The Republican Brain by is Mooney

much more so than our conscious thoughts. Positive or negative feelings about people, things, and ideas arise in a matter of milliseconds, fast enough to detect with an EEG device but long before we’re aware of it.
    The newer parts of the brain, such as the prefrontal cortex, empower abstract reasoning, language, and more conscious and goal-directed behavior. In general, these operations are slower and only able to focus on a few things or ideas at once. Their bandwidth is limited.
    Thus, while the newer parts of the brain may be responsible for our species’ greatest innovations and insights, it isn’t like they always get to run the show. “There are certain important circumstances where natural selection basically didn’t trust us to make the right choice,” explains Aaron Sell, an evolutionary psychologist at Griffith University in Australia. “We have a highly experimental frontal lobe that plays around with ideas, but there are circumstances, like danger, where we’re not allowed to do that.” Instead, the rapid-fire emotions take control and run an automatic response program—e.g., fight or flight.
    Indeed, according to evolutionary psychologists Leda Cosmides and John Tooby of the University of California-Santa Barbara, the emotions are best thought of as a kind of control system to coordinate brain operations— Matrix- like programs for running all the other programs. And when the control programs kick in, human reason doesn’t necessarily get the option of an override.
    How does this set the stage for motivated reasoning?
    Mirroring this evolutionary account, psychologists have been talking seriously about the “primacy of affect”—emotions preceding, and often trumping, our conscious thoughts—for three decades. Today they broadly break the brain’s actions into the operations of “System 1” and “System 2,” which are roughly analogous to the emotional and the reasoning brain.
    System 1, the older system, governs our rapid fire emotions; System 2 refers to our slower moving, thoughtful, and conscious processing of information. Its operations, however, aren’t necessarily free of emotion or bias. Quite the contrary: System 1 can drive System 2. Before you’re even aware you’re reasoning your emotions may have set you on a course of thinking that’s highly skewed, especially on topics you care a great deal about.
    How do System 1’s biases infiltrate System 2? The mechanism is thought to be memory retrieval—in other words, the thoughts, images, and arguments called into one’s conscious mind following a rapid emotional reaction. Memory, as embodied in the brain, is conceived of as a network, made up of nodes and linkages between them—and what occurs after an emotional reaction is called spreading activation . As you begin to call a subject to mind (like Sarah Palin) from your long-term memory, nodes associated with that subject (“woman,” “Republican,” “Bristol,” “death panels,” “Paul Revere”) are activated in a fanlike pattern—like a fire that races across a landscape but only burns a small fraction of the trees. And subconscious and automatic emotion starts the burn. It therefore determines what the conscious mind has available to work with—to argue with.
    To see how it plays out in practice, consider a conservative Christian who has just heard about a new scientific discovery—a new hominid finding, say, confirming our evolutionary origins—that deeply challenges something he or she believes (“human beings were created by God”; “the book of Genesis is literally true”). What happens next, explains Stony Brook University political scientist Charles Taber, is a subconscious negative (or “affective”) response to the threatening new information—and that response, in turn, guides the type of memories