Imagery and overflow: We see more than we report

The question of whether our conscious experience is rich or sparse remains an enduring controversy in philosophy. The “overflow” account argues that perceptual consciousness is far richer than cognitive access: when perceiving a complex scene, subjects see more than they can report. This paper draws on aphantasia (the condition of absent voluntary imagery) to propose a new argument in favor of overflow. First, it shows that opponents of overflow explain subjects’ performance in a change detection paradigm by appealing to a type of “internal imagery.” Second, it provides empirical evidence to demonstrate that aphantasics are incapable of generating this imagery. However, aphantasics perform equally well in this task; and so the no-overflow account fails to explain their performance. This means that proponents of this view are committed to an unsupported view of perception.