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Poor calibration and inaccurate drift correction can pose severe problems for eye-tracking experiments requiring high levels of accuracy and precision. We describe an algorithm for the offline correction of eye-tracking data. The algorithm conducts a linear transformation of the coordinates of fixations that minimizes the distance between each fixation and its closest stimulus. A simple implementation in MATLAB is also presented. We explore the performance of the correction algorithm under several conditions using simulated and real data, and show that it is particularly likely to improve data quality when many fixations are included in the fitting process.

People are biased toward believing that what others say is what they truly think. This effect, known as the truth bias, has often been characterized as a judgmental error that impedes accuracy. We consider an alternative view: that it reflects the use of contextual information to make the best guess when the currently available information has low diagnosticity. Participants learnt the diagnostic value of four cues, which were present during truthful statements between 20% and 80% of the time. Afterwards, participants were given contextual information: either that most people would lie or that most would tell the truth. We found that people were biased in the direction of the context information when the individuating behavioral cues were nondiagnostic. As the individuating cues became more diagnostic, context had less to no effect. We conclude that more general context information is used to make an informed judgment when other individuating cues are absent. That is, the truth bias reflects a smart guess in a low diagnostic world.

We are skilled at reading other’s intentions – until they try to hide them. We are biased towards taking at face value what others say, but it is not clear why. One possibility is that we are uncertain, and make the decision by relying on heuristics. Half of our participants judged whether speakers were lying or telling the truth. The other half did not have to commit to a judgment: they were allowed to say they were unsure. We expected these participants would no longer need to rely on simplified heuristics and so show a reduced bias compared to the forced choice condition. Surprisingly, those who could say they were unsure were more biased towards believing people. We consider two possible accounts, both highlighting the importance of examining raters’ uncertainty, which have so far been undocumented. Allowing raters to abstain from judgment gives new insights into the judgment-forming process.

We measured the continuous bodily motion of participants as they lied to experimenters. These lies were spontaneous rather than elicited, and occurred for different motivations. In one situation, participants were given the opportunity to lie about their performance on a maths test in order to win money. In another, they witnessed one experimenter accidentally break a laptop. When asked what had happened, participants were motivated to lie and deny any knowledge. Across these situations, participants lied 61% of the time, allowing us to contrast the body movements of liars with truth tellers as they answered neutral and critical questions. Those who lied had significantly reduced bodily motion. In one case this motion appeared before the experimenter had even asked the critical question. We conclude that a person’s bodily dynamics can be indicative of their cognitive and effective states, even when they would rather conceal them.

The way that we look at images is influenced by social context. Previously we demonstrated this phenomenon of joint perception. If lone participants believed that an unseen other person was also looking at the images they saw, it shifted the balance of their gaze between negative and positive images. The direction of this shift depended upon whether participants thought that later they would be compared against the other person or would be collaborating with them. Here we examined whether the joint perception is caused by beliefs about shared experience (looking at the same images) or beliefs about joint action (being engaged in the same task with the images). We place our results in the context of the emerging field of joint action, and discuss their connection to notions of group emotion and situated cognition. Such findings reveal the persuasive and subtle effect of social context upon cognitive and perceptual processes.