Top–Down Attention Is Limited Within but Not Between Feature Dimensions

Abstract

In natural vision, processing of spatial and nonspatial features occurs simultaneously; however, the two types of attention in charge of facilitating this processing have distinct mechanisms. Here, we tested the independence of spatial and feature-based attention at different stages of visual processing by examining color-based attentional selection while spatial attention was focused or divided. Human observers attended to one or two of four fields of randomly moving dots presented in both left and right visual hemifields. In the focused attention condition, the target stimulus was defined both by color and location, whereas in the divided attention condition stimuli of the target color had to be attended in both hemifields. Sustained attentional selection was measured by means of steady-state visual evoked potentials elicited by each of the frequency-tagged flickering dot fields. Additionally, target and distractor selection was assessed with ERPs to these stimuli. We found that spatial and color-based attention independently modulated the amplitude of steady-state visual evoked potentials, confirming independent top–down influences on early visual areas. In contrast, P3 amplitudes elicited only by targets and distractors of the attended color were subject to space-based enhancement, suggesting increasing integration of spatial and feature-based selection over the course of perceptual processing.

Parallel attentional facilitation of features and objects in early visual cortex

“…Thus, at least for neural pathways contributing to this cluster, the spread of luminance‐based attention was not restricted by surface boundaries. Similar patterns of attentional coselection were previously shown for combinations of space and color (Adamian, Slaustaite, & Andersen, ; Andersen et al, ; Hayden & Gallant, ) and orientation and color (Andersen et al, , ). Together, these findings strongly suggest that attentional facilitation is applied independently to the different task‐relevant dimensions or features that define the target stimulus, with the multiplicative effects of attention to each feature summing to produce maximal enhancement of the SSVEP to the target feature combination.…”

In search of exogenous feature-based attention

“…In the first study of exogenous FBA (Lin et al, 2011), participants detected the presence (Experiment 1) or discriminated the orientation (Experiment 3) of an oval in an array of uniquely colored circles appearing 200 ms after an uninformative precue was briefly presented. In most studies that manipulate endogenous FBA, a precue has been used as well (e.g., Adamian, Slaustaite, & Andersen, 2019;Fang, Becker, & Liu, 2019;Herrmann, Heeger, & Carrasco, 2012;Ling, Liu, & Carrasco, 2009;Liu et al, 2007b;McMains, Fehd, Emmanouil, & Kastner, 2007;Serences & Boynton, 2007;Störmer & Alvarez, 2014;White & Carrasco, 2011;White et al, 2015). Exogenous SA and exogenous FBA were probed by independently varying the precue's spatial location and color relative to the target ("valid" meaning matching that of the target, "invalid" meaning differing from the target).…”

Steady-state visually evoked potentials and feature-based attention: Pre-registered null results and a focused review of methodological considerations

“…Despite robust SSVEP amplitude (Cohen's d > 5), we observed no credible evidence that the SSVEP response was higher for an attended versus unattended color in either cue condition. Positive control analyses revealed that our lack of SSVEP effect was not due to a complete lack of attention to the attended color: ERP responses (P3) to the targets were modulated by attention as expected (Adamian et al, 2019;Andersen et al, 2013;Andersen, Fuchs, et al, 2011). In light of our inconclusive results, we also performed a focused methodological review of key potential task differences between our work and prior work that may have resulted in our failure to detect the effect of feature-based attention on SSVEP amplitude.…”

“…We included trials where there was only one target or distractor event on that trial, to avoid the possibility of overlap between the two signals. We calculated P3 voltage at electrodes Pz and POz during the time window 450-700 ms after target onset, similar to prior work (Adamian et al, 2019;Andersen et al, 2013;Andersen, Fuchs, et al, 2011).…”