The effect of emotion on conditional reasoning

In two experiments, we explore whether logical reasoning abilities are affected by emotion. In both experiments, we compared participants’ performance on a conditional reasoning task when the content was emotional and neutral. In Experiment 1, conditional statements included either emotional words or neutral words. In Experiment 2, we manipulated the emotional connotation of initially neutral words using a conditioning procedure. Words were repeatedly paired with either positive, negative, or neutral images. These words were then used in a conditional reasoning task. In both experiments, participants’ performance was more likely to deviate from prescriptions of normative logic when the content was emotional compared to when it was neutral. The idea that emotions affect people’s reasoning is widespread. There is a commonsensical notion that emotions have the power to disrupt logical thinking. This contrasts with current views in the scientific study of emotion that emphasize the functional aspects of emotions. There is however, a paucity of empirical work on the effect of emotion on reasoning. In two experiments reported here, we investigated whether conditional reasoning is affected by emotion. Contemporary approaches to the study of affect in psychology and the neurosciences have consistently emphasized the adaptive value of emotion. In fact, a functionalist account of emotions is often regarded as the cornerstone of current investigations of affective phenomena (Cornelius, 1996; Ekman & Davidson, 1994; Keltner & Gross, 1999). The functionalist approach is based on the notion that emotions serve important functions and that they provide benefits to individuals and groups who experience them. Interactions between cognition and emotion have been studied within this framework. Different types of empirical evidence support this general assumption. One type of evidence concerns the relation between reasoning abilities and the experience of affective states. Neurological research focusing on patients with specific brain lesions has shown that people who are unable to experience emotions are also seriously impaired on decision-making tasks, particularly when thinking about complex interpersonal situations (Damasio, 1994; Damasio, Grabowski, Frank, Galaburda, & Damasio, 1996; Dimitrov, Phipps, Zahn, & Grafman, 1999). This suggests that impairments in emotion actually produce deficits in normatively correct thinking. Thus, emotions may promote sound thinking rather than hinder it. This functionalist perspective is a radical departure from earlier philosophical views. Studies on non-clinical samples also support the view that emotions are adaptive. A number of cognitive biases associated with different emotional states have been identified by recent research (e.g., Forgas, 2000). For instance, anxiety, related to the basic fear system, produces systematic biases in attention towards threatrelated materials (Fox, Russo, Bowles, & Dutton, 2001; Mathews, Mackintosh, & Fulchner, 1997; Mogg, Bradley & Hallowell, 1994; Richards & French, 1992; Yiend & Mathews, 2001). Anxiety appears to modulate the cognitive system by channelling resources towards threat-related, highly relevant, materials. Thus, in most circumstances, and in moderation, cognitive biases associated with emotions are generally thought to be functional. While beneficial effects of emotion on cognition have recently been emphasized, potential impairments related to emotion remain relatively unexplored. Research in psychopathology does document that certain clinical disorders involving important emotional dysfunctions may be associated with impairments in reasoning (e.g., Pelissier & O’Connor, 2002). However, it is not clear whether these impairments are directly caused by the emotional dysfunctions or whether both the emotional and reasoning dysfunctions are manifestations of a general underlying aetiology. There are two specific issues concerning the effect of emotion on reasoning, and more specifically on logical reasoning performance. One possibility is that the affective state a person is experiencing affects their reasoning. Another is the possibility that the emotionality of the materials affects reasoning performance. In other words, do people reason differently when they reason about emotional and nonemotional materials? While there is some research on