Crossing effects in the tactile temporal order judgment task: a meta-analysis

The tactile temporal order judgment (TOJ) task is widely used in multisensory neuroscience. Participants judge which of two tactile stimuli, one on each hand, came first. A key finding is that TOJ performance declines when the arms are crossed, likely due to interactions among tactile, proprioceptive, and visual information. The TOJ crossing effect has been widely reported. However, studies have used different analysis methods, leaving open the question of whether the choice of method influences the magnitude of the effect. Some studies have also reported that the crossing effect is modulated by moderators such as the availability of visual information, response modality, or speeded-response requirements. Through a systematic, exhaustive literature search, we identified 85 experiments in 51 publications that investigated the TOJ crossing effect, of which 39 experiments from 29 publications reported sufficient information for inclusion in a meta-analysis and aligned with the focus of our study. This analysis estimated the crossing effect's size at approximately 1.45. Checks for potential publication bias indicated that this estimate may be inflated, with a corrected estimate of 0.97 using a regression-based adjustment for small-study effects (Rücker's method) and 1.4 based on p-curve analysis of the reported p-values. Although analysis method and response mode were identified as significant moderators, most moderators and specific contrasts were not statistically significant, likely because too few studies were available to achieve adequate statistical power. The large effect size supports the TOJ task's use in other research areas, e.g., developmental and clinical. However, the lack of significant moderation suggests caution when applying the task to questions beyond the crossing effect itself.