items retained in memory (see below in Resource theories), with some items in the focus of attention being allocated more resource and recalled with greater precision.

Whereas most adults can repeat about seven digits in correct order, some individuals have shown impressive enlargements of their digit span--up to 80 digits. This feat is possible by extensive training on an encoding strategy by which the digits in a list are grouped (usually in groups of three to five) and these groups are encoded as a single unit (a chunk). For this to