Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. Perhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?
Tiger beetles are such fast runners that they can capture virtually any nonflying insect. However, when running toward an insect, the beetles intermittently stop, and then, a moment later, resume their attack. erhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
Which of the following, if discovered in experiments using artificially moved prey insects, would support one of the two hypotheses and undermine the other?
(A) When a prey insect is moved directly toward a beetle that has been chasing it, the beetle immediately turns and runs away without its usual intermittent stopping. (B) In pursuing a moving insect, the beetles usually respond immediately to changes in the insect's direction, and pause equally frequently whether the chase is up or down an incline. (C) The beetles maintain a fixed time interval between pauses, although when an insect that had been stationary begins to flee, the beetle increases its speed after its next pause. (D) If, when a beetle pauses, it has not gained on the insect it is pursuing, the beetle generally ends its pursuit. (E) When an obstacle is suddenly introduced just in front of running beetles, the beetles sometimes stop immediately, but they never respond by running around the barrier.
C 选项 support：they cannot maintain their pace and must pause for a moment's rest undermine： running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
E选项有些迷惑性，看似在支持第二个hypothese， 但是第二个假设的前提是 beetles are unable to process the resulting rapidly changing visual information，是说chased 对象 在突然改变奔跑方向时，beetles 会突然失去视觉 ，因此 stop，然后又接着继续跑，但是E选项说突然而来的障碍物让beetles 会停顿下来，但是 they never respond by running around the barrier.这个never respond 就与第二个假设有冲突了，因为beetles 的失去视觉是暂时的，所以不会 never respond。
c says that they will stop in the same time period, so support 1 which is can not maintain high speed, the same period undermine the 2; the 2 said the beetles stop to change the direction, but there is no reason to believe the animal that beetles is chasing change direction in the same period, so undermine the second. Moreover, c says the beetles speed up after rest, support the 1
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发表于 2011-6-17 23:21:14
erhaps they cannot maintain their pace and must pause for a moment's rest; but an alternative hypothesis is that while running tiger beetles are unable to process the resulting rapidly changing visual information, and so quickly go blind and stop.
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