Fear conditioning and stimulus generalization in association with age in children and adolescents

Abstract

The aim of the study was to investigate age-related differences in fear learning and generalization in healthy children and adolescents (n = 133), aged 8–17 years, using an aversive discriminative fear conditioning and generalization paradigm adapted from Lau et al. (2008). In the current task, participants underwent 24 trials of discriminative conditioning of two female faces with neutral facial expressions, with (CS+) or without (CS−) a 95-dB loud female scream, presented simultaneously with a fearful facial expression (US). The discriminative conditioning was followed by 72 generalization trials (12 CS+, 12 GS1, 12 GS2, 12 GS3, 12 GS4, and 12 CS−): four generalization stimuli depicting gradual morphs from CS+ to CS− in 20%-steps were created for the generalization phases. We hypothesized that generalization in children and adolescents is negatively correlated with age. The subjective ratings of valence, arousal, and US expectancy (the probability of an aversive noise following each stimulus), as well as skin conductance responses (SCRs) were measured. Repeated-measures ANOVAs on ratings and SCR amplitudes were calculated with the within-subject factors stimulus type (CS+, CS−, GS1-4) and phase (Pre-Acquisition, Acquisition 1, Acquisition 2, Generalization 1, Generalization 2). To analyze the modulatory role of age, we additionally calculated ANCOVAs considering age as covariate. Results indicated that (1) subjective and physiological responses were generally lower with increasing age irrespective to the stimulus quality, and (2) stimulus discrimination improved with increasing age paralleled by reduced overgeneralization in older individuals. Longitudinal follow-up studies are required to analyze fear generalization with regard to brain maturational aspects and clarify whether overgeneralization of conditioned fear promotes the development of anxiety disorders or vice versa.

Developmental aspects of fear generalization – A MEG study on neurocognitive correlates in adolescents versus adults

“…This is in line with evidence in healthy populations showing steeper, i.e. more discriminative, generalization gradients in older compared to younger individuals ( Glenn et al, 2012 , Klein et al, 2021 , Reinhard et al, 2021 , Schiele et al, 2016 ). Discrimination performance, as assessed by the PM-Task, improved after compared to before conditioning (see also Roesmannet al, 2022a ), yet, we found no evidence for age-related group differences.…”

“…In most outcome measures, – with the exception of UCS expectancy ratings – adolescents showed generalization gradients similar to those observed in adults. This points towards a rather advanced developmental stage in adolescents, in line with findings of a more adult-like generalization pattern in older versus younger children ( Glenn et al, 2012 ) and steeper generalization gradients in healthy adolescents compared to children ( El-Bar et al, 2017 , Reinhard et al, 2021 ). In addition to the interpretation that adolescents achieved a level of development that is comparable with adults (in many respects), the lack of group differences in fear ratings might also be grounded in the overall rather low fear ratings - even in response to the CS+ .…”

“…Generalization gradients were shown to become steeper (i.e. more discriminative) with increasing age ( Glenn et al, 2012 , Reinhard et al, 2021 , Schiele et al, 2016 ). Glenn and colleagues ( Glenn et al, 2012 ) reported that FPS and fear ratings in older children (11–13 years) showed the typical fear generalization pattern (CS- < GS < CS+) as observed in adults.…”

“…Evidence for shallower generalization gradients in healthy children was further substantiated by Schiele and colleagues ( Schiele et al, 2016 ), who reported higher arousal ratings and SCRs to the GS in children (8–10 years) versus adults (18–50 years). Additionally, Reinhard and colleagues ( Reinhard et al, 2021 ) reported correlational evidence for improved CS+ /CS- discrimination and reduced overgeneralization in UCS expectancy ratings with increasing age in a sample of children and adolescents (8–17 years). In sum, these findings suggest that conditioned fear responses are less specific (shallower generalization gradients) in childhood and might develop to become increasingly specific (steeper or quadratic generalization gradients) throughout adolescence.…”

Association between fears and behavior/ emotional problems in toddlers and preschoolers

“…However, the age pattern reported by other researchers, with younger children displaying more fears than older children (KUSHNIR;SADEH, 2009;MCLENON;ROGERS, 2018;REIN-HARD et al, 2021) was not found in our sample. This is likely because our study compared toddlers with preschoolers, while the other studies (KUSHNIR; SA-DEH, 2009;REINHARD et al, 2021) used school children (between six and 11 years old) samples and subdivided them for the comparisons. To endorse that hypothesis, we can argue that fears still unfold in this toddler and preschool age group (KONKABAYEVA et al, 2016;WARREN;OLLENDICK;SIMMENS, 2008).…”