A Dual Process Theory is the term for theories that provide two explanations for how a phenomenon occurs. In Mental Construction the phenomenon is reasoning. The two explanations it offers are reasoning by logical and by similarity.
In discussions of brain processing, an additional aspect of the Dual Process Theory is that the two methods – logic and similarity – go on simultaneously.
Is it insane to claim you might being thinking two separate strands of thought at the same time? The idea might be wrong, but it’d be crazy not to consider it when there is support for it. For a little example, consider when you’re driving. You’re making decisions to slow down, to speed up, to turn right or not, and don’t you also find thoughts of yesterday and plans for tomorrow flowing through your brain? Now some might argue this is really rapid multitasking. Maybe when all the evidence is in, that will be the result, but there are physical reasons to suspect the threads of thought in our mind go on independent of one another.
The left-right dichotomy may be asserted too dogmatically in casual conversation, but there is no doubt that certain mental operations are separated to preferred regions of our brain. The two hemispheres and various lobes in a properly working brain exchange information at a fundamental level.
Daniel Kahneman focused on the overt results of a Dual Process explaining our behaviors in Thinking, Fast and Slow. Keith Stanovich presents a more formal discussion and explication of Dual Process Theory as a backdrop in his discussion of What Intelligence Tests Miss – the psychology of rational thought. Check the Works Cited for publishing information on their books.
Logic and Similarity, A New Dual Process Theory presents a nice introduction to the Mental Construction viewpoint.