Response Priming Accounts for Self-Prioritization Effects

Self-prioritization effects found in label-shape matching tasks have been demonstrated extensively. Participants are faster to match label-shape label-shape stimuli against a prelearned mapping, the more self-related the label is. The effect is thought to be driven by special cognitive treatment, saliency, or attentional prioritization of self-referential stimuli. However, the exact underlying mechanism remains elusive. We propose an alternative explanation, namely that self-related labels facilitate matching performance by inducing the so-called self-positivity bias (people tend to represent themselves more positively than they represent others), which is conducive to matching. To test this idea, we skipped the learning of label-shape mappings in our task. Furthermore, we used a shape-shape matching task. Thus, participants did not have to determine whether label-shape combinations match a previously learned mapping, but merely whether two geometrical figures are the same (match) or not (mismatch). Crucially, each trial was preceded by a more or less self-related prime word. This setup enabled us to measure self-prioritization effects in the absence of task directed links between target and self-related stimuli. In Experiment 1, self-related labels ("YOU", "FRIEND", "STRANGER") resulted in faster matching responses. Experiment 2 replicated the effect and ruled out word length as an alternative explanation (prime words: "YOURSELF", "FRIEND", and "OTHER"). Our findings suggest that the self-positivity bias at least contributes to self-prioritization effects. Furthermore, our theory explains interaction effects between match versus mismatch trials and self-relatedness of the labels, as found in many experiments.