Rapid Attentional Selection of Non-native Stimuli despite Perceptual Narrowing

Abstract

Visual experiences increase our ability to discriminate environmentally relevant stimuli (native stimuli, e.g., human faces) at the cost of a reduced sensitivity to irrelevant or infrequent stimuli (non-native stimuli, e.g., monkey/ape faces)—a developmental progression known as perceptual narrowing. One possible source of the reduced sensitivity in distinguishing non-native stimuli (e.g., one ape face vs. another ape face) could be underspecified attentional search templates (i.e., working memory representations). To determine whether perceptual narrowing stems from underspecified attentional templates for non-native exemplars, this study used ERP (the N2pc component) and behavioral measures in a visual search task, where the target was either an exemplar (e.g., a specific ape face) or a category (e.g., any ape face). The N2pc component, an ERP marker of early attentional selection emerging at 200 msec poststimulus, is typically modulated by the specificity of the target and, therefore, by the attentional template—the N2pc is larger for specific items versus categories. In two experiments using both human and ape faces (i.e., native and non-native stimuli), we found that perceptual narrowing affects later response selection (i.e., manual RT and accuracy), but not early attentional selection relying on attentional templates (i.e., the N2pc component). Our ERP results show that adults deploy exemplar level attentional templates for non-native stimuli (as well as native stimuli), despite poor downstream behavioral performance. Our findings suggest that long-term previous experience with reduced exemplar level judgments (i.e., perceptual narrowing) does not appear to eliminate early attentional selection of non-native exemplars.

A neural signature of rapid category-based target selection as a function of intra-item perceptual similarity, despite inter-item dissimilarity

“…However, a number of studies document discrepancies between neural and behavioral results (Haynes & Rees, 2005; He et al, 1996). Recent N2pc research suggests that behavioral responses are modulated by additional factors that do not affect the N2pc component (Wu et al, 2015). In Wu et al, participants had slower reaction times when selecting non-native targets (ape faces with which we tend to have little experience) compared to native targets (human faces with which we have a lifetime of experience).…”

“…For each trial, a search array displayed for 200 ms contained two black line-drawn aliens on a white background (Figure 3; see Eimer, 1996 and Wu et al, 2015 for examples of 2-item N2pc visual search). The duration was chosen to minimize eye-movements, which interfere with the N2pc ERP.…”

“…We used the following criteria for artifact rejection for the entire epoch: horizontal EOG exceeding ± 25 μV, vertical EOG exceeding ± 60 μV, all other channels exceeding ± 80 μV. Including only correct trials, the average percentage of trials retained per participant after artifact rejection was 74%, the typical amount in previous studies (e.g., Wu et al, 2015). Mean N2pc amplitudes were obtained at lateral posterior electrodes PO7 and PO8 between 220ms and 340ms after search array onset (Wu et al, 2013).…”

“…In summary, while attentional templates can contain a single low-level target-defining feature (e.g., one orientation, shape, or color) or one whole object (see Olivers et al, 2011), findings by Nako et al (2014a) show that attentional templates also can consist of higher-level abstract features, such as categories composed of multiple objects (see additional evidence in Wu et al, 2013; Wu et al, 2015). Thus, grouping multiple features into one object and multiple objects into one category may be an effective strategy for maximizing the information content of one attentional template and overcoming attentional limitations during search.…”

“…As a result, the non-linear fall off of the N2pc with increasing set-size can be used as diagnostic of a category-level attentional template. Importantly, the N2pc is modulated by grouping exemplars into a category, not by task difficulty (Wu et al, 2015). …”