One of the most important results of research into ageing has been to pinpoint the signifi

cance of short-term memory. This faculty is easily (1)_____ as ageing advances. What seems to (2)_____ is that in formation is received by the brain, (3)_____ scans it for meaning in order to decode it at some future time. It looks as if the actual (4)_____ of the short-term memory itself may not change too much (5)_____ age. A young man and a man in his late fifties may (6)_____ be able to remember and repeat a(n) (7)_____ of eight numbers recited to them. But what (8)_____ change is that when the older man is asked to re member anything (9)_____ between the time he is first given the numbers to memorise and the time he is asked to (10)_____ them, he will be much less likely to remember the (11)_____ numbers than the young man. This is because the scanning stage is more easily (12)_____ by other activities in (13)_____ people.

In (14)_____ living one experiences this as a fairly minor (15)_____—a telephone number forgotten while one looks (16)_____ an area code, or the first part of (17)_____ street directions confused with the fast because the last 'turn lefts' and' turn rights' have interfered (18)_____ remembering the first directions. In more formal learning, however, the (19)_____ of short-term memory is more than just a mild social embarrassment. It can be a serious bar to further (20)_____ or indeed to any progress at all.

A．discovered

B．strengthened

C．displayed

D．disturbed