Anthony J. Nelson

Amygdala responses to averted vs direct gaze fear vary as a function of presentation speed

We examined whether amygdala responses to rapidly presented fear expressions are preferentially tuned to averted vs direct gaze fear and conversely whether responses to more sustained presentations are preferentially tuned to direct vs averted gaze fear. We conducted three functional magnetic resonance imaging (fMRI) studies to test these predictions including: Study 1: a block design employing sustained presentations (1 s) of averted vs direct gaze fear expressions taken from the Pictures of Facial Affect; Study 2: a block design employing rapid presentations (300 ms) of these same stimuli and Study 3: a direct replication of these studies in the context of a single experiment using stimuli selected from the NimStim Emotional Face Stimuli. Together, these studies provide evidence consistent with an early, reflexive amygdala response tuned to clear threat and a later reflective response tuned to ambiguous threat.

Emotion in the neutral face: A mechanism for impression formation?

The current work examined contributions of emotion-resembling facial cues to impression formation. There exist common facial cues that make people look emotional, male or female, and from which we derive personality inferences. We first conducted a Pilot Study to assess these effects. We found that neutral female versus neutral male faces were rated as more submissive, affiliative, naïve, honest, cooperative, babyish, fearful, happy, and less angry than neutral male faces. In our Primary Study, we then “warped” these same neutral faces over their corresponding anger and fear displays so the resultant facial appearance cues now structurally resembled emotion while retaining a neutral visage (e.g., no wrinkles, furrows, creases, etc.). The gender effects found in the Pilot Study were replicated in the Primary Study, suggesting clear stereotype-driven impressions. Critically, ratings of the neutral-over-fear warps versus neutral-over-anger warps also revealed a profile similar to the gender-based ratings, revealing perceptually driven impressions directly attributable to emotion overgeneralisation.

Differentially tuned responses to restricted versus prolonged awareness of threat: a preliminary fMRI investigation.

Responses to threat occur via two known independent processing routes. We propose that early, reflexive processing is predominantly tuned to the detection of congruent combinations of facial cues that signal threat, whereas later, reflective processing is predominantly tuned to incongruent combinations of threat. To test this prediction, we examined responses to threat-gaze expression pairs (anger versus fear expression by direct versus averted gaze). We report on two functional magnetic resonance imaging (fMRI) studies, one employing prolonged presentations (2s) of threat-gaze pairs to allow for reflective processing (Study 1), and one employing severely restricted (33 ms), backward masked presentations of threat-gaze pairs to isolate reflexive neural responding (Study 2). Our findings offer initial support for the conclusion that early, reflexive responses to threat are predominantly tuned to congruent threat-gaze pairings, whereas later reflective responses are predominantly tuned to ambiguous threat-gaze pairings. These findings highlight a distinct dual function in threat perception.