Music can reduce cognitive dissonance

34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 The fundamental cognitive functions of music in the brain have not been known and evolutionary reasons for musical abilities seem mysterious. A recent hypothesis suggested that a fundamental function of music has been to help mitigating cognitive dissonances. A cognitive dissonance is “a discomfort caused by holding conflicting cognitions” simultaneously; it usually leads to devaluation of conflicting knowledge. Since every concept implies some degree of contradictions to other knowledge, unmitigated cognitive dissonances could prevent evolution of cognition. Thus music might be fundamental for the evolution of cognition. Here we provide experimental confirmation of this hypothesis using a classical paradigm known to induce a cognitive dissonance and devaluation of a dissonant object; in presence of music devaluation has not occurred. N at ur e P re ce di ng s : h dl :1 01 01 /n pr e. 20 12 .7 08 0. 1 : P os te d 1 A pr 2 01 2 Debates on the origin and function of music have a long history. Aristotle listed the power of music among the unsolved problems. Kant 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 , who so brilliantly explained the epistemology of the beautiful and the sublime, could not explain music. According to Darwin, the human musical faculty “must be ranked amongst the most mysterious with which (man) is endowed” because music is a human cultural universal that appears to serve no obvious adaptive purpose. While some scientists argue that music itself plays no adaptive role in human evolution, others suggest that music clearly has an evolutionary role, and point to music’s universality. In 2008, Nature published a series of essays on music. The authors agreed that music is a cross-cultural universal, still “none... has yet been able to answer the fundamental question: why does music have such power over us?” “We might start by accepting that it is fruitless to try to define ‘music” . Recently, we have presented a hypothesis about the fundamental cognitive function of music. It suggested that the evolution of language led to relatively fast cultural evolution of multiple mutually contradictory concepts (any different concept must be contradictory to some extent; otherwise one concept would be sufficient). This created cognitive dissonance and consequently led to devaluing knowledge. If cognitive dissonance could not be mitigated, our progenitors would devalue knowledge, and human language, knowledge, and culture would not evolve. It was hypothesized that the fundamental function of music in cognition was to serve precisely this function. The purpose of the study reported here was to experimentally explore this possibility. A cognitive dissonance is a discomfort caused by holding conflicting cognitions. Ancient Greeks new that people tend to resolve the dissonances by devaluing a conflicting cognition. In the Aesop’s fable The Fox and the Grapes a fox sees high-hanging grapes. A desire to eat grapes and inability to reach them are in conflict. The fox overcomes this cognitive dissonance by deciding that the grapes are sour and not worth eating. Since the 1950s cognitive dissonances became a wide and well studied area of psychology. It is known that tolerating cognitive dissonances is difficult, and people often make irrational decisions to avoid them. In 2002 this research was awarded Nobel Prize in economics, emphasizing the importance of this field of research. Our findings that music can reduce cognitive dissonances are tentatively supported by known brain mechanisms. Previous research demonstrated involvement of the anterior cingulate gyrus in creating cognitive dissonances. At the same time, it is known that listening music decreases activity of the ventral medial prefrontal cortex as well as the N at ur e P re ce di ng s : h dl :1 01 01 /n pr e. 20 12 .7 08 0. 1 : P os te d 1 A pr 2 01 2 limbic system, making listening more pleasurable, so that activation of the anterior cingulate gyrus is decreased 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 . In the present study, cognitive dissonance was experimentally created in 4-year-old children using a well-established method (the induced-compliance paradigm). The general procedure adopted in the present experiment was essentially identical with that of the previous research. With each child an experimenter first played an “evaluation game” to elicit a toy ranking. In the next session, while a child was playing with toys, an experimenter said “I have to leave now for a few minutes to do an errand. But why don’t you stay here and play with these toys while I am gone? I will be right back. You can play with this one [pointing], this one, and this one. But I don’t want you to play with [mentioning the name of the second-ranked toy].” According to the previous research this was expected to create a cognitive dissonance, and eventually result in devaluing the second-ranked toy. Exactly this result was observed, when the experimenter returned and played “ranking game” again: the toy previously ranked as the second was devalued to near bottom rank. An experiment with another group of children was only different in one respect. The participants were exposed to music (one of Mozart’s sonatas) while playing alone. If music indeed helped mitigating cognitive dissonance as previously hypothesized in, we would expect that devaluing of the second-ranked toy would be not as strong as without music, or possibly no devaluation would occur at all. This is exactly what was observed. The group of children exposed to music did not devalue the “forbidden” toy. We concluded that indeed music helped mitigating the cognitive dissonance and no devaluation was needed. Other aspects of the experiment were designed to confirm that our results are consistent with those previously reported by other researchers and are typical for cognitive dissonance and the following devaluation (without music). They are reported in the following sections. They are not essential for the main reported result that music helps mitigating cognitive dissonances. The results of changes of the participant’s ranking of the attractiveness of a “forbidden” toy are summarized in Table 1. With exposure to music, 15 of the 25 participants increased their rating of the toy, 7 did not alter their rating, and 3 decreased it. Whereas without exposure to music 5 participants increased their rating, 14 did not N at ur e P re ce di ng s : h dl :1 01 01 /n pr e. 20 12 .7 08 0. 1 : P os te d 1 A pr 2 01 2 alter and 6 decreased it. The difference between the two conditions was statistically