Examiner-examinee interaction that takes place in the few minutes between individual tests. The interaction might include general reminders for the examinee to answer all questions truthfully (in the case of PLC techniques), or further emphasizing the comparison questions. Some research suggests that inter-chart stimulation may improve the validity of polygraphy, though it remains a controversial procedure. See: Abrams (1999); Honts (1999; 2000); Matte (2000).