In concurrent speaking tasks, participants of a study are asked to complete an activity specific to the experiment while simultaneously repeating an irrelevant word. For example, one may be asked to read a paragraph while reciting the word "cola" over and over again. Speaking the repeated irrelevant word is thought to preoccupy the articulators used in subvocalization. Subvocalization, therefore, cannot be used in the mental processing of the activity being studied. Participants who had undergone the concurrent speaking task are often compared to other participants of the study who had completed the same activity without subvocalization interference. If performance on the activity is significantly less for those in the concurrent speaking task group than for those in the non-interference group, subvocalization is believed to play a role in the mental processing of that activity. The participants in the non-interference comparison group usually also complete a different, yet equally distracting task that does not involve the articulator muscles (i.e. tapping). This ensures that the difference in performance between the two groups is in fact due to subvocalization disturbances and not due to considerations such as task difficulty or a divide in attention.