The present study aimed to examine the relationship between emotional state and prosocial behavior. An experiment investigated the influence of picture valence and arousal on donation size. Based on self-reported emotions and physiological reactions’ data of 54 participants, we showed that valence and arousal are related to donation size. According to the received data, the participants donated more when they experienced negative and strong emotions. The results also showed that the ill health of pets is a crucial characteristic for collecting donations in a context of homeless dogs
