Browsing by Author "van Honk, Jack"

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    In the eye of the beholder: Reduced threat-bias and increased gaze-imitation towards reward in relation to trait anger
    (Public Library of Science, 2012) Terburg, David; Aarts, Henk; Putman, Peter; van Honk, Jack
    The gaze of a fearful face silently signals a potential threat's location, while the happy-gaze communicates the location of impending reward. Imitating such gaze-shifts is an automatic form of social interaction that promotes survival of individual and group. Evidence from gaze-cueing studies suggests that covert allocation of attention to another individual's gaze-direction is facilitated when threat is communicated and further enhanced by trait anxiety. We used novel eye-tracking techniques to assess whether dynamic fearful and happy facial expressions actually facilitate automatic gaze-imitation. We show that this actual gaze-imitation effect is stronger when threat is signaled, but not further enhanced by trait anxiety. Instead, trait anger predicts facilitated gaze-imitation to reward, and to reward compared to threat. These results agree with an increasing body of evidence on trait anger sensitivity to reward.
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    Paradoxical facilitation of working memory after basolateral amygdala damage
    (Public Library of Science, 2012) Morgan, Barak; Terburg, David; Thornton, Helena B; Stein, Dan J; van Honk, Jack
    Working memory is a vital cognitive capacity without which meaningful thinking and logical reasoning would be impossible. Working memory is integrally dependent upon prefrontal cortex and it has been suggested that voluntary control of working memory, enabling sustained emotion inhibition, was the crucial step in the evolution of modern humans. Consistent with this, recent fMRI studies suggest that working memory performance depends upon the capacity of prefrontal cortex to suppress bottom-up amygdala signals during emotional arousal. However fMRI is not well-suited to definitively resolve questions of causality. Moreover, the amygdala is neither structurally or functionally homogenous and fMRI studies do not resolve which amygdala sub-regions interfere with working memory. Lesion studies on the other hand can contribute unique causal evidence on aspects of brain-behaviour phenomena fMRI cannot "see". To address these questions we investigated working memory performance in three adult female subjects with bilateral basolateral amygdala calcification consequent to Urbach-Wiethe Disease and ten healthy controls. Amygdala lesion extent and functionality was determined by structural and functional MRI methods. Working memory performance was assessed using the Wechsler Adult Intelligence Scale-III digit span forward task. State and trait anxiety measures to control for possible emotional differences between patient and control groups were administered. Structural MRI showed bilateral selective basolateral amygdala damage in the three Urbach-Wiethe Disease subjects and fMRI confirmed intact functionality in the remaining amygdala sub-regions. The three Urbach-Wiethe Disease subjects showed significant working memory facilitation relative to controls. Control measures showed no group anxiety differences. Results are provisionally interpreted in terms of a 'cooperation through competition' networks model that may account for the observed paradoxical functional facilitation effect.
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    Testosterone administration increases the size of womens' peripersonal space: An embodied index of social dominance
    (2019) Masson, Catherine Jane; Solms, Mark; van Honk, Jack
    Peripersonal space (PPS) is the space immediately surrounding the body, encoded by a specific frontoparietal network of multimodal neurons. Stimuli in PPS are represented in a body-part centred manner in terms of possibilities for action, and PPS representations function to facilitate defensive and/or approaching responses to stimuli. The size of PPS differs between individuals and contexts, with physical and psychological factors having a determining role on the size of PPS. For these reasons, PPS has been conceptualised as ‘the space of the bodily self'. In this study we investigated whether the dominance enhancing effects of testosterone may reflect in changes of the representation of PPS. We conducted a double-blind placebo-controlled within-subjects testosterone administration study in women (N=19) where participants performed a multisensory-integration task (a commonly used measure of PPS) while facing an unknown confederate. Results indicated that in comparison to placebo, the administration of testosterone caused a significant enlargement of participants' PPS, suggesting that testosterone caused participants to reflexively appropriate a larger space as their own. This effect was particularly pronounced in participants with higher trait anxiety, converging with other research which has shown that the dominance enhancing effects of testosterone administration can be particularly effective in anxious individuals. Results also indicated a multisensory-facilitation effect around the confederate, which was constant across testosterone and placebo conditions – confirming that the effect of testosterone was self-specific. The PPS boundary gradient was unchanged by testosterone. These findings suggest that an enlarged PPS may provide an embodied index of social dominance. Further, because PPS representations function to support approaching and/or defensive responses to the environment, an enlarged PPS due to raised testosterone may support the enhanced approach behaviour and vigilance to threat known to be conferred by testosterone.