Non-phase-locked alpha oscillations are involved in spontaneous racial categorization of faces

Creative mindset reduces racial ingroup bias in empathic neural responses

Spontaneous racial categorization of other-race individuals provides a cognitive basis of racial ingroup biases in empathy and prosocial behavior. In two experiments, we investigated whether fostering a creativity mindset reduces racial ingroup biases in empathy and undermines spontaneous racial categorization of other-race faces. Before and after a creative mindset priming procedure that required the construction of novel objects using discreteness, we recorded electroencephalography signals to Asian and White faces with painful or neutral expressions from Chinese adults to assess neural activities underlying racial ingroup biases in empathy and spontaneous racial categorization of faces. We found that a frontal-central positive activity within 200 ms after face onset (P2) showed greater amplitudes to painful (vs. neutral) expressions of Asian compared with White faces and exhibited repetition suppression in response to White faces. These effects, however, were significantly reduced by creative mindset priming. Moreover, the creative mindset priming enhanced the P2 amplitudes to others' pain to a larger degree in participants who created more novel objects. The priming effects were not observed in control participants who copied objects constructed by others. Our findings suggest that creative mindsets may reduce racial ingroup biases in empathic neural responses by undermining spontaneous racial categorization of faces.

Neural representation of perceived race mediates the opposite relationship between subcomponents of self-construals and racial outgroup punishment

Outgroup aggression characterizes intergroup conflicts in human societies. Previous research on relationships between cultural traits and outgroup aggression behavior showed inconsistent results, leaving open questions regarding whether cultural traits predict individual differences in outgroup aggression and related neural underpinnings. We conducted 2 studies to address this issue by collecting self-construal scores, EEG signals in response to Asian and White faces with painful or neutral expressions, and decisions to apply electric shocks to other-race individuals in a context of interracial conflict. We found that interdependent self-construals were well explained by 2 subcomponents, including esteem for group (EG) and relational interdependence (RI), which are related to focus on group collectives and harmonious relationships, respectively. Moreover, EG was positively associated with the decisions to punish racial outgroup targets, whereas RI was negatively related to the decisions. These opposite relationships were mediated by neural representations of perceived race at 120-160 ms after face onset. Our findings highlight the multifaceted nature of interdependent self-construal and the key role of neural representations of race in mediating the relationships of different subcomponents of cultural traits with racial outgroup punishment decisions in a context of interracial conflict.

Parametric separation of phase-locked and non-phase-locked activity

Brain dynamics recorded via electroencephalography (EEG) is conceptualized as a sum of two components: "phase-locked" and "non-phase-locked" to the stimulus. Phase-locked activity is often implicitly studied as event-related potentials (ERPs), and the trial-averaged estimates-evoked potentials (EP) considered both time-locked and phase-locked to the stimulus. The non-phase-locked activity, on the other hand, refers to an increase in power in a narrow band or broadband frequencies in the signal emerging at variable phases from stimulus initiation. Both components are understood to stem from different neuronal mechanisms; hence, accurately characterizing them is of immense importance to neuroscientific studies. Here, we discuss the drawbacks of currently used methods to separate the phase-locked and non-phase-locked activity and propose a novel concurrent phaser method (CPM) that simultaneously decomposes the two components. First, we establish that the single-trial separation of phase-locked and non-phase-locked power is an ill-posed problem. Second, using simulations where ground truth validation is possible, we elucidate how the estimation of non-phase-locked power gets biased by phase-locked power in the state-of-the-art averaging method and ways to resolve the issue using CPM. Next, we use two experimental EEG datasets-audio oddball and auditory steady-state responses (ASSR) to show that empirical signal-to-noise estimates warrant the usage of CPM to separate phase-locked and non-phase-locked activity. Thus, using ground truth validation from simulations and demonstration in real experimental scenarios, the efficacy of the proposed CPM is established.NEW & NOTEWORTHY Parametric models for estimation of phase-locked and non-phase-locked brain signals reveals how estimation of non-phase-locked component is biased by the variability of phase-locked component and at the level of single trial becomes an ill-posed problem. Furthermore, the modeling framework delimits the boundaries where traditional averaging approach can be trusted to estimate the phase-locked and non-phase-locked components.