Externally driven attention to internal working memory content

To understand human thought and behaviour, it is vital to understand how internal representations in mind interface with external sensations in the outside world. It is well-established that representations in working memory can involuntarily draw attention towards objects in the outside world with corresponding visual features. Here, we establish that this interface involves a two-way stream by demonstrating that external sensations also involuntarily draw attention to corresponding internal representations in working memory. We demonstrate this across four dedicated experiments in which an unpredictive external stimulus selectively colour-matched working-memory contents, while being completely irrelevant to the working-memory task. We provide converging evidence for this "externally driven internal attention" from tracking attentional dynamics over time through spatial biases in microsaccades as well as from memory performance. We further highlight that engagement with the external stimulus critically shapes the strength of this attentional capture from perception to memory. Together, our findings delineate the properties and consequences of this underexplored attentional pathway, opening novel avenues for research at the interface of perception and memory, and their disorders.