How do Faces Influence Behavior? A Proposal for Distinguishing between Mechanisms that Involve Cognitive inferences, Emotional Feelings, and Unconscious Affective Reactions.

Emotional stimuli - such as facial expressions, images, or text - can influence behavior, including important decisions. This influence is complex as these stimuli may engage multiple psychological and physiological processes. The processes encompass (i) perception, attention, and memory, (ii) motor patterns, (iii) central and peripheral circuitry, (iv) subjective feelings, and (v) inferences regarding the stimulus' meaning. All these processes can shape subsequent behavior. For example, a smile may communicate permission and encouragement to explore. A smile may also lift one's conscious mood, which, in turn, may serve as a basis for more favorable judgments. However, other mechanisms can operate without involving conscious feelings. In fact, in some studies on facial expressions, researchers observe shifts in attention, perception, and memory, changes in physiology (e.g., amygdala activation, sweating, respiration, heart rate) and behavior (e.g., approach, consumption, risky decisions), without participants reporting any feelings. In other studies, observed changes in behavior are causally unrelated to changes in feelings. In this article, we propose a framework distinguishing informational, feeling-based, and unconscious affective pathways of affective influence. We illustrate our framework with key studies, focusing on the variety of influences by facial expressions.