Spider phobia is one of the most common types of specific phobias that can be effectively treated with exposure therapy. During exposure therapy, the patients experience encounters with spiders in a safe environment. Exposure sessions are traditionally performed face-to-face and modulate the intensity of the experience by varying the distance to the feared animal. More recently, immersive virtual reality (VR) has been introduced as an alternative treatment option that allows for novel ways of modulating the experienced intensity. In 23 participants (M age = 31.00), we tested whether embodiment with a virtual arm, or visual realism of a spider, influenced self-rated anxiety and pupillary responses as the spider crawled over the virtual arm. Embodiment was manipulated by asking participants to place their arm congruently (high embodiment) or incongruently (low embodiment) with the virtual arm, and visual realism was manipulated by changing the spider's movement, texture and colour to be either realistic or simple. Differences in pupil size between conditions were analysed with permutation testing, and anxiety ratings with repeated measures ANOVA. Results showed that embodiment with the VR arm increased pupil-size and self-rated anxiety (p < .001). In contrast, increased realism of the spider had no effect on pupil-size or anxiety ratings. Findings support that embodiment in immersive VR intensifies emotional experiences, which could have implications for controlling arousal and anxiety within VR exposure therapy settings.

In everyday interactions, social evaluative feedback can elicit defensive responses that vary across individuals, underscoring the need to clarify the psychophysiological mechanisms underlying this variability. This study examined the cardiac correlates of defensive responses to social feedback, focusing on how cardiac activity reflects individual differences in self-protective behavior. Participants completed a mobile-based reciprocal artwork evaluation task while cardiac activity was continuously monitored via photoplethysmography using a wearable smartwatch. During the task, participants received positive, negative, or neutral feedback from partners and subsequently evaluated the creativity of the partner's artwork, indexing defensive behavioral responses. Feedback-evoked heart rate responses were analyzed using temporal intersubject representational similarity analysis (IS-RSA) to assess how dynamic cardiac similarity patterns related to individual differences in behavioral tendencies across feedback conditions. Results revealed that social feedback systematically influenced subsequent evaluations of the partner's artwork. Negative feedback elicited transient heart rate deceleration, whose magnitude was inversely associated with resting heart rate variability. IS-RSA further revealed that individuals who made more favorable judgments following positive feedback exhibited greater intersubject cardiac similarity during the early post-feedback period. Follow-up group analyses indicated that this convergence reflected transient heart rate deceleration among individuals with stronger behavioral bias. Together, these findings elucidate the physiological basis of self-protective bias in social contexts and highlight the role of individual psychophysiological variability.

Recognizing a familiar stimulus is essential to our everyday life. Recent studies revealed details of the nature of the neural dynamics of familiarity representations for human faces. Still, we know relatively little on how different familiar and non-familiar stimulus processing is for non-human face stimuli. Here we report the results of an EEG study, examining the neural dynamics of personally familiar human and dog faces. Participants viewed highly variable images of personally familiar and unfamiliar faces as well as of their own dogs and breed-matched unfamiliar ones. Multivariate pattern analyses were used to examine the time course of differential processing of familiar and unfamiliar human and dog face stimuli. Time-resolved classification revealed that familiarity is decodable from the EEG data from 90 ms onwards, similarly for human and non-human faces. The temporal dynamics were very similar for these categories. Familiarity information, starting at 140-160 ms, generalised across face categories and this generalisation was maintained in a very long time-window. In addition, temporal generalisation analysis showed that familiarity representations have an early, category-specific (90-140 ms) as well as a later, category-independent (>180 ms) processing stage. Our results extend previous human face familiarity evidence to another non-human face category and suggest that familiarity is a general, stimulus-invariant step during recognition memory processing.

The Phase Adjustment Task (PAT) has been described as one of the most promising new methods for assessing cardiac interoceptive accuracy. However, the suitability of this method for longitudinal research remains underexplored. In particular, it remains unclear whether performance on this measure changes with repeated testing in the absence of feedback. To explore potential practice/disengagement effects, we pooled data from all participants who had completed the PAT on two occasions within a ~7-day period (N = 73). Results revealed no evidence of practice/disengagement effects on the PAT. These findings indicate that one potential factor influencing the suitability of the PAT for longitudinal research - practice/disengagement effects - does not occur following repeated testing, providing further evidence of the appropriateness of this measure for longitudinal research.