No other race effect (ORE) for infant face recognition: A memory task

Neural timing of the other-race effect across the lifespan: A review

Face race influences the way we process faces, so that faces of a different ethnic group are processed for identity less efficiently than faces of one's ethnic group - a phenomenon known as the Other-Race Effect (ORE). Although widely replicated, the ORE is still poorly characterized in terms of its development and the underlying mechanisms. In the last two decades, the Event-Related Potential (ERP) technique has brought insight into the mechanisms underlying the ORE and has demonstrated potential to clarify its development. Here, we review the ERP evidence for a differential neural processing of own-race and other-race faces throughout the lifespan. In infants, race-related processing differences emerged at the N290 and P400 (structural encoding) stages. In children, race affected the P100 (early processing, attention) perceptual stage and was implicitly encoded at the N400 (semantic processing) stage. In adults, processing difficulties for other-race faces emerged at the N170 (structural encoding), P200 (configuration processing) and N250 (accessing individual representations) perceptual stages. Early in processing, race was implicitly encoded from other-race faces (N100, P200 attentional biases) and in-depth processing preferentially applied to own-race faces (N200 attentional bias). Encoding appeared less efficient (Dm effects) and retrieval less recollection-based (old/new effects) for other-race faces. Evidence admits the contribution of perceptual, attentional, and motivational processes to the development and functioning of the ORE, offering no conclusive support for perceptual or socio-cognitive accounts. Cross-racial and non-cross-racial studies provided convergent evidence. Future research would need to include less represented ethnic populations and the developmental population.

Event-related brain potential markers of visual and auditory perception: A useful tool for brain computer interface systems

OBJECTIVE

A majority of BCI systems, enabling communication with patients with locked-in syndrome, are based on electroencephalogram (EEG) frequency analysis (e.g., linked to motor imagery) or P300 detection. Only recently, the use of event-related brain potentials (ERPs) has received much attention, especially for face or music recognition, but neuro-engineering research into this new approach has not been carried out yet. The aim of this study was to provide a variety of reliable ERP markers of visual and auditory perception for the development of new and more complex mind-reading systems for reconstructing the mental content from brain activity.

METHODS

A total of 30 participants were shown 280 color pictures (adult, infant, and animal faces; human bodies; written words; checkerboards; and objects) and 120 auditory files (speech, music, and affective vocalizations). This paradigm did not involve target selection to avoid artifactual waves linked to decision-making and response preparation (e.g., P300 and motor potentials), masking the neural signature of semantic representation. Overall, 12,000 ERP waveforms × 126 electrode channels (1 million 512,000 ERP waveforms) were processed and artifact-rejected.

RESULTS

Clear and distinct category-dependent markers of perceptual and cognitive processing were identified through statistical analyses, some of which were novel to the literature. Results are discussed from the view of current knowledge of ERP functional properties and with respect to machine learning classification methods previously applied to similar data.

CONCLUSION

The data showed a high level of accuracy (p ≤ 0.01) in the discriminating the perceptual categories eliciting the various electrical potentials by statistical analyses. Therefore, the ERP markers identified in this study could be significant tools for optimizing BCI systems [pattern recognition or artificial intelligence (AI) algorithms] applied to EEG/ERP signals.

Measuring implicit mental representations related to ethnic stereotypes with ERPs: An exploratory study

The present investigation used ERPs to detect the activation of implicit stereotypical representations associated to different ethnic groups, by means of an implicit paradigm. 285 sentences were presented to 20 Italian Caucasian participants while EEG signals were recorded from 128 scalp sites. Sentences could either violate (Incongruent condition), non-violate (Congruent condition) or be neutral (Neutral condition) with regard to stereotypical concepts concerning non-Caucasian ethnic groups (e.g. Asians, Africans, Arabs). No awareness or judgment about stereotypes was required. Participants were engaged in a fictitious task, ignoring the overall study's purpose. The results showed that Incongruent terminal words elicited a greater anterior N400 response (300-500 ms) compared to Congruent and Neutral words, reflecting a difficulty in integrating the information incongruent with pre-existing stereotypical knowledge. The participant's individual amplitude values of the N400-Difference Wave (Incongruent - Congruent), showed a direct correlation with the individual racism scores obtained at the Subtle and Blatant Prejudice Scale, administered at the end of the experimental session. Intra-cortical sources explaining the N400 involved areas of the social cognition network such as the medial frontal cortex (BA10) and the inferior temporal gyrus (BA20) which are known to support processing of information about other people and impression formation. Moreover, Congruent terminal words evoked a greater P300 response (500-600 ms) compared to the other conditions, possibly reflecting the merging of incoming inputs with anticipated semantic information. A late post-N400 frontal positivity (650-800 ms) was found to be larger to sentences concerning other-race characters (ether congruent or incongruent) compared to sentences involving own-race characters (neutral). The study corroborated the effectiveness of neurophysiological measures to assess implicit complex semantic representations and circumventing social desirability-related problems.