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The Dead Man's Switch

Last night's LOST season finale made mention of a "Dead Man's Trigger," which is another term for a Dead Man's Switch. Although these devices are well known to some geeks, I thought I'd write a little explainer to introduce the notion more broadly. (Warning: very minor LOST spoilers follow.) While the LOST switch was in fact a "fail-deadly" (the opposite of a fail-safe), the concept is similar. In fact, this isn't the first time we've seen a Dead Man's Switch on LOST: Season 2 was all about Desmond's switch.

The Dead Man's Switch is generally a fail-safe device intended to take action if a human fails to routinely activate it -- in other words, if the human dies, the switch goes off, and something happens.

Historically, a Dead Man's Switch was installed in potentially dangerous machinery like locomotives, streetcars, and subways. The switch itself could take many forms, though typically it was a handle of some sort that needed to be operated by the user. By forcing the human operator of these machines to occasionally (or even continuously) activate the switch, you could (theoretically) ensure that the machine would shut down if the operator was dead, incapacitated, or missing. Common mechanical Dead Man's Switches exist in New York subways and even lawnmowers and tractors. Here's a snippet from Wikipedia:

In many modern New York Subway trains, for example, the dead man's switch is incorporated into the train's speed control. On the R142A the train operator must continually hold the lever in place. This was depicted in the movie and book The Taking of Pelham 123, in which a group of men hijack a New York City subway train for ransom, but because of the Dead-man's feature, cannot escape while the train is moving.

Every lawn mower sold in the US since 1982 has an "operator-presence" device, which by law must stop the blades within 3 seconds after the user lets go of the controls.

Many modern systems could benefit from a Dead Man's Switch. For example, typical automative Cruise Control systems don't have such a switch, which could allow a vehicle to effectively drive itself after the user falls asleep. Of course, this doesn't last long, as the vehicle hits something sooner or later -- but wouldn't a better failure mode be to slow down rather than keep going?

In high tech, ubergeeks have been using Dead Man's Switches to protect their data or implement disaster-containment protocols in case something goes terribly wrong. If you're a political dissident or involved in something else potentially dicey, a Dead Man's Switch can be implemented as software, a sort of "nuclear option" that will zap your data -- or contact trusted compatriots -- if you fail to activate it. Slashdot held a discussion entitled What Does Your Dead Man's Switch Do? in 2007, leading to several interesting stories (and tons of off-topic discussion). Here's a good example:

I often take part in political protests, and have on occasion been arrested and held for days.

So, I put together a quick routine using perl and chron that dispatches email to my workplace, the local legal rep contact, and some friends. The later includes directions to a hidden key and asks them to feed my cat until they hear from me. I only enable the system when I'm expecting a significant risk of arrest. Once it's started, if I don't either log into the machine or send myself an email containing a specific string once every 24 hours, the alarm goes off.

The Dead Man's Switch has also appeared in literature; one popular example I can recall is the nuclear trigger on Raven's motorcycle in Neal Stephenson's Snow Crash. But I'm sure there are more examples out there. Have you come across a Dead Man's Switch, in life or in fiction? Share in the comments!

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The Surprising Link Between Language and Depression
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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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The ‘Scully Effect’ Is Real: Female X-Files Fans More Likely to Go Into STEM
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FBI agent Dana Scully is more than just a role model for remaining professional when a colleague won't stop talking about his vast governmental conspiracy theories. The skeptical doctor played by Gillian Anderson on The X-Files helped inspire women to go into STEM (science, technology, engineering, and math) careers, according to a new report [PDF] from the Geena Davis Institute on Gender in Media, which we spotted at Fast Company.

“In the world of entertainment media, where scientists are often portrayed as white men wearing white coats and working alone in labs, Scully stood out in the 1990s as the only female STEM character in a prominent, prime-time television role,” the report explains. Previously, anecdotal evidence has pointed to the existence of a “Scully effect,” in which the measured TV scientist—with her detailed note-taking, evidence-based approach, and desire to autopsy everything—inspired women to seek out their own science careers. This report provides the hard data.

The Geena Davis Institute surveyed more than 2000 women in the U.S. above the age of 25, a significant portion of whom were viewers of The X-Files (68 percent) and women who had studied for or were in STEM careers (49 percent). While the survey didn’t ask women whether watching Dana Scully on The X-Files directly influenced their decision to be a scientist, the results hint that seeing a character like her on TV regularly did affect them. Women who watched more of the show were more likely to say they were interested in STEM, more likely to have studied a STEM field in college, and more likely to have worked in a STEM field after college.

While it’s hard to draw a direct line of causation there—women who are interested in science might just be more inclined to watch a sci-fi show like The X-Files than women who grow up to be historians—viewers also tended to say Scully gave them positive impressions of women in science. More than half of respondents who were familiar with Scully’s character said she increased their confidence in succeeding in a male-dominated profession. More than 60 percent of the respondents said she increased their belief in the importance of STEM. And when asked to describe her, they were most likely to say she was “smart” and “intelligent” before any other adjective.

STEM fields are still overwhelmingly male, and governments, nonprofits, schools, activists, and some tech companies have been pushing to make the field more diverse by recruiting and retaining more female talent. While the desire to become a doctor or an engineer isn’t the only thing keeping STEM a boy’s club, women also need more role models in the fields whose success and accomplishments they can look up to. Even if some of those role models are fictional.

Now that The X-Files has returned to Fox, perhaps Dana Scully will have an opportunity to shepherd a whole new generation of women into the sciences.

[h/t Fast Company]

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