The objective of this research is to investigate the personality factors that influence human decision-making in particular scenarios such as during the interaction with a robot or a human counterpart. We conducted the experiment in a public environment in which participants were approached by either a human or a robot agent. The agent asked a verbal request in a direct or indirect manner that participants could accept or decline. We used the Ten Item Personality Measure (TIPI) in order to measure the personality traits of the agent that had a strong influence in the acceptance decision of the participants. Our results suggest that within the context that our experiment took place, the humanoid robot was more effective at influencing human-decision making than the human agent, in particular when indirect request was used. The personality traits that made the robot to be more effective were: 'extrovert', 'enthusiastic' and 'sympathetic'.