Testing the memory encoding cost theory using the multiple cues paradigm

Recent developments have introduced the Memory Encoding Cost (MEC) theory to explain the role of attention in exogenous spatial cueing effects. According to this theory, the cost effect (when comparing invalid to neutral cues) arises from attentional suppression resulting from memory encoding of the cue. Conversely, the benefit effect (when comparing valid to neutral cues) is thought to result from a combination of attentional facilitation caused by the cue and encoding-related attentional suppression. This study tests the MEC theory by investigating whether encoding-induced cost increases as the number of cues presented increases. In Experiment 1, participants identified a target letter, which was occasionally preceded by one or three exogenous cues. The results showed that multiple cues resulted in a larger cost effect and a smaller (or even reversed) benefit effect compared to a single cue. This asymmetry between cost and benefit effects was consistently observed across experiments, even when controlling for factors like forward masking and target salience in Experiment 2, or using placeholders as in prior research in Experiment 3. These findings are more consistent with the MEC theory than with traditional attention models. In conclusion, our results provide strong support for the MEC theory, highlighting the importance of both attentional facilitation and encoding-induced suppression in explaining exogenous spatial cueing effects.