Don‘t fear fear conditioning – Methodological considerations for design and analysis of human fear acquisition, extinction and return of fear studies:
The so-called ‘replicability crisis’ in psychology has sparked methodological discussions in many areas of science in general and psychology in particular. This has led to recent endeavors of the scientific community to promote the transparency, rigor and ultimately replicability of research.
Originating from this zeitgeist, the challenge to discuss critical issues on terminology, design, methods, and analysis considerations in fear conditioning research has recently been taken up by the ‘Research Network for the European Interdisciplinary Study of Fear and Extinction Learning as well as the Return of Fear (EIFEL-ROF)’.
A group of (young) scientists have met on a regular base since May 2015 to identify and debate on urgent open questions and important methodological considerations. This endeavor originated from and is reflective of the spirit of the annual European Meeting on Human Fear Conditioning (EMHFC).
The outcome of these fruitful discussions, a comprehensive review-type article (Lonsdorf et al., Neuroscience and Biobehavioral Reviews, 2017), is intended to provide a basis for the development of a common procedural framework for the field of human fear conditioning and provide encyclopedic guidance for methodological decisions on design and analysis is under review. Thereby, we hope to spark fruitful discussions and methodological research projects to ultimately establish a consensus in the field with respect to design and analysis considerations.
In addition, we have initated a number of studies on the impact of apparently subtle changes in design/methods such as the inclusion of fear ratings or the presentation of startle probes, on the process under study (Sjouwerman et al., Psychophysiology, 2016). Additional investigations for instance on the impact of different indices to quantify extinction and extinction recall, different response quantification procedures for SCRs/FPS are ongoing.
Individual differences fear conditioning, extinction and return of fear in humans: temperamental, experiential and biological factors:
Why do some individuals develop pathological anxiety in the aftermath of trauma while others do not? Clearly, exposure to a traumatic event is not sufficient for the development of fear- and stress- related disorders. Individuals do not only differ with respect to exposure to life adversity before, during and after trauma (experiential differences) but also differ in personality (i.e. trait variables) and/or biological factors, all of which strongly impact vulnerability to pathological anxiety or its opposite pole resilience. Thereby, experimental studies on individual differences may provide critical insights into the mechanisms underlying divergent responses in the aftermath of traumatic experiences and individual differences in the development of anxiety disorders. Ultimately, this may help to pinpoint factors that predispose to psychopathology or resilience and ultimately inform the development of novel prevention and intervention programs and therapeutic targets.
Members of the network have published a systematic review article on individual difference factors in fear conditioning research including methodological considerations (Lonsdorf & Merz, Neuroscience and Biobehavioral Reviews, 2017).
Translational challenges in fear conditioning research:
Project 1 (methodological challenges in human fear conditioning research) has sparked disucssions on translational challenges in the field and comparability of methods and procedures employed in rodents and humans. Currently, we are working on a publiscaion on translational challenges in the field that originates from discussions during our workshop in May 2017 with experts from the field of rodent research on fear conditioning (Dr. Stephen Maren, Texas, Dr. Carsten Wotjak, MPI Munich and Dr. Kai Jüngling, Münster).
Development of evidence-based methodological recommendations:
Some recomendations in the field of fear conditioning reserach have been developed in the 1970ies and not yet been re-considered with new technological developments allowing us to capture psychophysiological responses wither a higher resolution. Hence a number of subprojects have been initiated across labs to develop evidence-based methdological recommendations:
Sub-project 1: Onset-latencies in skin conductance responses across stimlus types in fear conditioning (US, CS+, CS-).
Sub-project 2: Different operationalizations of “extinction” and extinction recall indices” and their impact on results.
Sub-project 3: Comparison of different ways (fully automatized vs. manual) to quantify fear potentiated startle responses.
Sub-project 4: Frequency of zero-reponses in skin conductance responses and fear potentiated startle responses across stimuli and across data sets in fear conditioning research. Defitition of zero-reponder across publications in the field.
Cross-laboratory replication attemps in fear conditioning reserach.