STRANGE BUT TRUE- Just say no: Lie detectors often lie


Q. True or False: Given the 90 percent accuracy of a polygraph, people who are innocent should have few qualms about taking a "lie detector" test. –J.E. Hoover

A. The actual percentage of those falsely accused by the machine can be much higher than the apparent 10 percent, say Jeffrey Bennett and William Briggs in Using and Understanding Mathematics. Suppose the government gives the test to 1000 applicants for sensitive security jobs, and 990 of these people tell the truth, 10 lie. Now of the 10 liars, 9 fail the test, 1 passes. Of the 990 who tell the truth, the polygraph correctly identifies 90 percent, meaning that 10 percent x 990 = 99 truthtellers fail the test. So the total failing is 9 + 99 = 108, of which only 9 actually lied. The other 99/108, or 91.7 percent, who failed the test were in fact falsely accused of lying! Numbers, of course, will vary case to case, but this is an "astounding result." 

Answer: Definitely false. There should be qualms aplenty!

Q. How did Earth's flowering plants eventually blossom into us? The original "flower power." –J. Mitchell

A. Nice-looking and -smelling flowers lured insects into pollination, fostering a wide array of vegetation that benefitted primates, says botanist William C. Burger in University of Chicago Magazine. Originally insectivores, primates climbed trees to get bugs and as a result developed long arms for reaching.

Flowering plants like avocados– "the richest fleshy fruit in the plant world"– helped draw monkeys into eating fruits, aiding development of bending wrists and fingers for examining the food. Their eyes moved forward for binocular vision to jump from tree to tree, flattening the face, meaning primates could no longer see behind them to escape predators. Group living became imperative, encouraging cooperation and socialization. 

Grasslands expanded, enticing primates out of the forest and into savannahs where herbivores easily grazed. Here too were ready meats for beefing up mother's milk with proteins and nutrients, in turn nourishing bigger infant brains that over time flowered into US. Oh, what a bouquet!

Q. In what parts of the world might you encounter the stickiest, ghastliest summer heat? –K. Ford 

A. Bangkok, Thailand is one tough place to keep your cool, with average highs in the upper '90s and minimums in the lower '80s for six months of the year, says Penn State meteorologist Paul Knight. A simple way to measure the discomfort level is to combine the air temperature (measured in the shade at 1.5 meters above the ground) with the dew point, the temperature where the air becomes so saturated that condensation occurs.

Combined values over 160 are very uncomfortable and 170 is downright oppressive. The lack of ventilation plus other heat sources in a large city such as Bangkok only adds to the stifling atmosphere.

Some of the worst discomfort levels may be found in the southeastern U.S., with its high continental temperatures and very high dew points exacerbated by moisture coming up from the Gulf of Mexico, says University of Missouri atmospheric scientist Anthony Lupo. 

Highest recorded dew points occur in the Middle East, surrounding the Red Sea, Gulf of Aden, and the Persian Gulf, adds Louisiana State University climatologist Barry Keim. Such soaring dew points are common in hot places with vast areas of shallow water that also get heated up. The absolute highest dew point ever measured was 95 F at Dhahran, Saudi Arabia, on July 8, 2003. 

Send strange questions to brothers Bill and Rich at [email protected].