The encoding of ignored information.

An experiment was conducted to study the dimensions of encoding of verbal material in short-term memory as a function of other demands placed on Ss attention. Eighty Ss shadowed one of two simultaneous lists, under instructions to remember the shadowed or the nonshadowed list, A single recognition probe followed each shadowing trial. Ss judged whether the probed item was (1) identical to, (2) a rhyme of, or (3) a synonym of one of the to be remembered items. Results indicated that acoustic information was encoded from all inputs, regardless of the focus of attention. Evidence for semantic encoding, however, was limited to those conditions in which retention of shadowed material was required. The data were interpreted as contradicting "late selection" theories of attention, which propose that all inputs are analyzed for meaning prior to the focusing of attention.