Since perceptual and neural face sensitivity is associated with a foveal bias, and neural place sensitivity is associated with a peripheral bias (integration over space), we hypothesized that face perception ability will decline more with eccentricity than place perception ability. We also wanted to examine whether face perception ability would show a left visual field (LeVF) bias due to earlier reports suggesting right hemisphere dominance for faces, or would show an upper or lower visual field bias. Participants performed foveal and parafoveal face and house discrimination tasks for upright or inverted stimuli (≤4°) while their eye movements were monitored. Low-level visual tasks were also measured. The eccentricity-related accuracy reductions were evident for all categories. Through detailed analyses we found (i) a robust face inversion effect across the parafovea, while for houses an opposite effect was found, (ii) higher eccentricity-related sensitivity for face performance than for house performance (via inverted vs. upright within-category eccentricity-driven reductions), (iii) within-category but not across-category performance associations across eccentricities, and (iv) no hemifield biases. Our central to parafoveal investigations suggest that high-level vision processing may be reflected in behavioural performance.

We are constantly exposed to multiple visual scenes, and while freely viewing them without an intentional effort to memorize or encode them, only some are remembered. It has been suggested that image memory is influenced by multiple factors, such as depth of processing, familiarity, and visual category. However, this is typically investigated when people are instructed to perform a task (e.g., remember or make some judgment about the images), which may modulate processing at multiple levels and thus, may not generalize to naturalistic visual behavior. Visual memory is assumed to rely on high-level visual perception that shows a level of size invariance and therefore is not assumed to be highly dependent on image size. Here, we reasoned that during naturalistic vision, free of task-related modulations, bigger images stimulate more visual system processing resources (from retina to cortex) and would, therefore, be better remembered. In an extensive set of seven experiments, naïve participants (n = 182) were asked to freely view presented images (sized 3° to 24°) without any instructed encoding task. Afterward, they were given a surprise recognition test (midsized images, 50% already seen). Larger images were remembered better than smaller ones across all experiments (∼20% higher accuracy or ∼1.5 times better). Memory was proportional to image size, faces were better remembered, and outdoors the least. Results were robust even when controlling for image set, presentation order, screen resolution, image scaling at test, or the amount of information. While multiple factors affect image memory, our results suggest that low- to high-level processes may all contribute to image memory.

Since perceptual and neural face sensitivity is associated with a foveal bias, and neural place sensitivity is associated with a peripheral bias (integration over space), we hypothesized that face perception ability will decline more with eccentricity than place perception ability. We also hypothesized that face perception ability may show an upper visual field (UVF) bias due to the proximity of face-related regions to UVF retinotopic representations, and a left visual field (LeVF) bias due to earlier reports suggesting right hemisphere dominance for faces. Participants performed fovea and parafoveal face discrimination tasks ( 4) while their eye movements were monitored. Additional within-category discrimination performance was measured for houses, inverted faces, shapes and low-level visual acuity. While, as expected, eccentricity-related accuracy reductions were evident for all categories, in contrast to our hypothesis, there was no significant difference between face and house-related accuracy. Furthermore, RTs for houses were significantly faster than for faces at all locations including the fovea. Significant LeVF bias was evident for upright and inverted faces, and face inversion effect was found at all parafoveal eccentricities. Our results suggest that low-level and possibly top-down factors, and not only the face-fovea place-peripheral associations found in high-level visual cortex, influence perceptual performance.Keyword: face, house, parafovea, face inversion effect, eccentricity, upper visual field, lower visual field, right visual field, left visual field

The center-periphery visual field axis guides early visual system organization with enhanced resources devoted to central vision leading to reduced peripheral performance relative to that of central vision (i.e., behavioral eccentricity effect) for most visual functions. The center-periphery organization extends to high-order visual cortex where for example the well-studied face-sensitive fusiform face area (FFA) shows sensitivity to central vision and place-sensitive parahippocampal place area (PPA) shows sensitivity to peripheral vision. As we have recently found that face perception is more sensitive to eccentricity than place perception, here we examined whether these behavioral findings reflect differences in FFA and PPA's sensitivities to eccentricity. We assumed FFA would show higher sensitivity to eccentricity than PPA would, but that both regions' modulation by eccentricity would be invariant to the viewed category. We parametrically investigated (fMRI, n=32) how FFA's and PPA's activations are modulated by eccentricity (less than or equal to 8 degrees) and category (upright/inverted faces/houses) while keeping stimulus size constant. As expected, FFA showed an overall higher sensitivity to eccentricity than PPA. However, both regions' activation modulations by eccentricity were dependent on the viewed category. In FFA a reduction of activation with growing eccentricity ("BOLD eccentricity effect") was found (with different amplitudes) for all categories. In PPA however, there were qualitative modulations of the BOLD eccentricity effect with mild BOLD eccentricity effect for houses but a reverse BOLD eccentricity effect for faces and no modulation for inverted faces. Our results emphasize that peripheral vision investigations are critical to further our understanding of visual processing both quantitatively and qualitatively.

We are constantly exposed to multiple visual scenes, and without intentional effort to memorize or encode them, only some are remembered. It has been suggested that such nonintentional memory is influenced by the depth of processing, but it is unclear whether this applies to visual images. Here we reasoned that bigger images may entail deeper level of processing and will thus be remembered better. In a series of image-viewing experiments we found that larger images were better remembered, image memorability was proportional to image size, faces were better remembered, and outdoors the least. While multiple factors affect image memorability, here we show that under incidental exposure without an encoding task, a basic physical image dimension plays an important role. These results could have significant implications to multiple domains as learning, education, aging, medical care and policies, transport and others.