 Although the psychological debates about salience maps are ongoing, an argument against pure spotlight views can also be made on more traditional, phenomenological grounds. A pure spotlight theory, according to which attention is always allocated on the basis of location, seems unable to account for the sort of case that Hermann von Helmholtz and William James were concerned with (see section  1.5).  There is, as their example suggests, a difference between attending to the pitch of a note and attending to its timbre, or to its overtones. This difference in attention does not seem to correspond to any difference in the location attended. Nor does any purely location-based theory of attention allocation seem able to account for the sort attention that one must pay in order to perform a time-based task, such as finding out which of a group of shapes appears on screen for longest. Such temporal aspects of attention have been a relatively late addition to the psychological research agenda (see the papers collected in Nobre and Coull, 2010). The research concerning them is beginning to reveal a diverse range of effects, with a range of similarly diverse neural underpinnings (Nobre and van Ede, 2018). Some philosophical work has been devoted to the exploration of these temporal aspects of attention (see Phillips, 2011), but it is work that has tended to address questions that further our understanding of the experience and perception of time, without attempting to contribute directly to our philosophical understanding of attention itself (see the entry on  The Experience and Perception of Time).