Coarse-to-Fine(r) Automatic Familiar Face Recognition in the Human Brain

Abstract

At what level of spatial resolution can the human brain recognize a familiar face in a crowd of strangers? Does it depend on whether one approaches or rather moves back from the crowd? To answer these questions, 16 observers viewed different unsegmented images of unfamiliar faces alternating at 6 Hz, with spatial frequency (SF) content progressively increasing (i.e., coarse-to-fine) or decreasing (fine-to-coarse) in different sequences. Variable natural images of celebrity faces every sixth stimulus generated an objective neural index of single-glanced automatic familiar face recognition (FFR) at 1 Hz in participants’ electroencephalogram (EEG). For blurry images increasing in spatial resolution, the neural FFR response over occipitotemporal regions emerged abruptly with additional cues at about 6.3–8.7 cycles/head width, immediately reaching amplitude saturation. When the same images progressively decreased in resolution, the FFR response disappeared already below 12 cycles/head width, thus providing no support for a predictive coding hypothesis. Overall, these observations indicate that rapid automatic recognition of heterogenous natural views of familiar faces is achieved from coarser visual inputs than generally thought, and support a coarse-to-fine FFR dynamics in the human brain.

Linguistic and attentional factors – Not statistical regularities – Contribute to word-selective neural responses with FPVS-oddball paradigms

“…The latter was implemented by colour-monitoring of two simultaneous vertical bars left and right from the letter string [see Fig. 1 ; e.g., as used recently in Yan et al., (2022) with face stimuli]. We expect that this alternative task might induce processing of a larger portion of the visual field and thus increase attention to all letters presented, as suggested by studies showing that the size of attentional focus is adjusted to the size of the spatial cue ( Eriksen & St James, 1986 ; Turatto et al., 2000 ) and may improve perceptual identification ( Posner, 1988 ).…”

Linguistic and attentional factors – not statistical regularities – contribute to word-selective neural responses with FPVS-oddball paradigms

“…Taking into account this issue, here we assess the impact of two different tasks requiring either focused or deployed spatial attention. The latter was implemented by colour-monitoring of two simultaneous vertical bars left and right from the letter string (see Figure 1; e.g., as used recently in Yan et al, (2022) with face stimuli). We expect that this alternative task might induce processing of a larger portion of the visual field and thus increase attention to all letters presented, as suggested by studies showing that the size of attentional focus is adjusted to the size of the spatial cue (Eriksen & St James, 1986; Turatto et al, 2000) and may improve perceptual identification (Posner, 1988).…”

The impact of stability in appearance on the development of facial representations

“…Coarse-to-fine processing is ubiquitous in scene, object, and face perception and depends on factors such as the type of categorisation task (e.g., Morrison & Schyns, 2001;Nakashima et al, 2008;Schyns & Oliva, 1994;Yan et al, 2022). Therefore, we propose that the scale of information encoded for a given face depends on its intrinsic characteristics, and on what is diagnostic enough to distinguish it from other faces.…”