They had to remember which one they'd already pressed and therefore which lever to press next, left or right, in order to receive their reward.

它们不得不记住它们已经按过那些杠杆，下一步需要按哪个，左边或右边的杠杆，以获取它们的奖赏。

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In a series of tests, the rats pressed one lever and were then distracted.

在一系列的试验中，大鼠每按一个杠杆则被分心一次。

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They just pressed the lever.

它们只会去压动杠杆。

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They just pressed the lever.

它们只会去压动杠杆。

耶鲁公开课 - 心理学导论课程节选

Those who remember the debacle of the void race in 1993 might be interested to learn about 1951, when starter Leslie Firth pressed the lever with half the field milling about.

BBC: The Grand National 1839-1955

Once this rat pressed the correct lever, its brain activity was delivered as electrical stimulation into the brain of the second rat - designated the "decoder".

BBC: One rat brain 'talks' to another using electronic link