Inclusion of the term emotion appears somewhat artificial and is not necessarily related to any particular theory of emotions. Furthermore, the assumption that (r, s) is identical across individuals seems to be very strong and not very realistic.2 Model 2.1 Motivation and frameworkAs we have seen, emotions play a role in the arguments behind different models and explanations of the experimental results. However, none of the models presented so far makes explicit such role in a clear manner. Indeed, the idea that the decision-making process is influenced by emotions is very intuitive. There is also experimental evidence of emotional reactions to unfair offers as measured by skin conductance [21], and of how unfair offers elicit activity in brain areas related to both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex) [22]. In these and many other studies, it is also clear that if the emotion is perceived as negative (anger, frustration, sadness, etc.); as a consequence, it is more likely for a given offer to be rejected [23] [24]. Thus, it seems reasonable to try to understand behavior in UG as aPLOS ONE | DOI:10.1371/journal.pone.0158733 July 6,4 /Emotions and Strategic Behaviour: The Case of the Ultimatum Gamecombination of both emotion and cognition, allowing one to explain the experimental results from that departure point. One of the main contributors to the idea of two different but interacting systems in decision-making processes is nobel laureate Daniel Kahneman [25] [26]. Kahneman posits that such mechanism is governed by the interaction of two different systems, which he calls System 1 and System 2. Processes of System 1 are regarded as fast, effortless, automatic, associative and emotionally charged. System 2, in contrast, is responsible for processes that are slow, controlled, analytical, cognitively demanding and affect free. He suggests four ways in which a judgement or choice may be made [25]: 1. no intuitive response comes to mind, and the judgement is produced by System 2. 2. an intuitive judgement or intention is evoked, and a. is endorsed by System 2; b. serves as an anchor for adjustments that respond to other features of the situation; c. is identified as incompatible with a subjectively valid rule, and blocked from overt expression. In the context of our attempt to explicitly account for the influence of emotions on behavior, a relevant point is that experimental results show that the GS-9620 web average is an easily accesible quantity to System 1 [26]. It is thus tempting to suggest that in an UG, System 1 would rapidly perceive the even split as a benchmark and then trigger an emotional reaction according to the subjective validity (or fairness) of it. System 2 analysis would then correspond to that of a pure income-maximizer player. Interestingly, as discussed above, the average payoff appears as a measure of fairness in Rabin’s approach [9]. Having found a reasonable starting point for our model, the next step towards defining it is to be able to manipulate the concept of emotion. To that end, we rely on the so called Circumplex Model [27], in which emotions can be categorized in two different RP54476 price continuous dimensions: valence and arousal. Valence indicates whether the pleasure related to an emotion is either positive or negative, while arousal indicates the personal activity induced by that emotion. This emotion model has been used, for instance, by Schweitzer et al. [28] to build an agent-based model of.Inclusion of the term emotion appears somewhat artificial and is not necessarily related to any particular theory of emotions. Furthermore, the assumption that (r, s) is identical across individuals seems to be very strong and not very realistic.2 Model 2.1 Motivation and frameworkAs we have seen, emotions play a role in the arguments behind different models and explanations of the experimental results. However, none of the models presented so far makes explicit such role in a clear manner. Indeed, the idea that the decision-making process is influenced by emotions is very intuitive. There is also experimental evidence of emotional reactions to unfair offers as measured by skin conductance [21], and of how unfair offers elicit activity in brain areas related to both emotion (anterior insula) and cognition (dorsolateral prefrontal cortex) [22]. In these and many other studies, it is also clear that if the emotion is perceived as negative (anger, frustration, sadness, etc.); as a consequence, it is more likely for a given offer to be rejected [23] [24]. Thus, it seems reasonable to try to understand behavior in UG as aPLOS ONE | DOI:10.1371/journal.pone.0158733 July 6,4 /Emotions and Strategic Behaviour: The Case of the Ultimatum Gamecombination of both emotion and cognition, allowing one to explain the experimental results from that departure point. One of the main contributors to the idea of two different but interacting systems in decision-making processes is nobel laureate Daniel Kahneman [25] [26]. Kahneman posits that such mechanism is governed by the interaction of two different systems, which he calls System 1 and System 2. Processes of System 1 are regarded as fast, effortless, automatic, associative and emotionally charged. System 2, in contrast, is responsible for processes that are slow, controlled, analytical, cognitively demanding and affect free. He suggests four ways in which a judgement or choice may be made [25]: 1. no intuitive response comes to mind, and the judgement is produced by System 2. 2. an intuitive judgement or intention is evoked, and a. is endorsed by System 2; b. serves as an anchor for adjustments that respond to other features of the situation; c. is identified as incompatible with a subjectively valid rule, and blocked from overt expression. In the context of our attempt to explicitly account for the influence of emotions on behavior, a relevant point is that experimental results show that the average is an easily accesible quantity to System 1 [26]. It is thus tempting to suggest that in an UG, System 1 would rapidly perceive the even split as a benchmark and then trigger an emotional reaction according to the subjective validity (or fairness) of it. System 2 analysis would then correspond to that of a pure income-maximizer player. Interestingly, as discussed above, the average payoff appears as a measure of fairness in Rabin’s approach [9]. Having found a reasonable starting point for our model, the next step towards defining it is to be able to manipulate the concept of emotion. To that end, we rely on the so called Circumplex Model [27], in which emotions can be categorized in two different continuous dimensions: valence and arousal. Valence indicates whether the pleasure related to an emotion is either positive or negative, while arousal indicates the personal activity induced by that emotion. This emotion model has been used, for instance, by Schweitzer et al. [28] to build an agent-based model of.
