Working memory is a limited-capacity maintenance mechanism that is responsible for processing and keeping information available over a short period of time. Attention, on the other hand, can be defined as a mechanism for the selection and prioritization of elements among many. When attention is focused on a specific piece of information within working memory, this information is assumed to be in the focus of attention. Over the years, the focus of attention has been a much-discussed topic in the field of working memory. Still, there are some characteristics of the focus of attention that remain a topic of debate. Therefore, the current thesis addressed three issues in the literature: (1) whether the accessibility of a representation in the focus of attention is heightened or reduced compared to other representations in working memory, (2) whether a representation in the focus of attention is protected from or (particularly) vulnerable to perceptual interference compared to other representations in working memory, and (3) whether the relation between focusing attention internally (i.e., within working memory) and externally (i.e., toward the environment) is truly asymmetrical. Concerning the first issue, our findings were in line with the literature such that the accessibility of a representation in the focus of attention appears to be heightened by default. However, there can be specific task situations in which this heightened accessibility will be masked or can even turn into reduced accessibility. Concerning the second issue, our findings demonstrated that memory representations are generally not that susceptible to perceptual interference, regardless of whether the representation resides in the focus of attention or not. Concerning the third issue, our findings demonstrated that there is indeed an asymmetrical relation between internal and external attention, which cannot be explained by an imbalance in representational strength of the internal and external information. The theoretical implications of the current thesis contribute to our understanding of the interplay between working memory and attention.