The dual processing model assumes that we think in two ways across several tasks.

These can be understood as intuitive (automatic) thinking and rational (controlled) thinking. Kahneman (2001) called intuitive thinking System 1 thinking. This type of thinking is automatic, fast, and requires little effort. System 1 tends to be our default system of cognition when we are short of time or too tired to give a question a lot of thought.

Thinking in this mode operates below our level of consciousness awareness and is a more instinctive way of processing information and figuring things out. System 1 relies on feelings, intuition, and a toolkit of hidden mental shortcuts to help guide our way through the choices we make, rather than thinking about each one methodically and consciously. Though fast, it is prone to biases. We will explore these biases in the next section on the reliability of cognitive processes.

Kahneman calls rational thinking System 2. System 2 is more analytical and goal-directed thinking and/or requires deliberate effort and time. This type of thinking refers to the processes that kick in when we stop, pay attention, and think. Kahneman describes this as slow thinking. Though slow, it is less prone to biases.

Mamade et al. (2014) aimed to determine if unconscious thought (intuitive and automatic thinking) led to better performance than conscious thought (rational and controlled).

Aims: Determine whether “educated intuition” led doctors to make more accurate estimations about the survival probabilities of patients compared to more deliberate thought.

Type of study: Experiment.

Participants: 86 medical experts and 57 novices selected by purposive sampling from academic and non-academic hospitals and from a university medical centre in the Netherlands between April 2009 and May 2011.

Procedures: The participants were presented with four fictitious medical case histories. The four case histories were presented by computer in the form of statements and clinical test results. Half of the participants were encouraged to engage in conscious thought for four minutes about the patient’s life expectancy. The other half were distracted by performing an anagram task for four minutes. The participants were then asked to estimate the probability that each patient would be alive in 5 years’ time.

Results: There was a significant difference in task performance between the novices and the experts. There was no significant different in accuracy between the conscious and unconscious thinking conditions.

Conclusion: Unconscious, intuitive thought did not lead to better or worse performance compared to deliberate, conscious thought.

The study’s report can be accessed here.