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The scene-preferring portion of the human ventral visual stream, known as the parahippocampal place area (PPA), responds to scenes and landmark objects, which tend to be large in real-world size, fixed in location, and inanimate. However, the PPA also exhibits preferences for low-level contour statistics, including rectilinearity and cardinal orientations, that are not directly predicted by theories of scene- and landmark-selectivity. It is unknown whether these divergent findings of both low- and high-level selectivity in the PPA can be explained by a unified computational theory. To address this issue, we fit hierarchical computational models of mid-level tuning to the image-evoked fMRI responses of the PPA, and we performed a series of high-throughput experiments on these models. Our findings show that hierarchical encoding models of the PPA exhibit emergent selectivity across multiple levels of complexity, giving rise to high-level preferences along dimensions of real-world size, fixedness, and naturalness/animacy as well as low-level preferences for rectilinear shapes and cardinal orientations. These results reconcile disparate theories of PPA function in a unified model of mid-level visual representation, and they demonstrate how multifaceted selectivity profiles naturally emerge from the hierarchical computations of visual cortex and the natural statistics of images.

Previous research has shown that the components of Chinese characters (e.g., semantic components, phonetic components, and radicals) serve as processing units in reading. One outstanding question concerns the existence of amodal orthographic representations that unify multiple, form-specific character components, similar to the abstract letter identities (ALIs) that unify case-specific letter forms (A/a) in Roman script. Although Chinese does not have case, a subset of semantic radicals have multiple forms (e.g., 氵-水 are both "water" radicals), allowing for a test of the existence of Abstract Radical Identities (ARIs) that unify the multiple forms. In Experiment 1, a visual same-different judgement task was used to detect the presence of ARI representations. Evidence for ARIs was provided by the finding that radical pairs with different forms but the same radical identity were judged to be visually different more slowly than matched pairs of different forms with different radical identities. In Experiment 2, we evaluated ARI effects in real character reading. A lexical decision priming task compared prime-target character pairs containing radicals with the same identity but different forms (e.g., 泄-泉) with matched prime-target character pairs with unrelated radicals (e.g., 無-泉). Inhibitory priming was observed only in the same-identity radical condition compared with the unrelated condition. These combined results provide, for the first time, evidence of format-free representations of orthographic units in Chinese characters-abstract radical identities (ARIs).

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