In this paper we study the influence of personality traits in ne-gotiation by using a methodology for automated cognitive be-havior analysis (ACBA). This methodology uses genetic pro-gramming (GP) for hypothesis generation and testing of hu-man behavior with the goal of explaining the underlying men-tal structures guiding people’s actions during a task. ACBA it-eratively generates programs—the hypotheses—capable of ex-plaining the behavior exhibited by an individual during a multi-level, multi-issue, sequential bargaining task against an artifi-cial agent. Our study focuses on the influence of the personal-ity traits of social-value orientation (SVO) and Machiavellian-ism (Mach). The results show that by using ACBA, we are ableto identify differences in the outcomes of programs emergingfrom GP that are consistent with the influences that differentSVO and Mach profiles have in human negotiation behavior.