People who score high on the personality trait Machiavellianism do not shy away from exploiting others for their own benefit. Here, we investigated the effect of Machiavellianism on attacker...Show morePeople who score high on the personality trait Machiavellianism do not shy away from exploiting others for their own benefit. Here, we investigated the effect of Machiavellianism on attacker exploitation. We hypothesized that attackers high on Machiavellianism will exploit their economic opponent and thus invest more into conflict. To test our hypothesis, we used the economic Attacker-Defender Contest (AD-C), an experimental game created for studying conflict. In the game, if the attacker invests more into conflict than the defender, they take what the defender had left after they invested, hereby exploiting the defender. In an online experiment, 301 participants completed the AD-C as either an attacker or a defender. We assessed Machiavellianism by means of the Short Dark Triad (SD3) measure. A simple linear regression led to the conclusion that Machiavellianism is unrelated to attacker conflict investment. Interestingly, we did find an effect of Machiavellianism on attackers’ expectation of the defenders’ conflict investment. Attackers’ expectation, in turn, strongly affected conflict investment. The effect of Machiavellianism on expected investment connects to previous research, showing that Machiavellianism evokes expectations of selfish feelings in others. However, the concrete reason as to why Machiavellianism relates to expectation, but not conflict investment, remains unclear. Recommendations for future research include conducting research in an economic organization.Show less