Somatic Markers and Frequency Effects: Does Emotion Really Play a Role on Decision Making in the Iowa Gambling Task?

Somatic Markers and Frequency Effects: Does Emotion Really Play a Role on Decision Making in the Iowa Gambling Task? Danilo Fum (fum@units.it) Antonio Napoli (napoli@psico.units.it) Dipartimento di Psicologia, Universita degli Studi di Trieste via S. Anastasio, 12 34124 Trieste (Italy) Andrea Stocco (stocco@cmu.edu) Department of Psychology, Carnegie Mellon University 5000 Forbes Ave., Pittsburgh, PA 15213 Abstract The role of the frequency of wins and losses in the Iowa Gambling Task (Bechara, A., Damasio, A., Damasio, H., & Anderson, S. 1994. Insensitivity to future consequences following damage to human prefrontal cortex. Cognition, 50, 7–15) was investigated in 2 experiments manipulating the long-term expected value of the decks participants had to choose from. The first experiment adopted the typical setting of the task in which every card selection was followed by a monetary win, while losses happened only occasionally. In the second experiment every decision led to a loss while the contingent event was represented by wins. In both experiments the long-term expected value of the decks did not seem to influence the participants’ choices that were, however, sensitive to the frequency with which the decks produced the contingent event. Immediate gains or losses associated with the decks exerted their effect on the first few choices only. The relevance of these findings for Damasio's Somatic Markers Hypothesis are discussed. Keywords: Decision making; Emotion; Somatic markers hypothesis, Iowa gambling task; Frequency effects. The Somatic Markers Hypothesis The last years have witnessed a deep revaluation of the role of emotions in decision making, and the idea that feelings and sentiments could affect the way people make their decisions has gained increasing acceptance (Connolly, & Zeelenberg, 2002; Lee, 2006; Loewenstein, 2000; Rottenstreich & Hsee, 2001; Schwarz, 2000; Slovic, Finucane, Peters, & MacGregor, 2004; Wang, 2006). An influential part in this revaluation has been played by the Somatic Markers Hypothesis (SMH) put forward by Antonio Damasio and coworkers (Damasio, 1994; Damasio, 1996; Bechara & Damasio, 2005). The SMH originates from the attempt to understand the difficulties experienced by patients with neurological damage in the ventromedial prefrontal cortex (VMPFC) who present both emotional problems and difficulties in making decisions in their personal and social sphere. These patients are unable to express their feelings and to experience those affects that are normally evoked by emotionally arousing situations. On the other hand, while their basic cognitive capabilities (attention, memory, reasoning, etc.) are preserved, they run into troubles in making decisions concerning work, family and friends, money, or moral issues. People with VMPFC damages are unable to foresee the long term consequences of their actions, and are incapable of learning from their mistakes. Their choices are characterized by a “myopia for the future” (Bechara et al., 1994), and are very different from those that were made before the neurological damage. According to the SMH, there exists a relationship between these problems: the difficulties experienced by VMPFC patients in their decision making could depend on the faulty workings of an emotional mechanism that in healthy persons is capable of rapidly signalling the (positive or negative) consequences of an action, freeing people from pondering about any possible option, and helping them to make advantageous and profitable decisions. This regulatory mechanism is constituted by the so-called “somatic markers”. The SMH assumes that decision making is influenced by neurobiological biasing signals (markers) generated by the system underlying emotions. When experiencing an emotionally arousing event, a set of changes is produced that concern both the body and the brain. The bodily (or somatic) modifications deal with the internal milieu (viscera, heart, glands, smooth muscles, etc.), the external posture and behaviour, while brain effects lead to neurotransmitters release, the updating of somatosensory maps and the transmission of signals to somatosensory regions. Once a somatic state has been induced by an emotionally arousing experience, a pattern is made for it. Any stimulus capable of triggering memories or thoughts related to the experience reenacts this pattern generating a somatic state similar to that generated by the original event. While making a decision, for any possible choice a somatic marker is produced that indicates the positive or negative value of what is being taken into account. In dealing with complex and uncertain situations, the somatic markers help to reduce the options space to treatable dimensions by marking them with an emotional signal. Only the options marked as promising are considered for further deliberation, while the less attractive ones are ignored. Rational decision making could thus be considered as a combination of deliberate top- down reasoning, in which an in-depth analysis of the effects of a conceivable action is performed, and a quick bottom-up screening, based on somatic markers, that indicates how likely a given action is to lead to positive or negative effects.