Methodological differences in Pavlovian fear learning, extinction and return of fear

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Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Applied Psychology
Griffith Health
Examining methodological differences in fear conditioning and extinction studies is a growing area of research, inspired by the recent ‘replication crisis’ in psychological research. Determining whether methodological differences of fear conditioning and extinction paradigms contribute to inconsistent findings is important in terms of the translational value of this paradigm as an experimental analogue of exposure-based cognitive behavioural therapy. The aim of this thesis was to improve the experimental methodology of fear conditioning and extinction studies, by addressing three key questions: 1) Are there parameters of fear conditioning and extinction tasks that differentiate successful from unsuccessful extinction in studies with children and youth; 2) Do different types and combinations of within-phase subjective measures affect within-phase physiological and between-phase measures of fear conditioning and extinction; and 3) Does behavioural memory reconsolidation in the form of cue reactivation with versus without instructions differentially impact extinction and return of fear? Question one was addressed by conducting a systematic review of 35 fear conditioning and extinction studies conducted with children and adolescents (Chapter 2, Ryan et al., 2019). This review revealed that successful extinction was observed in studies that used fear irrelevant shapes (CS) and tones (US) (recommended for all youth) or fear relevant faces (CS) and screams (US) (recommended only for adolescents) as well as those studies that used 8 – 12 CS trials per acquisition and extinction phase. The most commonly used and effective dependent measures were skin conductance responses (SCRs) and subjective ratings of CS valence, fearfulness and arousal. Fear potentiated startle (FPS) was also effective, however less commonly used with children. It was suggested that standard measures be adopted for subjective ratings scales to assist in comparisons across studies. It was recommended that