Piotr Winkielman and Kent C. Berridge
action that are attributable to one’s emotional state, independent of his or her conscious awareness of that state. (p. 432)
Unconscious Elicitation of Conscious Affective Reactions Research advances in the past few years challenge the traditional view by demonstrating ‘‘unconscious emotion,’’ at least in a limited sense of unconscious causation. Several studies have shown that stimuli pre- sented below awareness can elicit an affective reaction that is itself consciously felt. An example is subliminal induction of the mere- exposure effect, that is, a positive response to repeatedly presented items. In one study, some participants were first subliminally exposed to several repeated neutral stimuli consisting of random visual pat- terns. Later, those participants reported being in a better mood—a conscious feeling state—than participants who had been subliminally exposed to neutral stimuli that had not been repeatedly presented (Monahan, Murphy, & Zajonc, 2000). In other studies, changes in self- reported mood have been elicited by subliminal presentation of pos- itive or negative images, such as pictures of snakes and spiders
¨ presented to phobic individuals (Ohman, Flykt, & Lundqvist, 2000).
But asserting that subliminal stimuli may cause emotion is different from asserting that emotional reactions themselves can ever be un- conscious (Berridge & Winkielman, 2003; Kihlstrom, 1999). The re- search we just mentioned still fits into the conventional view that once emotions are caused, they are always conscious. In fact, these studies relied on introspective reports of conscious feelings to demonstrate the presence of emotion once it was unconsciously caused.
So the question remains: Can one be unconscious not only of the causes of emotion, but also of one’s own emotional reaction itself— even if that emotional reaction is intense enough to alter one’s be- havior? Studies from our lab suggest that the answer is yes. Under some conditions, people can have subliminally triggered emotional reactions that drive judgment and behavior, even in the absence of any conscious feelings accompanying these reactions.
Unconscious Emotional Reactions Strong Enough to Change Behavior We agreed that stronger evidence was needed. Proof of unconscious emotion requires showing that participants are unable to report a conscious feeling at the same time their behavior reveals the presence of an emotional reaction. Ideally, the emotional reaction should be strong enough to change behavior with some consequences for the individual. To obtain such evidence, we assessed participants’ pouring and drinking of a novel beverage after they were subliminally exposed to several emotional facial expressions (Berridge & Winkielman, 2003; Winkielman et al., in press). The general procedure of these ex- periments can be seen in Figure 1. Participants were first asked if they were thirsty. Next, they were subliminally exposed to several emo- tional expressions (happy, neutral, or angry) embedded in a cognitive task requiring participants to classify a clearly visible neutral face as male or female. Immediately afterward, some participants rated their feelings on scales assessing emotional experience and then were given a novel lemon-lime beverage to consume and evaluate. Other partici- pants consumed and evaluated the beverage before rating their feel- ings. Specifically, in Study 1, participants were asked to pour themselves a cup of the beverage from a pitcher and then drink from the cup, whereas in Study 2, participants were asked to take a small sip of the beverage from a prepared cup and then rate it on various dimensions, including monetary value.
In both studies, conscious feelings were not influenced by sub- liminal presentation of emotional faces, regardless of whether partic- ipants rated their feelings on a simple scale from positive to negative mood or from high to low arousal, or on a multi-item scale asking about specific emotions, such as contentment or irritation. That is, participants did not feel more positive after subliminally presented happy expressions than after subliminally presented neutral expres- sions. Nor did they feel more negative after angry expressions than after neutral expressions. Yet participants’ consumption and ratings of the drink were influenced by those subliminal stimuli—especially
Uncorrected and Unremembered Emotional Reactions In an initial attempt to demonstrate unconscious emotion, a series of studies examined participants’ ratings of neutral stimuli, such as Chinese ideographs, preceded by subliminally presented happy or angry faces (Winkielman, Zajonc, & Schwarz, 1997). Some partici- pants in those studies were asked to monitor changes in their con- scious feelings, and told not to use their feelings as a source of their preference ratings. Specifically, experimental instructions informed those participants that their feelings might be ‘‘contaminated’’ by ir- relevant factors, such as hidden pictures (Study 1) or music playing in the background (Study 2). Typically, such instructions eliminate the influence of conscious feelings on evaluative judgments (Clore, 1994). However, even for participants told to disregard their feelings, the subliminally presented happy faces increased and subliminally presented angry faces decreased preference ratings of the neutral stimuli. This failure to correct for invalid feelings indicates that participants might not have experienced any conscious reactions in the first place. Indeed, after the experiment, participants did not remember experiencing any mood changes when asked about what they had felt during the rating task. Still, memory is not infallible. A skeptic could argue that participants had conscious feelings immediately after subliminal exposure to emotional faces, but simply failed to remember the feelings later. Thus, it is open to debate whether these studies demonstrate unconscious emotion.
Fig. 1. Sequence of events in research investigating the impact of sub- liminally presented emotional facial expressions. First, participants are subliminally exposed to several expressions of the same valence (happy, neutral, or angry). The expressions are hidden by a visible neutral face that participants classify as male or female. Second, participants pour and drink a beverage and report their conscious feelings (in counter- balanced order).
Volume 13—Number 3