Object detection in natural scenes: Independent effects of spatial and category-based attention

Abstract

Humans are remarkably efficient in detecting highly familiar object categories in natural scenes, with evidence suggesting that such object detection can be performed in the (near) absence of attention. Here we systematically explored the influences of both spatial attention and category-based attention on the accuracy of object detection in natural scenes. Manipulating both types of attention additionally allowed for addressing how these factors interact: whether the requirement for spatial attention depends on the extent to which observers are prepared to detect a specific object category—that is, on category-based attention. The results showed that the detection of targets from one category (animals or vehicles) was better than the detection of targets from two categories (animals and vehicles), demonstrating the beneficial effect of category-based attention. This effect did not depend on the semantic congruency of the target object and the background scene, indicating that observers attended to visual features diagnostic of the foreground target objects from the cued category. Importantly, in three experiments the detection of objects in scenes presented in the periphery was significantly impaired when observers simultaneously performed an attentionally demanding task at fixation, showing that spatial attention affects natural scene perception. In all experiments, the effects of category-based attention and spatial attention on object detection performance were additive rather than interactive. Finally, neither spatial nor category-based attention influenced metacognitive ability for object detection performance. These findings demonstrate that efficient object detection in natural scenes is independently facilitated by spatial and category-based attention.

Preparatory attention in visual cortex

“…The beneficial influence of content-based attention appears to reflect a general mechanism that can operate at different levels of abstractness of stimulus content, from simple stimulus features to basic-level object categories and even superordinate categories. 30,31 These findings demonstrate that content-based attention can influence performance in even the most basic perceptual tasks, similar to spatial attention. This does not necessarily imply that content-based and spatial attention rely on identical cognitive and neural mechanisms.…”

“…For example, Stein and Peelen provided participants with prior information about the orientation of an upcoming grating through a word cue (e.g., “horizontal”) and found that accuracy in detecting and localizing briefly presented, low‐contrast targets was better when the orientation of the target matched the word cue, even though orientation was irrelevant to the detection task. The beneficial influence of content‐based attention appears to reflect a general mechanism that can operate at different levels of abstractness of stimulus content, from simple stimulus features to basic‐level object categories and even superordinate categories …”

“…In these tasks, attention is unlikely to be directed to a specific low-level feature, yet detection is highly efficient when preparatory attention is available. 31,95,96 One possibility is that, through experience, neurons in the high-level visual cortex have become selectively tuned to these object categories. 97,98 Alternatively, experience may increase the efficiency of attending to a set of features that together are diagnostic of the presence of the category, 10 thus reflecting efficient parallel attentional guidance by multiple separately represented features.…”

Waving goodbye to contrast: Self-generated hand movements attenuate visual sensitivity

“…Prospective investigations are also required to examine more precisely how our findings generalise over different categories of stimuli or stimulus feature differentiation. It has been shown that these aspects can interact with attention and metacognition (Stein & Peelen, 2017;Matthews et al, 2018). In addition, the precise influence of evidence-reliability remains to be elucidated in more extensive work as it has also been shown to affect confidence judgments and metacognition (Boldt, De Gardelle & Yeung, 2017;Bang & Fleming, 2018;Denison & al., 2018).…”

Spatial attention follows category-based attention during naturalistic visual search: evidence from MEG decoding

“…Behavioral studies have shown that participants may not be able to localize object categories in natural scenes that have nonetheless been detected (Evans and Treisman, 2005). Others have argued that the detection of familiar object categories may not even require spatial attention at all (Li et al, 2002; see also Stein and Peelen, 2017). These findings suggest that spatially-global category-based attention may be sufficient for detecting target-diagnostic features.…”