The primary aim of this research was to assess the adequacy of postexperimental inquiries (PEI) used in deception research, as well as to examine whether mood state, reward, or administering the PEI as a face-to-face interview or computer survey impacts participants' willingness to divulge suspicion or knowledge about a study. We also sought to determine why participants are not always forthcoming on the PEI. Study 1 examined how frequently PEIs are included in research and found that most researchers employing deception do use a PEI. Studies 2 and 3 showed that participants are often unwilling to divulge suspicion or awareness of deception or to admit to having prior knowledge about a study, though offering a reward and completing the PEI on a computer modestly improved awareness and admission rates. Study 4 indicated several reasons why participants may not reveal suspicion or knowledge about a study on the PEI.