The power of emotions to influence judgment, including political attitudes, has been recognized since classical antiquity.
Aristotle, in his treatise
Rhetoric, described emotional arousal as critical to persuasion, "The orator persuades by means of his hearers, when they are roused to emotion by his speech; for the judgments we deliver are not the same when we are influenced by joy or sorrow, love or hate." Aristotle warned that emotions may create beliefs where none existed, or change existing beliefs, and may enhance or decrease the strength with which a belief is held.
Seneca, in the first century CE, similarly warned that "Reason herself, to whom the reins of power have been entrusted, remains mistress only so long as she is kept apart from the passions."'''' In the 17th century, French scientist and philosopher,
Blaise Pascal wrote that "People [...] arrive at their beliefs not on the basis of
proof, but on the basis of what they find attractive."
Baruch Spinoza characterized emotions as having the power to "make the mind inclined to think one thing rather than another." Disagreeing with
Seneca the Younger that emotion destroys reason, the 18th century Scottish philosopher
George Campbell argued, instead, that emotions were allies of reason, and that they aid in the assimilation of knowledge. However, Campbell warned of the malleability of emotion and the consequent risk in terms of suggestibility: ::[Emotions] are not supplanters of reason, or even rivals in her sway; they are her handmaids, by whose ministry she is enabled to usher truth into the heart, and procure it to favorable reception. As handmaids, they are liable to be seduced by sophistry in the garb of reason, and sometimes are made ignorantly to lend their aid in the introduction of falsehood. Propaganda theorist
Edward Bernays asserted confidently that "in certain cases we can effect some change in public opinion with a fair degree of accuracy by operating a certain mechanism, just as a motorist can regulate the speed of his car by manipulating the flow of gasoline." Bernays advised that to change the attitudes of the masses, a propagandist should target its "impulses, habits and emotions" and make "emotional currents" work to achieve the goal. Indeed, some contemporary authors have attributed the popularity of the most destructive political forces in modern history to the ability of their propagandists to enchant (rather than convince) publics and to oppose "the heavenly ecstasies of religious fervor" to "naked self interest" and individualism. Similarly,
Drew Westen, professor of psychology psychiatry and behavioral sciences at Emory University, using current psychiatric and psychological research to demonstrate the power of emotions in affecting political cognition and preferences, wrote that, "when reason and emotion collide, emotion invariably wins". Westen, an advisor to Democratic
political campaigns, believes that evolution has equipped people to process information by emotions and that people respond to emotional cues more than to rational arguments. Accordingly, Westen believes that emotion is vital for effective persuasion and that appeals to emotion will always be more effective than appeals to reason: ::A central aspect of the art of political persuasion is creating, solidifying, and activating networks that create primarily positive feelings toward your candidate or party and negative feelings toward the opponent … ::You can slog it for those few millimeters of cerebral turf that process facts, figures and policy statements. Or you can … target different emotional states with messages designed to maximize their appeal. ==Modern theories==