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Why Does the Sound of Running Water Make You Have to Pee?

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Reader Bill wrote in to ask, “Why does the sound of running water make me want to pee—and sometimes badly?”

The quirk behind the burning need to pee when we hear rainstorms, waterfalls and babbling brooks seems to be all tied up in the power of suggestion.

Most of you are familiar with the name Pavlov, and know that he had something to do with dogs. That something is an experiment where the Russian doctor showed that autonomic responses (visceral reflexes that occur automatically and unconsciously under the control of the autonomic nervous system) could be triggered by outside stimuli.

Dog owners will attest that when a pooch gets its mouth on a piece of meat, they usually produce a river of saliva. In his experiment, Pavlov give dogs some meat powder, which caused them to salivate, right after ringing a bell. After months of repetition, he was able to ring the bell without any meat powder in sight, and the dogs would salivate because they’d been conditioned to associate the bell with food. For another example of classical conditioning in action, see this clip from The Office.

Pavlov thought that a lot of this automatic and unconscious learning happens all the time to people, and you can probably think of a few cases from your own life where you reflexively react a certain way to a seemingly unrelated stimulus. Having to pee at the sound of running water appears to be the same sort of conditioned response. The sound of running water not only mimics the sound of urination itself to create a Pavlovian association, but flushing and washing one's hands also produce that same sound and are closely associated with urinating and further strengthen the connection.

The catch is that this is just hypothetical right now. While many urologists and psychologists think that this is what’s happening, and have said as much in venues like The New England Journal of Medicine, there hasn’t been to my knowledge any published, peer-reviewed research on the underlying reason for the water-pee connection. There’s no denying that it’s there for a lot of people, though, even if we haven’t quite worked out the cause for it.

Plenty of nursing and psychology texts and parenting books advise running water in the sink for situations as varied as potty-training toddlers, helping people with paruresis (shy bladder), and patients fresh out of prostate surgery, who all may have trouble getting the waterworks started unassisted. In the early 1970s, one hospital in New York even gave select patients a tape recorder with headphones and a 30-minute tape of water sounds to ease their bathroom experience. The “audio catheter,” as it was dubbed, made a real splash with the patients and was a huge success.

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Big Questions
How Does Autopilot Work on an Airplane?
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How does autopilot work on an airplane?

Joe Shelton:

David Micklewhyte’s answer is a good one. There are essentially a few types of features that different autopilots have. Some autopilots only have some of these features, while the more powerful autopilots do it all.

  • Heading Hold: There’s a small indicator that the pilot can set on the desired heading and the airplane will fly that heading. This feature doesn’t take the need for wind correction to desired routing into account; that’s left to the pilot.
  • Heading and Navigation: In addition to holding a heading, this version will take an electronic navigation input (e.g. GPS or VOR) and will follow (fly) that navigation reference. It’s sort of like an automated car in that it follows the navigator’s input and the pilot monitors.
  • Altitude Hold: Again, in addition to the above, a desired altitude can be set and the aircraft will fly at that altitude. Some autopilots have the capability for the pilot to select a desired altitude and a climb or descent rate and the aircraft will automatically climb or descend to that altitude and then hold the altitude.
  • Instrument Approaches: Autopilots with this capability will fly preprogrammed instrument approaches to the point where the pilot either takes control and lands or has the autopilot execute a missed approach.

The autopilot is a powerful computer that takes input from either the pilot or a navigation device and essentially does what it is told to do. GPS navigators, for example, can have a full flight plan entered from departure to destination, and the autopilot will follow the navigator’s guidance.

These are the majority of the controls on the autopilot installed in my airplane:

HDG Knob = Heading knob (Used to set the desired heading)

AP = Autopilot (Pressing this turns the autopilot on)

FD = Flight Director (A form of navigational display that the pilot uses)

HDG = Heading (Tells the autopilot to fly the heading set by the Heading Knob)

NAV = Tells the autopilot to follow the input from the selected navigator

APR = Tells the autopilot to fly the chosen approach

ALT = Tells the autopilot to manage the altitude, controlled by the following:

VS = Vertical Speed (Tells the autopilot to climb or descend at the chosen rate)

Nose UP / Nose DN = Sets the climb/descent rate in feet per minute

FLC = Flight Level Change (An easy manual way to set the autopilot)

ALT Knob = Used to enter the desired altitude

This post originally appeared on Quora. Click here to view.

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Big Questions
What's the Difference Between Vanilla and French Vanilla Ice Cream?
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While you’re browsing the ice cream aisle, you may find yourself wondering, “What’s so French about French vanilla?” The name may sound a little fancier than just plain ol’ “vanilla,” but it has nothing to do with the origin of the vanilla itself. (Vanilla is a tropical plant that grows near the equator.)

The difference comes down to eggs, as The Kitchn explains. You may have already noticed that French vanilla ice cream tends to have a slightly yellow coloring, while plain vanilla ice cream is more white. That’s because the base of French vanilla ice cream has egg yolks added to it.

The eggs give French vanilla ice cream both a smoother consistency and that subtle yellow color. The taste is a little richer and a little more complex than a regular vanilla, which is made with just milk and cream and is sometimes called “Philadelphia-style vanilla” ice cream.

In an interview with NPR’s All Things Considered in 2010—when Baskin-Robbins decided to eliminate French Vanilla from its ice cream lineup—ice cream industry consultant Bruce Tharp noted that French vanilla ice cream may date back to at least colonial times, when Thomas Jefferson and George Washington both used ice cream recipes that included egg yolks.

Jefferson likely acquired his taste for ice cream during the time he spent in France, and served it to his White House guests several times. His family’s ice cream recipe—which calls for six egg yolks per quart of cream—seems to have originated with his French butler.

But everyone already knew to trust the French with their dairy products, right?

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