The increasing presence of computers in society calls for the need to better understand how differently the sociocognitive mechanisms involved in natural human relationships operate in human–robot interactions. In the present study, we investigated one fundamental aspect often neglected in the literatures on psychology and educational sciences: how the source of information, either human or computer, influences its perceived reliability and modulates cognitive and motivational processes. In Experiment 1, participants performed a reasoning task that presented cues following participants’ errors, helping them to succeed in the task. Using two levels of task difficulty, we manipulated the source of the cues as either a human or a computer. In addition to task accuracy, Experiment 2 assessed the impact of the information source on socially and nonsocially related dimensions of achievement goals. In Experiment 1, participants who believed that they received cues from a human teacher performed better on difficult trials compared to those who believed that they received cues from a computer. In Experiment 2, we replicated these findings by additionally showing that the nature of the source only had an impact on the socially related dimension of achievement goals, which in turn mediated the source’s effect on reasoning performance. For the first time, the present study showed modulations of cognitive and motivational processes resulting from the manipulation of the type of information source aimed at providing assistance with a reasoning task. The findings highlight the importance of considering the social and motivational aspects involved in human–computer interactions.