When does the stroop effect not work?

The Stroop effect may not work effectively when participants have strong practice or familiarity with the task, such as extensive training in color-Word associations. Additionally, when the task is modified to include incongruent stimuli that are less salient or when participants are distracted, the effect can diminish. Furthermore, individuals with certain cognitive impairments or those who are highly focused on a specific task may also show reduced Stroop interference.