Cross-modal anchoring: magnitude priming based on length leads to contrast effect in numerosity judgment

On one hand, Judgment and Decision Making (JDM) research reports a phenomena called the cross-modal effect, which shows that magnitude priming based on spatial attributes of a stimuli might influence numerical estimations. On the other hand, research directed at human cognition reports that processing of space and numbers may interfere. Despite different theoretical backgrounds, those two lines of research report similar results. Is it possible that the cross-modal anchoring and the interaction between space and number are just two manifestations of the same psychological effect, conceptualized within different paradigms? In Experiment 1 participants were asked to draw lines of different length and estimate numerosity of sets of dots presented for 100 ms. Based on current studies, magnitude priming is assimilated with subsequent numerical judgment. However, an unexpected contrast effect was observed in Experiment 1. Priming of “smallness” resulted in higher estimations of numerosity, while priming of “largeness” was associated with lower estimations. Short exposition time often leads to automatic attention processes, which could possibly account for the observed contrast effect. In Experiment 2 this assumption was tested, verifying potential differences between different exposition times (100 ms vs 300 ms). The same pattern of results was obtained. Findings of both experiments are discussed from the perspective of different anchoring paradigms and concepts related to space and number processing.