2.1 Introduction

In an increasingly complex world where people routinely handle large amounts of information, individuals are constantly challenged to manage and effectively use the information that they are responsible for. While email is the canonical example of an information overloading application, other well-known personal information management (PIM) applications and tasks cited in earlier chapters of this book include maintaining addresses and contacts, scheduling, and organizing the various documents and bookmarks that one is interested in. Not surprisingly, there are individual differences (ID) in how, and how well, people cope with the challenge of personal information management. This greatly complicates any scientific analysis of PIM behavior. Thus, in addition to the evaluation methods discussed in the previous chapter, researchers and designers need to consider when and how individual differences should be included within parsimonious interpretations and explanations of PIM behavior. In this chapter, we propose an approach where differences between individuals are considered last, after the influences of the environment and the task context have first been considered, and after group difference (e.g., between job classifications) have been investigated. We believe that this is a logical way to proceed—much as if we were observing an ant walking over sand-dunes (cf. Simon 1996)—since we should not ascribe complexities to an individual if they can instead be explained as due to properties of the environment. The goal of this chapter will be to review and synthesize some of the key findings in how PIM behavior differs between individuals. Some of the reasons why these differences occur and what can be done about them will also be discussed.