Performance Validity Tests (PVTs) are widely used for the detection of sub-optimal effort and malingering in neuropsychological assessments. Threats to their validity however likely to intensify with time (e.g., information available on the web or from legal representatives) and may lead to a decline in their ability to differentiate between malingerers and non-malingerers. Eye movements and response time (RT) are less obvious outcome measures and under less conscious control than more conventional PVT indices (e.g., accuracy). They are therefore promising measures that can aid in detecting malingering when used in conjunction with more conventional PVT indices. The Word Memory Test (WMT) is a widely used PVT in neuropsychological evaluations. As part of the proposed study, TBI patients, chronic pain patients and healthy adults (60 in each group) will be randomly divided to one of two conditions; optimal effort or sub-optimal effort (participants will be asked to play a TBI patient who wishes to present himself as having cognitive deficits or exaggerate existing cognitive deficits). The proposed study will improve the WMT's efficacy in detection of sub-optimal effort in neuropsychological evaluations and therefore protect its validity from future threats. In addition, the proposed study will provide us with better understanding of the effect of TBI on eye movements and RTs in general.