Daniel Khaneman in his book Thinking Fast and Slow (2011) outlines two systems, originally proposed by Stanovich and West (2000) (Dual Systems Approach), used for judgements, reasoning, and decision making.  System 1 (Type One Processing) is fast, automatic, nonconscious,  intuitive and more efficient by engaging less cognitive resources,  but is also the system responsible for errors caused by biases, heuristics, and influenced by emotions.  System Two (Type Two Processing) is reflective, slow, conscious, and controlled processing that can intervene and override System One.  Less errors occur when System Two is engaged, but is costly in cognitive resources.  The Wason four-card tasks demonstrates the difference in systems within two types of the task.  One abstract version that utilizes leterna dn numbers requires effortful, thoughtful reasoning and engages System Two.  The other version uses beer and drinking age, which is a more realistic scenario, and consequently engages System One to solve the problem.  

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