mind as the instrument. The commonest way that has been used to find out the relative
intellectual level of creatures at different stage of evolutionary complexity has been to 【M2】______
study the way they behave when giving different kinds of puzzles. For example, an ant 【M3】______
possesses a complex routine of behaviour, but can it think？ The answer is what if an ant is 【M4】______
forced to go through a maze of passages; many of which are dead ends, on its way to its
nestle, it starts by making a lot of mistakes and taking a great many wrong turnings. In the 【M5】______
end, however, after it has to worry its way through often enough, it does learn to get to its 【M6】______
nest without going into any of the blind alleys. As one moves up the evolutionary scale the
test of mind-power exemplified by solving the problem of getting through a maze be 【M7】______
comes very simple. Among mammals, for example, the maze is an inadequate test. The 【M8】______
learning problem does not tax enough attributes of the mind. In this sort of learning, as a
matter of fact, rats can hit university undergraduates and have, in fact, repeatedly done so. 【M9】______
The next, more subtle test of mental ability is to see what level an animal can think about 【M10】______
something when it is not there.
【M1】