There is a certain novelty to implicit attitudes. The notion that people possess unspoken thoughts that can shape their judgments without their control is patently at odds with conventional wisdom about the deliberative and intentional nature of human reasoning (e.g., Bargh 2007: 1; Greenwald and Banaji 1995: 4; Taber 2003: 462). But novelty is not enough to carry a concept forward in political science. Without a detailed understanding about what implicit attitudes are, why they emerge, and what characteristics they display, the idea of implicit attitudes can easily become vacuous. Heavy conceptual lifting is therefore required before we even begin assembling a theoretical framework to explain the influence of implicit attitudes in the realm of immigration politics. Such is the goal of this chapter.

To this end, I begin by discussing and explaining social psychologists’ (and a few political psychologists’) changing views about human memory and reasoning. Here, researchers are increasingly learning that human thinking is organized into two systems, or forms, of reasoning that vary in terms of how they process and utilize information (e.g., Deutsch and Strack 2010; Gawronski and Bodenhausen 2011; Giner-Sorolla 2012; Haidt 2012; Kahneman 2011; Leander and Chartrand 2011; Lodge and Taber 2013; Rydell and McConnell 2006; Sloman 1996; Smith and DeCoster 2000). Each of these two systems operates under different rationales and by way of distinct cognitive principles. Whereas one system of reasoning is more conducive to the deliberative and controlled type of thinking that many political scientists are familiar with, the other form of reasoning facilitates more spontaneous and impulsive forms of thought. And, although many political scientists often think of deliberative thinking as primary (if not singular), research suggests people's impulsive reasoning often precedes their more deliberative cognitive efforts (e.g., Gawronski and Bodenhausen 2011; Lodge and Taber 2013; Olson and Fazio 2009).

Building on this difference between forms of thinking, I then explain the types of attitudes produced by each cognitive system, namely, explicit and implicit attitudes. Because explicit and implicit attitudes emanate from distinct reasoning systems, each type of attitude differs in its underlying substance and mode of operation (e.g., Rydell and McConnell 2006; Smith and DeCoster 2000; Wilson et al. 2000). Thus, for example, explicit attitudes reflect one's more considered thoughts; they enter one's judgments at the discretion of individuals (e.g., Gawronski and Bodenhausen 2006; Strack and Deutsch 2004).