Abstract
Recent investigations that suggest selective attention (SA) is dependent on top-down control mechanisms lead to the expectation that individuals with high executive capacity (EC) would exhibit more robust neural indices of SA. This prediction was tested by using event-related potentials (ERPs) to examine differences in markers of information processing across 25 subjects divided into two groups based on high vs. average EC, as defined by neuropsychological test scores. Subjects performed an experimental task requiring SA to a specified color. In contrast to expectation, individuals with high and average EC did not differ in the size of ERP indices of SA: the anterior Selection Positivity (SP) and posterior Selection Negativity (SN). However, there were substantial differences between groups in markers of subsequent processing, including the anterior N2 (a measure of attentional control) and the P3a (an index of the orienting of attention). EC predicted speed of processing at both early and late attentional stages. Individuals with lower EC exhibited prolonged SN, P3a, and P3b latencies. However, the delays in carrying out SA operations did not account for subsequent delays in decision making, or explain excessive orienting and reduced attentional control mechanisms in response to stimuli that should have been ignored. SN latency, P3 latency, and the size of the anterior N2 made independent contributions to the variance of EC. In summary, our findings suggest that current views regarding the relationship between top-down control mechanisms and SA may need refinement.
Highlights
Previous models of attentional function viewed selective attention (SA) and working memory as being mediated by separate neurocognitive systems (Kahneman, 1973; Hirst, 1986; Wijers et al, 1989; Kok, 2000; Luck et al, 2000)
The inclusion of a color-neutral condition allowed for further evaluation of whether the expected difference between high and average capacity individuals in the Selection Positivity (SP) and Selection Negativity (SN) was primarily explained by the diminished ability of average capacity individuals to inhibit neural activity under the Ignore relative to the neutral attention task (Neutral) condition
We expanded upon previous research by deriving an estimate of executive capacity (EC) based on a set of neuropsychological tests rather than performance on the particular experimental task employed, and by examining the relationship between individual differences in EC and traditional event-related potential (ERP) measures of both early SA and later processing
Summary
Previous models of attentional function viewed selective attention (SA) and working memory as being mediated by separate neurocognitive systems (Kahneman, 1973; Hirst, 1986; Wijers et al, 1989; Kok, 2000; Luck et al, 2000). Investigators have argued that the top-down control functions of WM allow individuals to actively maintain current stimulus processing priorities, which facilitates the processing of information most critical to task demands (Desimone and Duncan, 1995; Lavie et al, 2004; Sawaki and Katayama, 2008; Rutman et al, 2010) Within this framework, SA and WM are viewed as dependent on a shared pool of limited processing resources. Vogel et al (2005) divided subjects into high vs low WM capacity groups and found that the low capacity group was less able to prevent the encoding and storage of distracter items, as measured electrophysiologically by what was labeled contralateral delay activity They suggested that WM capacity strongly influences the efficiency of SA
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