4.5 Conclusion
The STP approach is a reliable and valid method to measure peak amplitude and latencies in single trials in the speeded flanker task. The averaged ERP approach is useful in certain situations such as when the components of interest are stable across individuals, and when there is little interest in individual differences or change over time. However, if there is variability across individuals or when trying to examine changes over time, the STP approach would provide valuable information about brain activity. Contrary to the assumptions often made to justify averaging across trials, the present study shows that the peaks in the single trial are large enough to be measured, that the brain’s response to a stimulus is not invariant, and systematically changes occur over successive trials. While the STP approach is not the only way to measure single trial data, it is a parsimonious way of measuring ERP components at the trial level that can be easily replicated and interpreted by ERP researchers across labs.