Intuition and Deliberation, One Process or Two?

heartindexThis post examines: “How distinct are intuition and deliberation? An eye-tracking analysis of instruction-induced decision modes,” written by Nina Horstmann, Andrea Ahlgrimm, and Andreas Glöckner that appeared in the August, 2009, Judgment and Decision Making. A long tradition of dual-process models postulates a clear distinction between intuition and deliberation. As Kahneman’s book title pointed out dual-process models differ, but all include Thinking Fast and Slow. By 1980 Hammond (post Cognitive Continuum) had already suggested that intuition and deliberation are not completely distinct categories of cognitive processes between which people switch. Rather, they are seen as poles of a cognitive continuum, and task factors influence how far one moves toward one or the other pole.

In the present paper, the researchers used eye-tracking technology to analyze, on a fine-grained level, how the instruction to decide intuitively or deliberately affects information search and integration.  They then tried to determine whether this favors distinct dual process theories-two systems and two algorithms– or more integrated systems like parallel constraint satisfaction that assume intuitive automatic processing begins every decision. A core assumption of that model is that people can integrate a multitude of information in a weighted compensatory manner within a short time frame due to automatic-intuitive processes. However, these automatic intuitive processes can be supervised and modified by additional operations of the deliberate system.



The experiments comprised  probabilistic inferences where participants were asked to decide which of two cities has more inhabitants, on the basis of probabilistic cues such as the existence(+) or non-existence(-) of an airport, first-league soccer team, etc. Figure 2, above, shows generally how these were set up for view.

Eye-tracking is a less intrusive alternative to record information search. Moreover, and critically, eye-tracking records single fixation durations. (By the way, saccades are quick movements of the eye.)  The authors found that fixation duration is a reliable parameter for levels of processing, for the probabilistic inference (city size cues) tasks that were employed. According to the distinct processes (separate dual processes) assumption, intuition should be based on less controlled, fast information integration processes. In contrast, in a hypothetical pure deliberate decision mode, information is likely to be investigated in a serial, stepwise manner.

Following the integrated processes (integrated dual process or single process) assumption, a primacy of intuitive processes is assumed which are always activated as a default mode. Accordingly, there is not necessarily a clear distinction between decision behavior if individuals are instructed to use one or the other mode. Intuitive processes of quick information search and automatic scanning are always activated in advance and/or simultaneously, and they are only supplemented by additional deliberate processes.

In Study 1, they manipulated the decision mode by using different instructions in simple and complex city-size tasks (Part 1), and in complex legal inference tasks (Part 2). Thus, they captured a somewhat artificial as well as a more content-rich setting. In Study 2, they extended their analysis to a within-participants design, in which additionally  the stability of the effects induced by decision mode instructions was tested.

Altogether, their findings indicate that the instruction to deliberate does not induce qualitatively different information processing compared to instructions to decide intuitively. They consider the results to be in line with the integrated processes assumption. In both studies, mean single fixation duration and the distribution of short, medium and long fixations did not differ between the intuitive and the deliberate decision mode. According to Horstmann et al the dominance of short and medium fixations indicates that quick information scanning prevails over the entire decision process. In contrast to a pattern of particularly long fixations observed under the instruction to consciously calculate weighted sums. even under the deliberate
instruction long fixations that point to a calculation or rule-based, thorough, slow and serial information integration were rarely found. Hence, the findings suggest a very similar basic process underlying intuitive and deliberate decisions, namely an automatic process of information integration.

Nevertheless, the researchers found some crucial differences regarding intuition and deliberation. A higher number of fixations caused by a higher amount of inspected information and more repeated information inspections under the instruction to deliberate reveal that the basic process of automatic information integration is supplemented by additional processing steps. Hence, deliberation seems to be associated with a more thorough and extensive information search.  They argue that instruction-induced deliberation is not necessarily a completely serial, stepwise and rule-based process. However, relatively short decision times and the dominance of short and medium fixation durations indicate that even participants deciding deliberately do not apply conscious calculations. These findings are in line with
process analyses of decisions under risk showing that expected-value choices rarely result from deliberate calculations of weighted sums.

Three caveats of the study were noted by the authors:

  1. It is possible that instructions cannot be used to induce distinct processes efficiently, or that processes are in fact integrated. Further research is, however, necessary to investigate this question more thoroughly.
  2. Observations in the two parts were not strictly independent due to sample size restraints, thus lowering the validity of the within-participants replication of the effects for different material.
  3. It is not unlikely that the results are partially dependent on the specific wording of the instruction. It has to be shown in future studies whether our findings also hold for instructions which highlight other aspects of deliberation (e.g., to think carefully and thoroughly).

A crucial finding of Study 2 was that deliberate instructions induced stable effects over different test times. In contrast, intuitive instructions seem to be less stable over repeated measurements, possibly due to training effects. In conclusion, intuition and deliberation do not seem to be completely distinct processes. To account for the underlying processes of intuitive and deliberate decision making, models that postulate a common underlying process
such as a parallel constraint satisfaction mechanism seem to be more suitable. Overall, according to the authors the reported experiments add to the accumulating body of evidence that automatic information integration plays a crucial role in decision making, independent
of whether people decide intuitively or deliberately. Eyetracking technology seems to be a promising approach to investigate these automatic processes.

I should note that this paper indicates the primacy of intuitive automatic processes which seems to differ from Hammond’s idea that quasi-rationality is where decisions begin. My interpretation is, of course, suspect.

Nina Horstmann, Andrea Ahlgrimm, and Andreas Glöckner that appeared in the August, 2009, Judgment and Decision Making, Vol. 4, No. 5, August 2009, pp. 335–354

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