was to identify target items consisting of members of a designated category.
The targets were ambiguous words having at least two distinct meanings. For
example, if the category were ‘‘articles of clothing,’’ then ‘‘socks’’ would be a
possible target word. Each target word was accompanied by a non-target word
biasing the appropriate meaning of the target (e.g. ‘‘smelly’’), or a non-target
word biasing the inappropriate meaning (e.g. ‘‘punches’’), or by a neutral non-
target word (e.g. ‘‘Tuesday’’).
When subjects did not know which ear targets would arrive at (divided
attention), appropriate non-targets facilitated the detection of targets and in-
appropriate non-targets impaired performance (see figure 15.3). Thus, when
attention needed to be divided between the two ears, there was clear evidence
that the non-target words were processed for meaning. On the other hand,
when subjects knew that all the targets would be presented to the left ear, the
type of non-target word presented at the same time had no effect on target de-
tection. This suggests that non-targets were not processed for meaning in this
focused attention condition, and that the amount of processing received by
non-targetstimuliisonlyasmuchasisnecessarytoperformtheexperimental
task.
Section Summary
The analysis of unattended auditory inputs can be greater than was originally
thought. However, the full analysis theory of Deutsch and Deutsch (1963)
seems rather dubious in view of the findings obtained by Treisman and Geffen
(1967) and Treisman and Riley (1969). The most reasonable account of focused
attention may be along the lines suggested by Treisman (1964), with reduced or
attenuated processing of sources of information outside focal attention. The
extent of such processing is probably flexible, being determined in part by task
demands (Johnston & Heinz, 1978).
Figure 15.3
Effects of attention condition (divided vs. focused) and of type of non-target on target detection.
Data from Johnston and Wilson (1980).
Attention and Performance Limitations 369