A study was carried out to test a hypothesis about the different impact that sign and its meaning  can have upon concept formation. False memories approach was used to create expectations of a certain meaning in the subjects, who subsequently had to form an artificial concept in the absence of a sign. The concept formation under sign-absence condition was compared to that under the absence of both sign and meaning condition, and under the presence of both a redundant sign and a meaning condition. The results indicated differences in the concept formation under the latter (presence of both sign and meaning) condition, compared to the former two conditions. The results suggest that sign plays a more important role, compared to its meaning, in the process of concept formation.