Category: Popular science

5 of the Greatest Physics Demos From the MythBusters

Wired:

What would happen if you shot a ball with a speed of 60 mph from the back a car traveling at 60 mph? Would the ball remain stationary? Yup—that’s exactly what the MythBusters did. That animation is so awesome to watch.

This is all about relative velocity. The speed of the ball with respect to the car is 60 mph to the right (negative) and the speed of the car with respect to the ground is 60 mph to the left (positive). This means that the speed of the ball with respect to the ground is 60 mph + (-60 mph) = 0 mph. The math doesn’t seem so complicated, but getting the relative speeds just right isn’t so simple.

 

Hierarchy is Detrimental for Human Cooperation

Nature:

Studies of animal behavior consistently demonstrate that the social environment impacts cooperation, yet the effect of social dynamics has been largely excluded from studies of human cooperation. Here, we introduce a novel approach inspired by nonhuman primate research to address how social hierarchies impact human cooperation. Participants competed to earn hierarchy positions and then could cooperate with another individual in the hierarchy by investing in a common effort. Cooperation was achieved if the combined investments exceeded a threshold, and the higher ranked individual distributed the spoils unless control was contested by the partner. Compared to a condition lacking hierarchy, cooperation declined in the presence of a hierarchy due to a decrease in investment by lower ranked individuals. Furthermore, hierarchy was detrimental to cooperation regardless of whether it was earned or arbitrary. These findings mirror results from nonhuman primates and demonstrate that hierarchies are detrimental to cooperation. However, these results deviate from nonhuman primate findings by demonstrating that human behavior is responsive to changing hierarchical structures and suggests partnership dynamics that may improve cooperation. This work introduces a controlled way to investigate the social influences on human behavior, and demonstrates the evolutionary continuity of human behavior with other primate species.

 

Why hipsters all look alike

Washington Post:

Jonathan Touboul is a mathematician and a neuroscientist. He holds a PhD in math from France’s prestigious École Polytechnique, where he won a prize for his thesis on how to simulate neurons in the brain. He publishes papers with titles like “Pulsatile localized dynamics in delayed neural-field equations in arbitrary dimension” and “The propagation of chaos in neural fields.”

In recent years, though, Touboul has been thinking about hipsters. Specifically, why hipsters all seem to dress alike. In his line of work, there are neurons that also behave like hipsters. They fire when every neuron around them is quiet; or they fall silent when every neuron around them is chattering.

Because he is a mathematician, Touboul began to look for a way to explore this idea using equations. In other words, he constructed a mathematical model. His key insight is that people (and neurons) do not instantly perceive what is mainstream. There’s a delay. And in situations where the delay is large enough, the contrarians can inadvertently synchronize with each other.

“In wanting to oppose the trends, there actually emerges some sort of hipster loop,” Touboul said.

A day before Halloween, Touboul put a draft of his paper on the arXiv, calling it “The hipster effect: When anticonformists all look the same.

 

Why People Believe Meaningless Bullsh*t

NY Mag:

Summarizing the results, Pennycook, et al., write that “[people] more receptive to bullshit are less reflective, lower in cognitive ability (i.e., verbal and fluid intelligence, numeracy), are more prone to … conspiratorial ideation, are more likely to hold religious and paranormal beliefs, and are more likely to endorse complementary and alternative medicine.”

This makes some degree of intuitive sense — to the extent all these characteristics can be swept under the same umbrella, that umbrella would be marked “not very skeptical.” Those who don’t instinctively question the information presented to them might see a statement like “Each of us gives rise to existential bliss” — yes, I generated that one using wisdomofchopra.com — and think, Whoa, that’s pretty deep. Those who are more skeptical, on the other hand, are more likely to, well, call bullshit.

Where things get really complicated — and less lighthearted — is the question of how beliefs in pseudo-intellectual bullshit relate to beliefs in dangerous or misleading medical or scientific beliefs. It makes sense on its face that someone who believes in the wisdom of Chopra might also be more vulnerable to, say, a viral website propagating an unproven claim about using coconut oil to treat Alzheimer’s, but there’s just no way to know for sure without doing more research.

Pennycook said it’s unclear exactly how to get people to stop believing in pseudo-profound bullshit. “I usually emphasize the importance of critical thinking, but this isn’t a novel insight,” he said in an email. “We can’t do much to increase our intelligence, but we can make an effort to be more reflective about the information that we come across on a day-to-day basis. Naturally, given the sheer quantity of information that we come across nowadays, it might be necessary to be particularly diligent when it comes to things of particular import (e.g., that relate to health and well-being).”

 

Will Quantum Mechanics Swallow Relativity?

Nautil.us:

Basically you can think of the division between the relativity and quantum systems as “smooth” versus “chunky.” In general relativity, events are continuous and deterministic, meaning that every cause matches up to a specific, local effect. In quantum mechanics, events produced by the interaction of subatomic particles happen in jumps (yes, quantum leaps), with probabilistic rather than definite outcomes.

Or, to use another analogy, not smooth vs chunky but analogue vs digital

Think Your Conscious Brain Directs Your Actions? Think Again

Singularity University:

Think your deliberate, guiding, conscious thoughts are in charge of your actions?

Think again.

In a provocative new paper in Behavioral and Brain Sciences, a team led by Dr. Ezequiel Morsella at San Francisco State University came to a startling conclusion: consciousness is no more than a passive machine running one simple algorithm — to serve up what’s already been decided, and take credit for the decision.

Rather than a sage conductor, it’s just a tiny part of what happens in the brain that makes us “aware.” All the real work goes on under the hood — in our unconscious minds.

The Passive Frame Theory, as Morsella calls it, is based on decades of experimental data observing how people perceive and generate motor responses to odors. It’s not about perception (“I smell a skunk”), but about response (running from a skunk). The key to cracking what consciousness does in the brain is to work backwards from an observable physical action, explains Morsella in his paper.

Why Are Dogs So Insanely Happy to See Us When We Get Home?

io9:

“The separation from the owner for the dog is not voluntary,” says Vallortigara. “It is always unnatural for a dog to detach and abandon the pack.”  Dogs will sometimes go solo on a temporary basis if they’re sufficiently motivated to do so, but they do it knowing that social contact can be resumed at virtually any time.  “The exaggerated level of greeting that can be observed in some dogs is likely due to the fact that they have not yet learned to accept the possibility of non-voluntary detachment,” says Vallortigara.  When trying to appreciate a dog’s over-the-top greeting, Hekman says we need to imagine what it was like for a dog to be alone all day while we were gone.

“This dog probably had a pretty boring day without much enrichment, and moreover may have been alone all day, which is unpleasant for a social animal,” she told io9. “So in addition to being glad to see us, they are probably feeling some relief that they will get to do something interesting, like go for a walk, and have someone else around. Some people are able to have a dog walker come in or send their dogs to daycare—this is a great solution to what can otherwise be a difficult lifestyle for a dog.”

And as Berns points out, the greeting ritual is a social bonding mechanism—but it’s also a function of curiosity.

“When they jump up, they’re trying to lick you in the face,” says Berns. “Part of that is a social greeting, but they’re also trying to taste and smell you to figure out where you’ve been and what you’ve done during the day. So some of it is curiosity. If I’ve been with other dogs, for instance, my dogs know it, and they resort to sniffing intensely.”

Why Red Means Red in Almost Every Language

Nautilus:

When Paul Kay, then an anthropology graduate student at Harvard University, arrived in Tahiti in 1959 to study island life, he expected to have a hard time learning the local words for colors. His field had long espoused a theory called linguistic relativity, which held that language shapes perception. Color was the “parade example,” Kay says. His professors and textbooks taught that people could only recognize a color as categorically distinct from others if they had a word for it. If you knew only three color words, a rainbow would have only three stripes. Blue wouldn’t stand out as blue if you couldn’t name it.

What’s more, according to the relativist view, color categories were arbitrary. The spectrum of color has no intrinsic organization. Scientists had no reason to suspect that cultures divvied it up in similar ways. To an English speaker like Kay, the category “red” might include shades ranging from deep wine to light ruby. But to Tahitians, maybe “red” also included shades that Kay would call “orange” or “purple.” Or maybe Tahitians chunked colors not by a combination of hue, lightness and saturation, as Americans do, but by material qualities, like texture or sheen.

To his surprise, however, Kay found it easy to understand colors in Tahitian. The language had fewer color terms than English. For example, only one word, ninamu, translated to both green and blue (now known as grue). But most Tahitian colors mapped astonishingly well to categories that Kay already knew intuitively, including white, black, red, and yellow. It was strange, he thought, that the groupings weren’t more random.