Richard Feynman and the Connection Machine

Danny Hillis is best known for his Connection Machine, a massively parallel supercomputer that led to breakthroughs in computational science and parallel computing. (It also was the subject of Hillis's book The Connection Machine, which was a highly technical but fascinating version of his thesis paper on parallel computing. If you want the only halfway mind-blowing version, check out The Pattern on the Stone.) Hillis later led R&D at Walt Disney Imagineering, but in my book the Connection Machine was his awesomest project.

The Connection Machine was actually a series of supercomputers, labeled CM-1, CM-2, and so on. A CM-5 (codenamed FROSTBURG) is pictured above left -- originally installed at the National Security Agency, it was used to break codes and is now on display at the National Cryptologic Museum. Looking surprisingly like a classic "movie computer" (one did appear in Jurassic Park), the CM-5 was covered in blinky lights that communicated the status of various processing nodes, and could be used in diagnostics. (So they're useful for something after all....)

Anyway, the point of this blog is that Hillis wrote an essay for Physics Today about physicist Richard Feynman's involvement in the Connection Machine's development -- and now the article is available online via The Long Now Foundation. Hillis's article reveals how Feynman was instrumental in designing the Connection Machine's router, which was key in distributing communications within the massive machine. From the article:

Richard's interest in computing went back to his days at Los Alamos, where he supervised the "computers," that is, the people who operated the mechanical calculators. There he was instrumental in setting up some of the first plug-programmable tabulating machines for physical simulation....

The router of the Connection Machine was the part of the hardware that allowed the processors to communicate. It was a complicated device; by comparison, the processors themselves were simple. Connecting a separate communication wire between each pair of processors was impractical since a million processors would require $10^{12]$ wires. Instead, we planned to connect the processors in a 20-dimensional hypercube so that each processor would only need to talk to 20 others directly. Because many processors had to communicate simultaneously, many messages would contend for the same wires. The router's job was to find a free path through this 20-dimensional traffic jam or, if it couldn't, to hold onto the message in a buffer until a path became free. Our question to Richard Feynman was whether we had allowed enough buffers for the router to operate efficiently.

Read the rest if you're interested in Feynman, math, blinky lights, or just crazy engineering projects. See also: more on the Connection Machine, more on Danny Hillis.

Can You 'Hear' These Silent GIFs?

GIFs are silent—otherwise they wouldn't be GIFs. But some people claim to hear distinct noises accompanying certain clips. Check out the GIF below as an example: Do you hear a boom every time the structure hits the ground? If so, you may belong to the 20 to 30 percent of people who experience "visual-evoked auditory response," also known as vEAR.

Researchers from City University London recently published a paper online on the phenomenon in the journal Cortex, the British Psychological Society's Research Digest reports. For their study, they recruited more than 4000 volunteers and 126 paid participants and showed them 24 five-second video clips. Each clip lacked audio, but when asked how they rated the auditory sensation for each video on a scale of 0 to 5, 20 percent of the paid participants rated at least half the videos a 3 or more. The percentage was even higher for the volunteer group.

You can try out the researchers' survey yourself. It takes about 10 minutes.

The likelihood of visual-evoked auditory response, according to the researchers, directly relates to what the subject is looking at. "Some people hear what they see: Car indicator lights, flashing neon shop signs, and people's movements as they walk may all trigger an auditory sensation," they write in the study.

Images packed with meaning, like two cars colliding, are more likely to trigger the auditory illusion. But even more abstract images can produce the effect if they have high levels of something called "motion energy." Motion energy is what you see in the video above when the structure bounces and the camera shakes. It's why a video of a race car driving straight down a road might have less of an auditory impact than a clip of a flickering abstract pattern.

The researchers categorize vEAR as a type of synesthesia, a brain condition in which people's senses are combined. Those with synesthesia might "see" patterns when music plays or "taste" certain colors. Most synesthesia is rare, affecting just 4 percent of the population, but this new study suggests that "hearing motion synesthesia" is much more prevalent.

[h/t BPS Research Digest]

The Surprising Link Between Language and Depression

Skim through the poems of Sylvia Plath, the lyrics of Kurt Cobain, or posts on an internet forum dedicated to depression, and you'll probably start to see some commonalities. That's because there's a particular way that people with clinical depression communicate, whether they're speaking or writing, and psychologists believe they now understand the link between the two.

According to a recent study published in Clinical Psychological Science, there are certain "markers" in a person's parlance that may point to symptoms of clinical depression. Researchers used automated text analysis methods to comb through large quantities of posts in 63 internet forums with more than 6400 members, searching for certain words and phrases. They also noted average sentence length, grammatical patterns, and other factors.

What researchers found was that a person's use (or overuse) of first-person pronouns can provide some insight into the state of their mental health. People with clinical depression tend to use more first-person singular pronouns, such as "I" and "me," and fewer third-person pronouns, like "they," "he," or "she." As Mohammed Al-Mosaiwi, a Ph.D. candidate in psychology at the University of Reading and the head of the study, writes in a post for IFL Science:

"This pattern of pronoun use suggests people with depression are more focused on themselves, and less connected with others. Researchers have reported that pronouns are actually more reliable in identifying depression than negative emotion words."

What remains unclear, though, is whether people who are more focused on themselves tend to depression, or if depression turns a person's focus on themselves. Perhaps unsurprisingly, people with depression also use more negative descriptors, like "lonely" and "miserable."

But, Al-Mosaiwi notes, it's hardly the most important clue when using language to assess clinical depression. Far better indicators, he says, are the presence of "absolutist words" in a person's speech or writing, such as "always," "constantly," and "completely." When overused, they tend to indicate that someone has a "black-and-white view of the world," Al-Mosaiwi says. An analysis of posts on different internet forums found that absolutist words were 50 percent more prevalent on anxiety and depression forums, and 80 percent more prevalent on suicidal ideation forums.

Researchers hope these types of classifications, supported by computerized methods, will prove more and more beneficial in a clinical setting.

[h/t IFL Science]


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