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C impact of sensor networks on power supply
D elimination of batteries in sensor networks
54. Wireless sensor networks promise to ____.
A bring businesses high profits
B further develop the sensing technology
C improve the daily lives of people worldwide
D turn motion into a major source of energy
Passage Five
In the early 20th century, a horse named Clever Hans was believed capable of counting and other impressive mental tasks. After years of great performance, psychologists discovered that though Hans was certainly clever, he was not clever in the way everyone expected. The horse was cleverly picking up on tiny, unintentional bodily and facial signals given out not only by his trainer, but also by the audience. Aware of the “Clever Hans” effect, Lisa Lit at the University of California and her colleagues wondered whether the beliefs of professional dog handlers might similarly affect the outcomes of searchers for drugs and explosives. Remarkably, Dr Lit found, they do.
Dr Lit asked 18 professional dog handlers and their dogs to complete brief searches. Before the searches, the handlers were informed that some of the search area might contain up to three target scents, and also that in two cases those scents would be marked by pieces of red paper. What the handlers were not told was that none of the search areas contained the scents of either drugs or explosives. Any “detections” made by the teams thus had to be false.
The findings reveals that of 144 searches, only 21 were clean (no alerts). All the others raised one alert or more. In total, the teams raised 225 alerts. While the sheer number of false alerts stuck Dr Lit as fascinating, it was where they took place that was of greatest interest.
When handlers could see a red piece of paper, allegedly marking a location of interest, they were much more likely to say that their dogs signaled an alert. The human handlers were not only distracted on almost every occasion by the stimulus aimed at them, but also transmitted that distraction to their animals—who responded accordingly. To mix metaphors, the dogs were crying “wolf” at the unconscious signal of their handlers.
How much that matters in the real world is unclear. But it might. If a handler, for example, unconsciously “profiled” people being sniffed by a drug, or explosive-detecting dog at an airport, false positive could abound. That is not only bad for innocent travelers, but might distract the team from catching the guilty.
55. What did psychologists find out about Clever Hans?
A He was as clever as people claimed.
B He was really good at counting.
C He merely responded to human signals.
D He could understand human language.
56. Lisa Lit and her colleagues ____.
A questioned the “Clever Hans” effect
B discovered the “Clever Hans” effect
C rejected the “Clever Hans” effect
D confirmed the “Clever Hans” effect
57. The dog handlers learned before the searches that ____. |
