Facial Expressions as a Social Signal: Are Angry Faces Fear-Relevant?

In order to increase chances of survival through evolution, humans may have retained a biological preparedness regarding associative learning with threatening stimuli. Prepared learning is indicated if learning is selective, occurs after only one training trial, is resistant to extinction and displays irrationality. Previous studies have shown that humans are prepared to learn associations between fear and threatening animal stimuli, such as snakes and spiders, indicating that snakes and spiders are 'fear-relevant stimuli'. The current study examined whether this would hold for threatening social stimuli, more specifically, angry faces, by using verbally instructed extinction to test whether fear conditioned to angry faces can be classed as irrational. A differential Pavlovian fear conditioning paradigm was used with angry male faces as the conditioned stimuli (CS), an aversive electrotactile stimulus as the unconditioned stimulus (US), which was paired with one of the angry faces (CS+), and electrodermal responses as the dependent variable. Before extinction, participants were split into two groups. One group was verbally instructed that there would be no more pairings between the CS+ and the US, while the other group was given no instruction. Verbal instruction eliminated differential conditioning in the instruction group, while differential conditioning continued to be shown in the no instruction group. This suggests that fear associated with angry faces does not persist irrationally and that angry faces are not fear-relevant stimuli