting pellets are sprayed with additional flavor and color.</p><p>For four weeks, researchers fed 12 beagles one of four diets:</p><ol><li>a extruded diet — Blue Buffalo Chicken and Brown Rice Recipe</li><li>a fresh refrigerated diet — Freshpet Roasted Meals Tender Chicken Recipe</li><li>a fresh diet — JustFoodforDogs Beef & Russet Potato Recipe</li><li>another fresh diet — JustFoodforDogs Chicken & White Rice Recipe.</li></ol><p>The two fresh diets contained minimally processed beef, chicken, broccoli, rice, carrots, and various food chunks in a canine casserole of sorts. </p><p>(One can't help but think how hard it would be to get finicky cats to test new diets. As if.)</p><p>Senior author <a href="https://ansc.illinois.edu/directory/ksswanso" target="_blank" rel="noopener noreferrer">Kelly S. Swanson</a> of U of I's Department of Animal Sciences and the Division of Nutritional Sciences, was a bit surprised at how much better dogs did on people food than even refrigerated dog chow. "Based on past research we've conducted I'm not surprised with the results when feeding human-grade compared to an extruded dry diet," he <a href="https://aces.illinois.edu/news/feed-fido-fresh-human-grade-dog-food-scoop-less-poop" target="_blank">says</a>, adding, "However, I did not expect to see how well the human-grade fresh food performed, even compared to a fresh commercial processed brand."</p>
Tracking the effect of each diet<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNTU5ODI1OC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY3NjY1NTgyOX0.AdyMb8OEcjCD6iWYnXjToDmcnjfTSn-0-dfG96SIpUA/img.jpg?width=980" id="da892" class="rm-shortcode" data-rm-shortcode-id="880d952420679aeccd1eaf32b5339810" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="960" />
Credit: Patryk Kosmider/Adobe Stock<p>The researchers tracked the dogs' weights and analyzed the microbiota in their fecal matter.</p><p>It turned out that the dogs on kibble had to eat more to maintain their body weight. This resulted in their producing 1.5 to 2.9 times the amount of poop produced by dogs on the fresh diets.</p><p>Says Swanson, "This is consistent with a 2019 National Institute of Health study in humans that found people eating a fresh whole food diet consumed on average 500 less calories per day, and reported being more satisfied, than people eating a more processed diet."</p><p>Maybe even more interesting was the effect of fresh food on the gut biome. Though there remains much we don't yet know about microbiota, it was nonetheless the case that the microbial communities found in fresh-food poo was different.</p><p>"Because a healthy gut means a healthy mutt," says Swanson, "fecal microbial and metabolite profiles are important readouts of diet assessment. As we have shown in <a href="https://academic.oup.com/jas/article/92/9/3781/4702209#110855647" target="_blank">previous studies</a>, the fecal microbial communities of healthy dogs fed fresh diets were different than those fed kibble. These unique microbial profiles were likely due to differences in diet processing, ingredient source, and the concentration and type of dietary fibers, proteins, and fats that are known to influence what is digested by the dog and what reaches the colon for fermentation."</p>
How did kibble take over canine diets?<p>Historically, dogs ate scraps left over by humans. It has only been <a href="https://www.thefarmersdog.com/digest/the-history-of-commercial-pet-food-a-great-american-marketing-story/" target="_blank">since 1870</a>, with the arrival of the luxe Spratt's Meat Fibrine Dog Cakes—made from "the dried unsalted gelatinous parts of Prairie Beef", mmm—that commercial dog food began to take hold. Dog bone-shaped biscuits first appeared in 1907. Ken-L Ration dates from 1922. Kibble was first extruded in 1956. Pet food had become a great way to turn <a href="https://www.dogfoodadvisor.com/choosing-dog-food/animal-by-products/" target="_blank">human-food waste</a> into profit.</p><p>Commercial dog food became the norm for most household canines only after a massive marketing campaign led by a group of dog-food industry lobbyists called the Pet Food Institute in 1964. Over time, for most households, dog food was what dogs ate — what else? Human food? These days more than half of U.S. dogs are <a href="https://www.nytimes.com/2014/08/03/magazine/who-made-that-dog-biscuit.html" target="_blank">overweight or obese</a>, and certainly their diet is a factor.<span></span></p><p>We're not so special among animals after all. If something's healthy for us to eat—we're <em>not</em> looking at you, chocolate—maybe we should remember to share with our canine compatriots. Not from the table, though.</p>
Eating veggies is good for you. Now we can stop debating how much we should eat.
- A massive new study confirms that five servings of fruit and veggies a day can lower the risk of death.
- The maximum benefit is found at two servings of fruit and three of veggies—anything more offers no extra benefit according to the researchers.
- Not all fruits and veggies are equal. Leafy greens are better for you than starchy corn and potatoes.