Do CS-US Pairings Actually Matter? A Within-Subject Comparison of Instructed Fear Conditioning with and without Actual CS-US Pairings

Abstract

Previous research showed that instructions about CS-US pairings can lead to fear of the CS even when the pairings are never presented. In the present study, we examined whether the experience of CS-US pairings adds to the effect of instructions by comparing instructed conditioning with and without actual CS-US pairings in a within-subject design. Thirty-two participants saw three fractals as CSs (CS+1, CS+2, CS−) and received electric shocks as USs. Before the start of a so-called training phase, participants were instructed that both CS+1 and CS+2 would be followed by the US, but only CS+1 was actually paired with the US. The absence of the US after CS+2 was explained in such a way that participants would not doubt the instructions about the CS+2-US relation. After the training phase, a test phase was carried out. In this phase, participants expected the US after both CS+s but none of the CS+s was actually paired with the US. During test, self-reported fear was initially higher for CS+1 than for CS+2, which indicates that the experience of actual CS-US pairings adds to instructions about these pairings. On the other hand, the CS+s elicited similar skin conductance responses and US expectancies. Theoretical and clinical implications are discussed.

Can prepared fear conditioning result from verbal instructions?

“…To test for this hypothesis, we adopted a procedure developed by Raes, De Houwer, De Schryver, Brass, and Kalisch (2014) which allowed a within-subject comparison of instructed fear conditioning with and without actual CS-US pairings. In this procedure, participants are instructed about two CSs that are said to be predictive of an electrical stimulus.…”

“…This is supported by a number of studies that show that verbal instructions can result in the acquisition of defensive responses (Cameron et al, 2016;Costa, Bradley, & Lang, 2015;Grillon, Ameli, Woods, Merikangas, & Davis, 1991) and subjective feelings of fear and distress (Raes, De Houwer, De Schryver, Brass, & Kalisch, 2014;Soeter & Kindt, 2012), which are considered to be affective measures of fear (Hamm & Weike, 2005;Soeter & Kindt, 2012). Such results call into question whether distinctions should be made between the processes underlying learning via verbal instructions and other types of learning.…”

“…Additionally, SCRs were averaged per two trials to obtain an equal number of data points as for the subjective ratings (as in Raes et al, 2014).…”

“…US expectancy and fear ratings were collected in separate blocks, interspersed throughout the experiment (as in Raes et al, 2014). Right before this block, participants were asked to think back to their most recent encounter with the stimulus and were told that questions regarding the expectancy of the electrical stimulus referred only to the actual electrical stimulus and not the picture of the lightning bolt (which was used as a placeholder for CS+2 during a practice phase; see below).…”

“…This was accomplished by adopting a procedure introduced by Raes, De Houwer, De Schryver, Brass and Kalisch (2014) that allowed us to manipulate on a within-subjects basis whether verbally threatened CSs are actually paired with the US. On the basis of the fear learning module account of Öhman and Mineka (2001), we expected that actually experiencing the instructed contingencies would strengthen prepared learning effects because effects of actual CS-US pairings are assumed to be mediated in part by the fear learning module (Olsson & Phelps, 2004.…”