Can Damasio's Somatic Marker Hypothesis Explain More Than Its Originator Will Admit?

Abstract

It is a very old conjecture that emotion governs human choice. Early philosophers like Epicurus (1993) and Aristippus of Cyrene [see Parry (2014)] appear to have held this assumption, often described as “psychological hedonism” [see Overskeid (2002)]. British thinkers of the 18th and 19th century were among the most important exponents of psychological hedonism. In a well-known dictum, Bentham (1823, p. 1) left little doubt as regards his own view: “Nature has placed mankind under the governance of two sovereign masters, pain and pleasure. … They govern us in all we do, in all we say, in all we think …” Famously affirming that human rationality or reason could never on its own control behavior, Hume (1739) was equally clear. Indeed, he claimed (p. 413) that reason “can never oppose passion in the direction of the will.” Instead, said Hume (p. 415), “Reason is … the slave of the passions, and can never pretend to any other office than to serve and obey them.” In the second half of the 20th century, psychologists and neuroscientists tended [with some exceptions, such as Toda (1980)] to stay away from the question of how reason and emotion interact to govern human conduct. Important in turning the tide, however, helping researchers see the role of emotions in thinking and decision making, were Damasio and his co-workers (e.g., Damasio, 1994; Bechara et al., 1997). Damasio (1994) argued convincingly that there is no necessary conflict between reason and emotion—indeed, that emotion can support rational thought, and often does. To describe how cognition and emotion can interact when people choose, Damasio developed the somatic marker hypothesis (SMH). Central to the SMH is the assumption that people often do not choose on the basis of intellectual analysis alone, but also based on emotions elicited as part of the decision-making process. Verweij and Damasio (2019, p. 2) explain: “[T]he elements in this process—such as the options before us or the anticipation of the consequences of selecting one or another option—trigger emotive responses and generate the corresponding feelings or the corresponding covert signals, which can bias decisions nonconsciously.” Though demonstrating that choice can be controlled by emotions, Damasio (1994) held that this is not always the case. He described several circumstances under which the somatic marker mechanism cannot, in his view, explain why people choose the way they do. On p. 173, he states, “Somatic markers may not be sufficient for normal human decision-making since a subsequent process of reasoning and final selection will still take place in many though not all instances.” He adds (p. 196) that “logical competence does come into play beyond somatic markers.” Furthermore, says Damasio (1994, p. 177): “Some sublime human achievements come from rejecting what biology or culture propels individuals to do” —though “freedom from biological and cultural constraints can also be a hallmark of madness and can nourish the ideas and acts of the insane.” These aspects of Damasio's hypothesis are worth discussing, since the SMH, though controversial, has been so influential—and the man behind the hypothesis has not changed his mind. A recent paper (Verweij and Damasio, 2019) repeats the claim that affect does not necessarily dictate our behavior. “On the basis of reasoning,” say Verweij and Damasio (2019, p. 3) “individuals are capable of making choices that are not in line with their emotive responses.”