In computer-assisted instruction, primary causes for the main problems are student's feeling lonely and lack of social learning environment. Pedagogical agents, which could enable students to use software, have been developed and integrated into instructional software to remove the obstacles mentioned. The main purpose of the study is to compare the effects of a fixed pedagogical agent and multi pedagogical agents left to students' choice on dependent variables. Additionally, it has also been examined if computer assisted instruction software without pedagogical agent has any effects on dependent variables. The study seeks to investigate both learners' agent preferences and the effects of pedagogical agents on learners' academic success, motivation and cognitive load. For the purpose of the study, four groups were formed. The first group used educational software via fixed agent, the second group used educational software with the option to choose among several agents whereas the third group used educational software without agent and the fourth group received the same education through traditional way. The academic success refers to MS Excel program literacy. The findings revealed no statistically significant difference between fixed and multi pedagogical agents in terms of dependent variables. However, the designs with agents were found to have positive effects on learners' motivation, academic success and cognitive load. The results also indicated that pedagogical agents should be used in all computer-assisted instruction software. Another finding of the study is that the students in younger age groups tend to prefer the same gender agent as theirs. Furthermore, feedback from participants showed that users of multi pedagogical agents would like to conceive their own pedagogical agents. Accordingly, it is suggested that learners should be provided with programs that can be personalized depending on learners' needs and preferences. (C) 2017 Elsevier Ltd. All rights reserved.