A pre-registered experiment was conducted to examine psychophysiological responses to being lied to. See http://journal.frontiersin.org/Journal/10.3389/fpsyg.2014.00442/abstract for the registration (Registered Report). Bridging research on social cognition and deception detection, we hypothesized that observing a liar compared to a truth-teller would decrease finger skin temperature of observers. Participants first watched two targets while being unaware that they would later be asked to judge (direct and indirect) veracity, and then watched another two targets while aware of this. During both these awareness phases finger skin temperature was measured. When participants were observing a liar, irrespective of awareness, on average finger skin temperature declined over time. In the aware phase, temperature trajectories for truth-tellers stayed above those for liars, however, in the unaware phase, this pattern was reversed. Findings pertaining to temperature partly confirmed our main hypothesis yet require further research. Results did confirm our further hypotheses that participants judge liars as less likeable and less trustworthy than truth-tellers–an indication of indirect deception detection. Moreover, and also confirming our hypothesis, participants performed only around chance level when directly judging whether the target person was lying. Exploratory analyses are reported with regard to truth bias and dependency between direct and indirect veracity judgments. Limitations and directions for future work related to the existence of psychophysiological indicators of deception detection are discussed.