Steve Krause : Blog

Tidal Waves Are Not Tidal

I had not thought about it before, but tidal waves are not tidal.

Tidal forces, which cause normal ocean waves, are from the sun's and moon's gravity. This explains why the cycle of high and low tides is regular—because the orbits and rotations of the sun/earth/moon system are regular.

So, tidal wave should just mean a normal wave. But most people understand tidal wave to mean a gigantic wave, a freak of nature.

The problem is, such waves have nothing to do with tides. They are caused by sudden displacements of ocean water due to earthquakes, volcanoes, or other major disruptions. Thus, scientists prefer the term tsunami to describe one or more massive waves caused by an irregular event.

I had always assumed that tidal wave and tsunami were either equivalent or subtle variants. Now I know, tidal waves are just big misnomers. Thanks to Jacqueline for enlightening me.

Genetic Data's Hammer and Nails

In "Regrow Your Own," the New York Times covers research into regeneration of body parts. If other species like salamanders can regenerate various body parts, can humans be made to do the same?

It's an interesting topic in general, but the part that caught my eye was this:

Regeneration is studied in only a few laboratories. It was not even on the agenda of the research planning meeting held last October by the California Institute of Regenerative Medicine, which was dominated by stem cell biologists.

One reason for this orphan status is that the model animals used by most biologists, like the roundworm, the fruitfly and the mouse, happen to be ones that do not regenerate.

The genetics of regenerating animals, like the salamander, are largely unknown. Hence the process of regeneration has received little attention from research biologists.

Now that's a great example of how, as the saying goes, people with hammers (existing genetic data about a small number of species) only see nails (issues relevant to those small number of species).

Thinking About Eating

Two recent studies about the psychology of eating highlight the subconscious at work. Here is the first, by a professor at the University of Chicago:

Imagine two servings of ice cream, one featuring a five-ounce cup overfilled with seven ounces, the other a ten-ounce cup filled with only eight ounces. Objectively the under-filled serving is better, because it contains more. But a study conducted by Christopher Hsee found that unless these two servings are presented side by side, the seven-ounce serving is actually considered more valuable. Apparently, people do not base their judgment on the amount of ice cream available, which is difficult to evaluate in isolation. Instead, they rely on an easy-to-evaluate cue: whether the serving is overfilled or under-filled. Overfilling evokes positive feelings while under-filling evokes negative feelings, and these feelings dictate people’s evaluations. (from "More is Not Always Better")

The second study shows that people think about eating or drinking more in terms of a food unit (I had a soft drink) than a portion size (it's still a single soft drink, whether it's in a 12-ounce soft drink or a 24-ounce bottle).

In one of their experiments, researchers at the University of Pennsylvania...

...offered a large mixing bowl of [M&Ms candy] at the front desk of the concierge of an apartment building. Below the bowl hung a sign that read "Eat Your Fill" with "please use the spoon to serve yourself" written underneath.

If presented with a small spoon, most passersby would take a single scoop, even though the sign encouraged them to take more. If given a much larger spoon, the subjects would still take a single scoop, even though that one scoop contained much more candy. The subjects were inadvertently eating twice as much candy when the larger scoop happened to be in the bowl.

"It is more than just people afraid of appearing greedy. They didn't know they were being observed," Geier said. "We have a culturally enforced 'consumption norm,' which promotes both the tendency to complete eating a unit and the idea that a single unit is the proper amount to eat." (from "Just How Much Is a Serving of Dip?")