BackgroundEye movement strategies employed by humans to identify conspecifics are not universal. Westerners predominantly fixate the eyes during face recognition, whereas Easterners more the nose region, yet recognition accuracy is comparable. However, natural fixations do not unequivocally represent information extraction. So the question of whether humans universally use identical facial information to recognize faces remains unresolved.Methodology/Principal FindingsWe monitored eye movements during face recognition of Western Caucasian (WC) and East Asian (EA) observers with a novel technique in face recognition that parametrically restricts information outside central vision. We used ‘Spotlights’ with Gaussian apertures of 2°, 5° or 8° dynamically centered on observers' fixations. Strikingly, in constrained Spotlight conditions (2° and 5°) observers of both cultures actively fixated the same facial information: the eyes and mouth. When information from both eyes and mouth was simultaneously available when fixating the nose (8°), as expected EA observers shifted their fixations towards this region.Conclusions/SignificanceSocial experience and cultural factors shape the strategies used to extract information from faces, but these results suggest that external forces do not modulate information use. Human beings rely on identical facial information to recognize conspecifics, a universal law that might be dictated by the evolutionary constraints of nature and not nurture.

Eye movement data analyses are commonly based on the probability of occurrence of saccades and fixations (and their characteristics) in given regions of interest (ROIs). In this article, we introduce an alternative method for computing statistical fixation maps of eye movements-iMap-based on an approach inspired by methods used in functional magnetic resonance imaging. Importantly, iMap does not require the a priori segmentation of the experimental images into ROIs. With iMap, fixation data are first smoothed by convolving Gaussian kernels to generate three-dimensional fixation maps. This procedure embodies eyetracker accuracy, but the Gaussian kernel can also be flexibly set to represent acuity or attentional constraints. In addition, the smoothed fixation data generated by iMap conform to the assumptions of the robust statistical random field theory (RFT) approach, which is applied thereafter to assess significant fixation spots and differences across the three-dimensional fixation maps. The RFT corrects for the multiple statistical comparisons generated by the numerous pixels constituting the digital images. To illustrate the processing steps of iMap, we provide sample analyses of real eye movement data from face, visual scene, and memory processing. The iMap MATLAB toolbox is editable and freely available for download online (www.unifr.ch/psycho/ibmlab/).Keywords Eye movements . Statistical fixation maps . Data-driven analyses . Random field theory . Matlab toolboxThe human visual system is equipped with the most sophisticated machinery to effectively adapt to the visual world. Where, when, and how human eyes are moved to gather information to adapt to the visual environment has been a question that has fascinated scientists for more than a century. Javal (1879) coined the term saccade to describe the rapid movement of the eyes produced during reading, an oculomotor phenomenon identified by Hering (1879) and Lamare (1892) during this period. However, a comprehensive sense of the very nature of those ballistic movements, a description of the use of fixations to gather the information relevant to solving the task at hand, and the scientific definition of saccades came with Dodge (1916) and the development of photographic techniques for recording corneal reflections. This novel recording approach paved the way for the scientific study of eye movements (see Wade, Tatler, & Heller, 2003). Buswell (1935) published the first systematic study on How People Look at Pictures: A Study of The Psychology of Perception in Art. Buswell observed that trained and untrained artists deployed similar fixation patterns to analyze paintings. All observers shared similar oculomotor behavior, deploying initial short fixations over the main features of the paintings, which were subsequently followed by a series of longer fixations. Interestingly, when fixations were collapsed across observers, they highlighted areas containing salient or diagnostic parts of the images. Critically, these observations revealed that eye moveme...

A word's frequency of occurrence and its predictability from a prior context are key factors that determine how long the eyes remain on that word in normal reading. Past reaction-time and eye movement research can be distinguished by whether these variables, when combined, produce interactive or additive results, respectively. Our study addressed possible methodological limitations of prior experiments. Initial results showed additive effects of frequency and predictability. However, we additionally examined launch site (the distance from the pre-target fixation to the target word) to index the extent of parafoveal target processing. Analyses revealed both additive and interactive frequency × predictability effects on target fixations, with the nature of the interaction depending on the quality of the parafoveal preview. Target landing position and pre-target fixation time were also considered. Results were interpreted in terms of models of language processing and eye movement control. Our findings with respect to parafoveal preview and fixation time constraints aim to help parameterize eye movement behavior. Keywords:reading; eye movements; word frequency; contextual predictability; launch site; landing position; parafoveal-on-foveal processing; additive; interactive; models of eye movement control 3 Two key variables that influence the amount of time a reader spends fixating a word in reading are its frequency of occurrence and its predictability from the prior text. Past research has been somewhat equivocal on whether these two factors are additive or interactive. Our study explores the relationship between frequency and predictability on eye movement behavior during normal reading. In contrast to prior studies, we additionally examine the effect of launch site, that is, the distance between the target word and the location of the pre-target fixation. Launch distance can determine how much information is obtained from the target parafoveally, prior to its subsequent fixation. We believe this approach provides a more dynamic account of how frequency and predictability interact as a function of the reader's initial viewing distance.During normal reading, a series of discrete eye fixations are made through text and individual word meanings are activated and integrated on-line into a developing discourse representation. Measuring eye movements during fluent reading is an established technique that is sensitive to on-line perceptual and cognitive aspects of lexical processing (Rayner, 1998;Sereno & Rayner, 2003). As a response measure, fixation time possesses certain advantages over traditional behavioral measurements -namely, there is no secondary task involving overt decisions, and fixation times are shorter than, for example, naming or lexical decision latencies.Eye movement reading research over the past three decades has revealed that reading behavior can be accurately assessed by measuring the position, duration, and sequence of eye fixations in text (for reviews, see Rayner, 1998;Rayner, 2009).One v...

Culture affects the way people move their eyes to extract information in their visual world. Adults from Eastern societies (e.g., China) display a disposition to process information holistically, whereas individuals from Western societies (e.g., Britain) process information analytically. In terms of face processing, adults from Western cultures typically fixate the eyes and mouth, while adults from Eastern cultures fixate centrally on the nose region, yet face recognition accuracy is comparable across populations. A potential explanation for the observed differences relates to social norms concerning eye gaze avoidance/engagement when interacting with conspecifics. Furthermore, it has been argued that faces represent a ‘special’ stimulus category and are processed holistically, with the whole face processed as a single unit. The extent to which the holistic eye movement strategy deployed by East Asian observers is related to holistic processing for faces is undetermined. To investigate these hypotheses, we recorded eye movements of adults from Western and Eastern cultural backgrounds while learning and recognizing visually homogeneous objects: human faces, sheep faces and greebles. Both group of observers recognized faces better than any other visual category, as predicted by the specificity of faces. However, East Asian participants deployed central fixations across all the visual categories. This cultural perceptual strategy was not specific to faces, discarding any parallel between the eye movements of Easterners with the holistic processing specific to faces. Cultural diversity in the eye movements used to extract information from visual homogenous objects is rooted in more general and fundamental mechanisms.

Face recognition is not rooted in a universal eye movement information-gathering strategy. Western observers favor a local facial feature sampling strategy, whereas Eastern observers prefer sampling face information from a global, central fixation strategy. Yet, the precise qualitative (the diagnostic) and quantitative (the amount) information underlying these cultural perceptual biases in face recognition remains undetermined. To this end, we monitored the eye movements of Western and Eastern observers during a face recognition task, with a novel gaze-contingent technique: the Expanding Spotlight. We used 2° Gaussian apertures centered on the observers’ fixations expanding dynamically at a rate of 1° every 25 ms at each fixation – the longer the fixation duration, the larger the aperture size. Identity-specific face information was only displayed within the Gaussian aperture; outside the aperture, an average face template was displayed to facilitate saccade planning. Thus, the Expanding Spotlight simultaneously maps out the facial information span at each fixation location. Data obtained with the Expanding Spotlight technique confirmed that Westerners extract more information from the eye region, whereas Easterners extract more information from the nose region. Interestingly, this quantitative difference was paired with a qualitative disparity. Retinal filters based on spatial-frequency decomposition built from the fixations maps revealed that Westerners used local high-spatial-frequency information sampling, covering all the features critical for effective face recognition (the eyes and the mouth). In contrast, Easterners achieved a similar result by using global low-spatial-frequency information from those facial features. Our data show that the face system flexibly engages into local or global eye movement strategies across cultures, by relying on distinct facial information span and culturally tuned spatially filtered information. Overall, our findings challenge the view of a unique putative process for face recognition.

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This experiment employed the boundary paradigm during sentence reading to explore the nature of early phonological coding in reading. Fixation durations were shorter when the parafoveal preview was the correct word than when it was a spelling control pseudoword. In contrast, there was no significant difference between correct word and pseudohomophone previews. These results suggest that the phonological codes are assembled before word fixation and are used for lexical access. Moreover, there was evidence that orthographic codes influence the activation of word meaning. We found that fixation durations were shorter for orthographically similar parafoveal previews, and this orthographic priming effect is limited to pseudohomophones. Thus, it seems that both the orthographic and the phonological similarities of the parafoveal preview to the target play a part in the facilitative effects of the preview.

Perception and eye movements are affected by culture. Adults from Eastern societies (e.g. China) display a disposition to process information holistically, whereas individuals from Western societies (e.g. Britain) process information analytically. Recently, this pattern of cultural differences has been extended to face processing. Adults from Eastern cultures fixate centrally towards the nose when learning and recognizing faces, whereas adults from Western societies spread fixations across the eye and mouth regions. Although light has been shed on how adults can fixate different areas yet achieve comparable recognition accuracy, the reason why such divergent strategies exist is less certain. Although some argue that culture shapes strategies across development, little direct evidence exists to support this claim. Additionally, it has long been claimed that face recognition in early childhood is largely reliant upon external rather than internal face features, yet recent studies have challenged this theory. To address these issues, we tested children aged 7-12 years of age from the UK and China with an old ⁄ new face recognition paradigm while simultaneously recording their eye movements. Both populations displayed patterns of fixations that were consistent with adults from their respective cultural groups, which 'strengthened' across development as qualified by a pattern classifier analysis. Altogether, these observations suggest that cultural forces may indeed be responsible for shaping eye movements from early childhood. Furthermore, fixations made by both cultural groups almost exclusively landed on internal face regions, suggesting that these features, and not external features, are universally used to achieve face recognition in childhood.