Differential effects of script system acquisition and social immersion experience on face perception

Informelle Berichte zeigten größere Amplituden der durch Gesichter ausgelösten N170 Komponente im Ereigniskorrelierten Potenzial (EKP) bei asiatischen als bei kaukasischen Probanden. Als mögliche Ursache vermutete ich unterschiedliche Erfahrungen mit logographischen bzw. alphabetischen Schriftsystemen (Schriftsystem-Hypothese) oder die verstärkte Exposition mit unbekannten Gesichtern während der Immersion in eine neue soziale oder ethnische Umgebung (soziale Immersions-Hypothese). Zur Überprüfung dieser Hypothesen führte ich zwei kulturvergleichende Studien mit Erwachsenen bzw. Kindern durch. In Studie 1 untersuchte ich einheimische Chinesen und nicht-chinesische Auswärtige in Hongkong und deutsche Einheimische und chinesische Auswärtige in Berlin. Die Auswärtigen an beiden Orten zeigten größere N170 Amplituden auf Gesichter als die Einheimischen. Außerdem zeigten Deutsche, die erst kurze Zeit in Berlin lebten ähnliche Amplituden wie langjährige Einheimische. Insgesamt unterstützt Studie 1 die soziale Immersions-Hypothese, dass die Immersion in eine neue ethnische Umgebung zu einer Vergrößerung der N170 führt. Studie 2 untersuchte die Schriftsystem-Hypothese bei chinesischen und deutschen Erstlesern am Ende der ersten oder zu Beginn des zweiten Schuljahres an ihrem jeweiligen Heimatort. Die Ergebnisse unterstützen die Schriftsystem-Hypothese, dass chinesische Kinder eine größere N170 auf Gesichter zeigen als deutsche. Insgesamt konnte die vorliegende Dissertation zwei neue Einfluss-Faktoren auf das Gesichterverarbeitungs-System nachweisen, das erworbene Schriftsystem (logographische versus alphabetisch) und die Erfahrung sozialer Immersion in eine neue ethnische Umgebung. Diese Effekte zu ganz unterschiedlichen Zeitpunkten der Entwicklung (Kindheit vs. junges Erwachsenen-Alter) zeigen, dass das Gesichterverarbeitungs-System über lange Zeit seine Plastizität behält.Informal reports have shown larger face-elicited N170 component of event-related potential (ERP) in Asians than Caucasians participants. I proposed that different experience with logographic versus alphabetic scripts (script system hypothesis) or by exposure to abundant novel faces during the immersion into a new social and/or ethnic environment (social immersion hypothesis) as a possible cause. To test these hypotheses, I conducted two cross-cultural ERP studies with adults and Children. In Study 1, I examined Chinese locals and non-Chinese foreigners in Hongkong, and German locals and Chinese foreigners in Berlin. It turned out that the foreigners in both locations showed larger N170 amplitudes to faces than the locals. In addition, Germans who had only lived in Berlin for a short time showed similar face N170 amplitudes as long-term Berlin residents. In sum, Study 1 supports the social immersion hypothesis that immersing into a new ethnic environment drives an increase of face N170. Study 2 investigated the scripts system hypothesis in Chinese and German early readers assessed at the end of the first-grade or at the beginning of the second grade in their respective home towns. The findings support the script system hypothesis that Chinese children showed larger face N170 amplitudes than German children. Overall, the present thesis demonstrated two new influencing factors on the face processing system, the acquired script system (logographic vs. alphabetic) and the social immersion experience in a new ethnic environment. More specifically, learning to read a visually complex logographic Chinese script or immersing into an other-ethnic social environment facilitates early perceptual processing of faces. These effects acquired at different stages of development (early childhood versus young adulthood) show that the face processing system retains its plasticity over a long period of time

When is a face a face? Schematic faces, emotion, attention and the N170

Emotional facial expressions provide important non-verbal cues as to the imminent behavioural intentions of a second party. Hence, within emotion science the processing of faces (emotional or otherwise) has been at the forefront of research. Notably, however, such research has led to a number of debates including the ecological validity of utilising schematic faces in emotion research, and the face-selectively of N170. In order to investigate these issues, we explored the extent to which N170 is modulated by schematic faces, emotional expression and/or selective attention. Eighteen participants completed a three-stimulus oddball paradigm with two scrambled faces as the target and standard stimuli (counter-balanced across participants), and schematic angry, happy and neutral faces as the oddball stimuli. Results revealed that the magnitude of the N170 associated with the target stimulus was: (i) significantly greater than that elicited by the standard stimulus, (ii) comparable with the N170 elicited by the neutral and happy schematic face stimuli, and (iii) significantly reduced compared to the N170 elicited by the angry schematic face stimulus. These findings extend current literature by demonstrating N170 can be modulated by events other than those associated with structural face encoding; i.e. here, the act of labelling a stimulus a ‘target’ to attend to modulated the N170 response. Additionally, the observation that schematic faces demonstrate similar N170 responses to those recorded for real faces and, akin to real faces, angry schematic faces demonstrated heightened N170 responses, suggests caution should be taken before disregarding schematic facial stimuli in emotion processing research per se

The Role of Multilingual Script Systems in Face Processing

Becoming multilingual has a broad impact on cognitive abilities, especially visual processing. An important theoretical issue is whether the acquisition of distinct script systems affects face processing in an identical way, or, if not, how this acquisition may exert differential impacts on face processing. By reviewing the existing literature, we propose that Asian participants with the logographic script system differ from Western counterparts with the alphabetic script system in viewing faces. The contribution of the chapter is to identify the possible role of types of script systems in face processing mechanisms and to put forward the research direction in the future with several new methodological efforts

Is human face recognition lateralized to the right hemisphere due to neural competition with left‑lateralized visual word recognition? A critical review

The right hemispheric lateralization of face recognition, which is well documented and appears to be specific to the human species, remains a scientific mystery. According to a long-standing view, the evolution of language, which is typically substantiated in the left hemisphere, competes with the cortical space in that hemisphere available for visuospatial processes, including face recognition. Over the last decade, a specific hypothesis derived from this view according to which neural competition in the left ventral occipito-temporal cortex with selective representations of letter strings causes right hemispheric lateralization of face recognition, has generated considerable interest and research in the scientific community. Here, a systematic review of studies performed in various populations (infants, children, literate and illiterate adults, left-handed adults) and methodologies (behavior, lesion studies, (intra)electroencephalography, neuroimaging) offers little if any support for this reading lateralized neural competition hypothesis. Specifically, right-lateralized face-selective neural activity already emerges at a few months of age, well before reading acquisition. Moreover, consistent evidence of face recognition performance and its right hemispheric lateralization being modulated by literacy level during development or at adulthood is lacking. Given the absence of solid alternative hypotheses and the key role of neural competition in the sensory–motor cortices for selectivity of representations, learning, and plasticity, a revised language-related neural competition hypothesis for the right hemispheric lateralization of face recognition should be further explored in future research, albeit with substantial conceptual clarification and advances in methodological rigor

An investigation into the emotion-cognition interaction and sub-clinical anxiety

This thesis combines behavioural and electrophysiological approaches in the study of the emotion-cognition interaction and sub-clinical anxiety. The research questions addressed in this thesis concern, specifically: the impact of emotion on attention; the interplay between attention and emotion in anxiety;and the cognitive construct of affect. Chapter 1 provides an introduction to emotion research, cognitive models of anxiety and motivates the thesis. Chapter 2 investigates whether affective processing is automatic. More specifically, to elucidate whether facilitated processing of threat in anxiety, evidenced by emotion-related ERP modulations, requires attentional resources. It was previously reported that emotional expression effects on ERP waveforms were completely eliminated when attention was directed away from emotional faces to other task-relevant locations (Eimer et al., 2003). However, Bishop et al. (2004) reported that threat-related stimuli can evoke amygdala activity without attentional engagement or conscious awareness in high-anxious but not low-anxious participants. Spatial attention was manipulated using a similar paradigm as Vuilleumier et al. (2001) and Holmes et al. (2003), to investigate the mechanism underlying the threat-related processing bias in anxiety by examining the influence of spatial attention and trait anxiety levels on established ERP modulations by emotional stimuli. Participants were instructed to match two peripheral faces or two peripheral Landolt squares. The Landolt squares task was selected since this is an attentionally demanding task and would likely consume most, if not all, attention resources. The ERP data did not offer support to the claim that affective stimuli are processed during unattended conditions in high-anxious but not low-anxious participants. Rather, it questions whether a preattentive processing bias for emotional faces is specific to heightened anxiety. This is based on the finding of an enhanced LPP response for threat/happy versus neutral faces and an enhanced slow wave for threat versus neutral faces, neither modulated by the focus of attention for both high and low anxiety groups. Chapter 3 investigated the delayed disengagement hypothesis proposed by Fox and colleagues (2001) as the mechanism underlying the threat-related attentional bias in anxiety. This was done by measuring N2pc and LRP latencies while participants performed an adapted version of the spatial cueing task.Stimuli consisted of a central affective image (either a face or IAPS picture, depending on condition) flanked to the left and right by a letter/number pair. Participants had to direct their attention to the left or right of a central affective image to make an orientation judgement of the letter stimulus. It was hypothesised that if threat-related stimuli are able to prolong attentional processing, N2pc onset should be delayed relative to the neutral condition. However, N2pc latency was not modulated by emotional valence of the central image, for either high or low anxiety groups. Thus, this finding does not provide support for the locus of the threat-related bias to the disengage component of attention. Chapter 4 further investigated the pattern of attentional deployment in the threat-related bias in anxiety. This was done by measuring task-switching ability between neutral and emotional tasks using an adapted version of Johnson’s (in press) attentional control capacity for emotional representations (ACCE) task. Participants performed either an emotional judgement or a neutral judgement task on a compound stimulus that consisted of an affective image (either happy versus fearful faces in the faces condition, or positive versus negative IAPS pictures in the IAPS condition) with a word located centrally across the image (real word versus pseudo-word). Participants scoring higher in trait anxiety were faster to switch from a neutral to a threatening mental set. This improved ability to switch attention to the emotional judgement task when threatening faces are presented is in accordance with a hypervigilance theory of anxiety. However, this processing bias for threat in anxiety was only apparent for emotional faces and not affective scenes, despite the fact that pictures depicting aversive threat scenes were used (e.g., violence, mutilation). This is discussed in more detail with respect to the social significance of salient stimuli. Chapter 5 in a pair of experiments sought to investigate how affect is mentally represented and specifically questions whether affect is represented on the basis of a conceptual metaphor linking direction and affect. The data suggest that the vertical position metaphor underlies our understanding of the relatively abstract concept of affect and is implicitly active, where positive equates with ‘upwards’ and negative with ‘downwards’. Metaphor-compatible directional movements were demonstrated to facilitate response latencies, such that participants were relatively faster to make upward responses to positively-evaluated words and downward responses to negatively-evaluated words than to metaphorincompatible stimulus-response mappings. The finding suggests that popular use of linguistic metaphors depicting spatial representation of affect may reflect our underlying cognitive construct of the abstract concept of valence. Chapter 6 summarises the research in the thesis and implications of the present results are discussed, in particular in relation to cognitive models of anxiety. Areas of possible future research are provided

Literacy acquisition facilitates inversion effects for faces with full-, low-, and high-spatial frequency: evidence from illiterate and literate adults

Previous studies have found that literacy acquisition modulates configural face processing (i.e., holistic and second-order configural processing). However, it remains unclear how literacy acquisition impacts the configural processing indexed by the inversion effect of normal or filtered faces. We asked Chinese illiterate and literate adults to judge whether two sequentially-presented stimuli, including faces, houses (experiment 1), and high- or low-pass filtered faces (experiment 2) were identical. Literate adults outperformed illiterate controls in the upright face and house conditions (experiment 1) and the upright high- and low-pass filtered conditions (experiment 2) but not in the inverted conditions. Notably, the size of an inversion effect (i.e., subtracting inverted accuracy from upright accuracy) was greater among literate adults than that among illiterate adults in both experiments. These findings support that literacy acquisition promotes configural face processing

Multilingualism

This book promotes understanding of multilingualism based on the research efforts at the frontiers with state-of-the-art approaches or novel interdisciplinary perspectives. It addresses issues of the impact of multilingualism on cultural awareness and national identity, gives an overview on how multilingual speakers benefit themselves in learning and communicative competence, and describes the association between multilingualism and media, health, and society

Semantic radical consistency and character transparency effects in Chinese: an ERP study

BACKGROUND: This event-related potential (ERP) study aims to investigate the representation and temporal dynamics of Chinese orthography-to-semantics mappings by simultaneously manipulating character transparency and semantic radical consistency. Character components, referred to as radicals, make up the building blocks used dur...postprin