Table 1
A Taxonomy of Attention.
| Controlled Limited resource for controlling attention | Automatic Not resource limited | |||
|---|---|---|---|---|
| Things/Events | Goals/Actions | Things/Events | Goals/Actions | |
| Perceptual | Selective attention to locations, visual objects, events, features. Limited capacity for attending several channels. | Selective attention to ongoing actions, monitoring of action outcomes | Capture of attention by salient stimuli, to stimuli learned to be relevant, or to stimuli in the focus of attention of WM | Capture of attention by errors or unexpected difficulties. |
| Non-Perceptual | Attention to items in WM. Limited capacity for maintenance (“storage”) | Attention to intended actions: Selection of task sets, response selection. Central processing capacity | Involuntary retrieval from long-term memory; intrusive thoughts. | Involuntary retrieval of task sets associated to current stimulus; involuntary selection of response (e.g., Stroop, flanker task) |
[i] Note: Descriptions pertaining to attention as selection/prioritization are printed in regular font; descriptions pertaining to attention as a resource in italics.
Table 2
Open Questions.
| Topic | Question |
|---|---|
| Relation of central attention to WM | Under which circumstances – in particular, for how long into the retention interval – does an attention-demanding processing task compete with maintenance in WM? |
| Relation of perceptual attention and WM | Is the capacity limit of perceptual attention caused by the same limiting factors as the capacity limit of WM? |
| To what extent does perceptual attention to a stimulus lead to its encoding into WM even without the intention to encode it? | |
| The focus of attention in WM | Is the focus of attention in WM the same as the focus of perceptual attention, so that directing attention to a perceived stimulus diverts the focus from its current content in WM, and vice versa? |
| Is the distinction between WM contents in and outside of the focus of attention a qualitative difference or merely a quantitative difference (in degree of memory strength or activation)? | |
| How many distinct items can be selected simultaneously into the focus of attention so that they guide perceptual attention? Some have argued that it is only one item at a time (van Moorselaar, Theeuwes, et al., 2014); others argue for more than one (Hollingworth & Beck, 2016) | |
| The role of neurally active representations | Are all contents of WM represented in a neurally active manner that allows decoding of their contents from neural signals, or only a selected subset of WM contents – maybe only a single item at a time? |
| Are neurally active representations in sensory cortex functionally important for maintenance in WM, or merely an epiphenomenon arising from back-projection of WM representations into sensory areas? | |
| Relation between WM and the control of attention | Under which conditions does a concurrent load on WM impair the control of attention in conflict tasks (e.g., flanker, Stroop tasks)? |
| What causal relation underlies the correlation between WM capacity and measures of attention control (e.g., filtering in visual WM tasks; anti-saccade performance, mind wandering)? |