Research Roundup

Weight loss

Lose the diet to lose the weight

Most dieters will tell you that cutting calories and monitoring meals can be incredibly stressful, says A. Janet Tomiyama, PhD, a postdoctoral student at the University of California, San Francisco, and the University of California, Berkeley. According to Tomiyama's research, such stress may actually work against dieters. "With enough stress, a diet can become counterproductive," she says.

Tomiyama split 121 women into four groups: One counted calories, another ate low-calorie food Tomiyama provided, a third group did both, and the control group ate normally. For two days before and after the three-week experiment, Tomiyama monitored the participants' levels of perceived stress and their cortisol levels — a stress hormone that can cause weight gain and increase the risk of diabetes and obesity.

The calorie-counters reported high stress levels, and the participants on the low-calorie meal plan showed an increase in cortisol production. The participants in the combined condition showed both effects, Tomiyama found.

The results dovetail with many other studies to suggest that dieting isn't a good weight-loss strategy, says Tomiyama. "What people really need are healthy meals combined with exercise. You can count calories all you want and eat as many rice cakes as you want, but it's probably going to hurt more than it helps."

Vertical layouts are the most legible

When people search their visual field — whether it's flipping through iPhone apps or operating an airplane control panel — they can more quickly and accurately find what they're looking for when items are arrayed vertically rather than horizontally, according to research by Joshua Edler, a perception psychology graduate student at Colorado State University in Fort Collins.

In a series of experiments published in Visual Cognition (Vol. 18, No. 1), Edler and colleagues examined whether a target stands out more if it is asymmetrical along the vertical or the horizontal axis. The researchers showed participants assortments of divided two-tone circles; in one experiment, the circles were divided into left and right halves; in another experiment they were divided into upper and lower halves.

All the circles in the field looked the same except for the occasional odd circle whose pattern would be reversed (left black and right white when the rest were right black and left white, for example). The researchers measured how long it took the participants to determine whether an odd circle was present. They found that participants consistently did this more quickly when the circles were split horizontally — up to a second faster when participants had to search through 22 such circles.

That fits with previous research showing that humans have an easier time differentiating between up-down than left-right, Edler says. "Think about learning your left from your right when you were young — it's a little bit tricky," he says. "But almost nobody has problems learning up-down."

That suggests that designers should arrange important instrument controls and scrolling touch-screen displays vertically to make it easier for users to operate, Edler says.