"A is better than B, while B is better than C. Then is A better than C?" The process of making a decision in replying to this question -- transitive inference -- was studied. Experiments were conducted under conditional discrimination task using linear 5-item and 7-item stimuli, and loop 5-item and 7-item stimuli with university students as subjects. One group of subjects was given prior instructions about the serial stimuli they would be presented with, while another group was not taught that the stimuli will be in any order. Effects of the instructions were studied. Symbolic distance effects were observed in the university students. And the results of the group of students with prior knowledge of the serial stimuli were similar to those of animals and infants.