<P>The work of memory researchers Alan Baddeley and Graham Hitch is a prime example of the ways in which good critical thinkers approach questions and the problems they raise. </P><P>In the 1960s, researchers into human memory began to understand memory as comprising not one, but two systems. The first was a short-term system handling information for mere seconds. The second was a long-term system capable of managing information indefinitely. They also discovered, however, that short-term memory was not simply a ¿filing cabinet,¿ as many had thought, but was actively working on cognitive ¿ or mental ¿ tasks. This is how the phrase ¿<EM>working memory</EM>¿ developed. The hypothesis remained unproven, however, presenting Baddeley and Hitch with the problem of working out how to produce definitive evidence that short term memory was a working system that actively manipulated and processed information. </P><P>They responded by designing a series of ten experiments aimed at showing just th