Sender credibility and deception detection.

•We investigated the relationships between credibility and deception detection success.•Participants communicated either through voice-over-IP (VOIP) or by e-mail.•Deception detection was worse when deceivers were seen as credible.•Untrained and unmotivated deception detectors found deceivers to be credible.•VOIP users were more likely to find deceivers credible than were e-mail users.