BoundedRationality_TheAdaptiveToolbox.pdf

58 Peter M. Todd
One-reason Decision Mechanisms
How well can simple decision heuristics perform when multiple pieces of information
are available, and recognition cannot be used? The fastest and simplest
of such heuristics would rely on just a single cue to make a decision — but can
this possibly work? The answer turns out to be yes, so long as the cue to use is itself
chosen properly. Imagine that we again have two objects to compare on
some criterion, and several cues that could be used to assess each object on the
criterion. A one-reason heuristic that makes decisions on the basis of a single cue
could then work as follows (see Figure 4.1): (1) select a cue dimension and look
for the corresponding cue values of each option; (2) compare the two options
with regard to their values for that cue dimension; (3) if they differ, then stop and
choose the option with the cue value indicating a greater value on the choice criterion;
(4) if the options do not differ, then return to the beginning of this loop
(step 1) to look for another cue dimension. Such a heuristic will often have to
No
Select a cue and check cue values of
available alternatives
Does cue discriminate
between alternatives?
Yes
Decide on alternative indicated by
current cue
Figure 4.1 A flowchart of one-reason decision making: (1) a cue dimension is selected,
and the corresponding cue values of each alternative are ascertained; (2) check whether
the values for that cue dimension discriminate between the alternatives; (3) if so, then
choose the indicated alternative; (4) if not, select another cue dimension and repeat this
process. (Random choice can be used if no more cues are available.)