Observational learning of fear in real time procedure

Learning to avoid threats often occurs by observing others. Most previous research on observational fear learning (OFL) in humans has used pre-recorded standardized video of an actor and thus lacked ecological validity. Here, we aimed to enhance ecological validity of the OFL by engaging participants in a real-time observational procedure (35 pairs of healthy male friends, age 18–27). One of the participants watched the other undergo a differential fear conditioning task, in which a conditioned stimulus (CS+) was paired with an aversive electric shock and another stimulus (CS−) was always safe. Subsequently, the CS+ and CS− were presented to the observer to test the OFL. While the friend’s reactions to the shock elicited strong skin conductance responses (SCR) in all observers, subsequent differential SCRs (CS+ > CS−) were found only when declarative knowledge of the CS+/US contingency (rated by the participants) was acquired. Contingency-aware observers also showed elevated fear potentiated startle responses during both CS+ and CS− compared to baseline. We conclude that our real-time procedure can be effectively used to study OFL. The procedure allowed for dissecting two components of the OFL: an automatic emotional reaction to the response of the demonstrator and learning about stimulus contingency.

Human fear conditioning depends on stimulus contingency instructions

Human fear conditioning is often seen as the result of a highly automatic process that is independent of higher cognitive functions and verbal instructions. However, cumulative research findings call this view into question. In the current preregistered study (N = 102), we investigated whether the number of participants who successfully show conditioned fear acquisition depends on the instructions given to them before the fear conditioning phase. Particularly, one third of the participants were instructed about the precise contingency between the conditioned stimulus (CS) and unconditioned stimulus (US). Another third was merely instructed that there would be a contingency. The last third did not get any instructions about the CS-US contingency. We found facilitated fear acquisition rate in the first and second group compared to the third group. Furthermore, contingency reversal instructions following the acquisition phase reversed both conditioned skin conductance and startle responses. These results highlight that researchers should systematically report the instructions given to participants in human fear conditioning studies.

Observed but Never Experienced – Vicarious Learning of Fear Under Ecological Conditions

Learning to avoid threats often occurs by observing the behavior of others. Most previous research on observational fear learning in humans has used pre-recorded stimuli as social cues. Here, we aimed to enhance the ecological validity of the learning situation: the ‘observer’ watched their friend (‘demonstrator’) performing a differential fear-conditioning task in real time. During the task, one conditioned stimulus (CS+) was repeatedly linked with electric stimulation (US) while another one (CS-) was always safe. Subsequently, the observer was presented with the CS+ and CS- directly but without receiving any shocks. Skin conductance (SCR) and fear-potentiated startle (FPS) responses were measured in observers throughout the whole experiment. While the US applied to the demonstrator elicited strong SCR in the observers, subsequent differential SCR to CSs (CS+ vs. CS-) presented directly were dependent on declarative knowledge of the CS+/US contingency. Contingency-aware observers also showed elevated FPS during both CS+ and CS- compared to intertrial intervals. We conclude that observational fear learning involves two components: an automatic emotional reaction to the response of the demonstrator and learning to predict stimulus contingency (CS+/US pairing). Ecological modifications proposed offer new perspectives on studying social learning of emotions.