rincipal component analysis of behavioural individual differences suggests that articular aspects of visual working memory may relate to specific aspects of ttention

The previously separate literatures on visual attention and on visual working memory are converging, with growing interest in how visual attention may relate to visual short-term memory, as exemplified by this special issue. We report exploratory analysis of how individual behavioural differences in separable aspects of attention may relate to particular aspects of visual working memory. Previous work with the Attention Network Test (ANT; Fan, McCandliss, Sommer, Raz, & Posner, 2002) proposed that it can measure three distinct aspects of attention: alerting, spatial orienting, plus executive control of response competition. We implemented the ANT in 50 healthy young adults, who also underwent a behavioural battery of visual working memory (WM) tests. These visual WM tests were all variations on recent paradigms, used here with the aim of measuring potential individual differences in visual WM capacity; WM precision; or WM distractor-filtering. Principal component analysis of the behavioural ndividual differences dataset revealed three main components. Interestingly, each component paired one aspect of ANT scores together with one aspect of WM scores, in terms of the strongest loadings. WM capacity loaded with ANT alerting; WM precision with ANT orienting; and WM filtering with ANT executive control. These results suggest that visual WM may involve separate component processes, and that different aspects of attention relate to different aspects of visual WM, in terms of behavioural individual differences. We ern in indiv discuss the observed patt potential neural bases of Since James (1890) speculated on the possible distinction etween primary (short-term) memory versus secondary (longerm) memory, there has been over a century of research into rocesses underlying short-term or “working” memory, WM (see addeley, 1986, 2007). WM is considered to involve active mainenance of recently encountered stimuli over short delays, and s thought to have limited capacity. It is widely held that WM s important for many aspects of daily life that involve active, hort-term, selective retention. Numerous studies have indicated hat WM abilities may relate to cognitive aptitude more generally, ncluding reasoning and fluid intelligence (Engle, Kane, & Tuholski, Please cite this article in press as: Machizawa, M. G., & Driver, J. ences suggests that particular aspects of visual working memory may doi:10.1016/j.neuropsychologia.2010.11.032 999), reading ability (De Jong, 1998) or scholastic success (Cowan t al., 2005), though the complex relationship between WM and spects of intelligence requires further research (see Conway, Kane, Engle, 2003). ∗ Corresponding author at: 17 Queen Square, Alexandra House, London WC1N AR, United Kingdom. Tel. : +44 0207 7679 1123; fax: +44 0207 7916 8517. E-mail address: m.machizawa@ucl.ac. uk (M.G. Machizawa). 028-3932/$ – see front matter © 2010 Elsevier Ltd. All rights reserved. oi:10.1016/j.neuropsychologia. 2010.11. 032 relation to current issues and with respect to possible future work on the idual differences in the distinct components. © 2010 Elsevier Ltd. All rights reserved. Here we focus on visual WM in particular. It has frequently been suggested that WM capacity for simple visual stimuli such as oriented bars, colour patches or symbols might average around 3–4 items (e.g. Cowan, 2001; Luck & Vogel, 1997; Vogel & Machizawa, 2004). But this remains debated, with other suggestions being made. Visual WM might involve capacity being flexibly allocated, to fewer items with more precision, or to more items with less precision (e.g. Bays & Husain, 2008; see also Bays, Wu, & Husain, in this issue). It has also been proposed that apparent differences in WM capacity between individuals might primarily reflect their ability to prevent distractor stimuli from entering WM (e.g. McNab & Klingberg, 2008; Vogel, McCollough & Machizawa, 2005). Recent work has sought not only to identify psychological subprocesses contributing to WM (e.g. see Baddeley, 1986, 2007; Engle, 2002), but also to relate these to brain regions and underlying neuPrincipal component analysis of behavioural individual differrelate to specific aspects of attention. Neuropsychologia (2011), ral mechanisms (e.g. McNab & Klingberg, 2008; Vogel et al., 2005; Xu & Chun, 2009). Space limitations here preclude a fully exhaustive review of this large and expanding field of research (see Jonides et al., 2008, for one overview, as well as the other articles in this issue). Instead we focus here on three recent developments that