Abstract: By exploring the effect of memory load on IOR, 4 experiments systematically tested the hypothesis that the lower component of IOR is free of attention capacity limits, while its counter part is limited by the attention capacity. Experiment 1A and 1B showed that IOR did not disappear with either the semantic or the spatial attention capacity reduction in the spatial-based simple detection tasks. While experiment 2A and 2B showed that the higher component of IOR disappeared with both the semantic and the spatial attention capacity reduction in the color discrimination tasks, so it is limited by the general attention capacity. Meanwhile the results also suggested that the higher component of IOR has much more demands on the attention capacity in the spatial channel than in the semantic channel.

Key words: inhibition of return (IOR), memory load, general attention capacity