The smell of altruism: Incidental pleasant odors and chemosignal as prosocial decisions moderators

The study of the interactions between olfaction and the decision making processes has mainly focused on the investigation of what is considered the most useful odor to disperse in the air to drive the consumers' choices to prefer a product rather than another one. Despite the fact that some studies showed the existence of associations between odors and prosocial behavior, much less data are available on the links between olfaction and donation in favor of public goods. Thus, the main purpose of the series of experiments described in this thesis is precisely that to shed some light on the investigation of the nature of pleasant odor-decision and on the chemosignal-decision associations. In order to achieve this, the presence of an odor and the congruence between odor and decision task has been manipulated, and the decision to donate has been tested in different domains. Therefore, in the first series of experiments, we manipulated the presence of an ambient pleasant odor, expecting that the congruent stimuli sharing the more stable association odor-concept, would have resulted in an overall increase in the WTC (willingness to contribute) and WTP (willingness to pay) in the decision to donate in favor of a public good. The results confirmed the existence of an association between the olfactory stimulus congruence and the amount donated in favor of a public good. Interestingly, this effect is confirmed in both hypothetical and real decision settings. Moreover, the stimulus modality was manipulated presenting congruent olfactory or visual stimuli. Our findings confirmed the preferential link between olfaction and cognitive processes and showed higher donations in the olfactory setting (compared to the visual one). The existence of associations between odors and words are examined to know if the odors could semantically drive cognitive processes different from decision making. The results confirmed the existence of an association between the olfactory stimulus pleasantness and the performance in a lexical decision task (LDT). Thus, this effect is mediated by the presence of a pleasant odor and not by the semantic congruence between odor and the presented words. Moreover, the visual modality tend to worsen the LDT performance even if the visual stimulus was semantically congruent with the word presented. Finally, even though the semantic link appears to be crucial for cognitive processes such as decision, it seems not so important for memory and linguistic processes involved in the LDT. The second series of studies involved the presence of chemosignal, expecting that the congruity between stimulus and decision (the chemosignal used is AND, known as the best candidate to be considered a human chemosignal) would have resulted in an overall increase in amount of money donate to unknown persons during Dictator and Trust Game. The results confirmed the existence of an association between the chemosignal stimulus presence (and its olfactory experience) and the amount donated, and a mediation effect due to the positive mood (in presence of AND) especially in females and with high AND concentration.