Background:
How suspicious individuals are about some information affects how they judge whether the information is truthful. Being suspicious increases the possibility of one making a lie judgment about others (judging that others are lying); however, previous research has rarely distinguished between two types of suspicion: dispositional and state. This study examined how dispositional suspicion affects deceptiveness impressions and veracity judgments under different levels of state suspicion. Also, the relationship between the two types of suspicion and the amount of information people gather for truth-lie judgments was explored.

Participants and procedure:
Participants (N = 260) watched videos of someone telling either the truth or a lie, and immediately rated how deceptive the speaker looked, then made a final veracity judgment about him/her. Participants were assigned to two conditions: in one, they were informed that the speaker in the video might have committed a crime (suspicious condition), while in the other, they were not (non-suspicious condition). Participants were allowed to watch a maximum of five videos before making the final decision, and they all reported their level of dispositional suspicion.

Results:
The results indicated that participants with high dispositional suspicion perceived the speaker as more deceptive than those with less suspicion but did not necessarily make more lie judgments. Although not statistically significant, there was a clear trend that the effect of dispositional suspicion was evident only under low-state suspicion. It was also found that more suspicious participants gathered less information.

Conclusions:
The finding that dispositional suspicion and state suspicion interactively influence deception perception has practical implications for judgments under low suspicion (e.g., fraud).