Academic journal article Attention, Perception and Psychophysics

A Decisional Account of Subjective Inflation of Visual Perception at the Periphery

Academic journal article Attention, Perception and Psychophysics

A Decisional Account of Subjective Inflation of Visual Perception at the Periphery

Article excerpt

Published online: 24 September 2014

© The Psychonomic Society, Inc. 2014

Abstract Human peripheral vision appears vivid compared to foveal vision; the subjectively perceived level of detail does not seem to drop abruptly with eccentricity. This compelling impression contrasts with the fact that spatial resolution is substantially lower at the periphery. A similar phenomenon occurs in visual attention, in which subjects usually overestimate their perceptual capacity in the unattended periphery.We have previously shown that at identical eccentricity, low spatial attention is associated with liberal detection biases, which we argue may reflect inflated subjective perceptual qualities. Our computational model suggests that this subjective inflation occurs because under the lack of attention, the trial-bytrial variability of the internal neural response is increased, resulting in more frequent surpassing of a detection criterion. In the current work, we hypothesized that the same mechanism may be at work in peripheral vision.We investigated this possibility in psychophysical experiments in which participants performed a simultaneous detection task at the center and at the periphery. Confirming our hypothesis, we found that participants adopted a conservative criterion at the center and liberal criterion at the periphery. Furthermore, an extension of our model predicts that detection bias will be similar at the center and at the periphery if the periphery stimuli are magnified. A second experiment successfully confirmed this prediction. These results suggest that, although other factors contribute to subjective inflation of visual perception in the periphery, such as top-down filling-in of information, the decision mechanism may be relevant too.

Keywords Peripheral vision . Subjective perception . Perceptual decisionmaking . Psychophysics . Signal detection theory

(ProQuest: ... denotes formulae omitted.)

Peripheral vision is limited in resolution and color sensitivity (Mullen, 1991; Noorlander, Koenderink, Den Olden, & Edens 1983; Strasburger, Rentschler, & Jüttner 2011). However, introspectively, peripheral vision does not seem so impaired; it does not seem to be achromatic, blurred, or dark. We experience a sense of vividness and detail outside of the center of gaze, despite a low processing capacity. This somewhat resembles the situation in endogenous spatial attention. For example, in inattentional and change blindness experiments, participants are often surprised at how poorly they detected (changes in) unattended targets, as if they feel they should have seen the targets despite the lack of attention (Simons & Chabris, 1999). It seems like humans overestimate their capacity to see both in the periphery of the visual field and when they are not paying attention. How can we reconcile the apparent contradiction between the high quality of visual experience and the relatively low brain processing capacity for peripheral vision?

We have recently investigated some of these phenomena within the framework of signal detection theory (Green & Swets, 1989;Macmillan & Creelman, 2004).We have previously shown that for stimuli at identical eccentricity, the lack of attention can inflate subjective perception, specifically making detection criterion liberal (i.e., participants' propensity to report detecting a target is higher for unattended stimuli) (Rahnev et al., 2011). These findings have been explained by a signal detection theoretic model, according to which attention both increases the strength of the internal neural response and reduces its trial-bytrial variability (Bressler & Silver, 2010; Pestilli, Carrasco, Heeger, & Gardner 2011; Rahnev et al., 2011; Wyart, Nobre, & Summerfield 2012). This model has since gathered further empirical support from studies using transcranial magnetic stimulation and neuroimaging (Rahnev, Bahdo, De Lange, & Lau 2012; Rahnev, Maniscalco, Luber, Lau, & Lisanby 2012; Rounis, Maniscalco, Rothwell, Passingham, & Lau 2010). …

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