The observed RTs are consistent with those from the study by Crump et al. (2013), who reported a compatibility effect of 34 ms in the 96-ms condition, whereas we found a compatibility effect of 16 ms in that condition.
They reported a negative compatibility effect of about 12 ms in the 16-ms condition, very similar to the 10 ms from our results.
Notably, Beecham et al. [27] reported spatial stimulus-response compatibility effects for both number and pitch together, but with independence of these effects.
We computed the compatibility effect for each individual participant by subtracting the mean score of all compatible trials from that of all incompatible trials.
In line with our argument for the stronger compatibility effect, symptoms of object-based neglect should result in particular difficulties for both the processing of carry and borrow problems in neglect patients because in both cases specific reference to the neglected tens digit is necessary.
The absence of spatial compatibility effects at strong temporal overlap suggests that response conflicts due to stimulus-related priming depend on the availability of processing resources.
The observation that size of compatibility effect and accuracy of number-line mapping both correlated with mental rotation performance, but not with each other, fits neatly with our initial predictions: namely, that these two measures may each primarily recruit separate aspects of spatial representation (precision versus quantity) which are both utilized in mental rotation.
This would seem to indicate that larger compatibility effects would accompany a more complex, advanced system of number representation; indeed, developmental studies of the compatibility effect have shown it to increase with age and numerical experience (Mann, Moeller, Pixner, Kaufmann, & Nuerk, 2011) and to predict later arithmetic ability (Moeller et al., 2011).
Both imitative and spatial compatibility effects were apparent on response times; however, the effect of imitative compatibility was significantly stronger, indicating less control of imitation, during stimulation of the rTPJ relative to the control site.
There was no significant main effect of participant group or a significant difference between the compatibility effects between participant groups on zRT as indicated by the Jonkheere-Terpstra test for monotone trend in group medians (both p > .15) nor a main effect of compatibility (p > .30, evaluated by the Wilcoxon-signed-ranks test in any of the respective participant groups).
