Toward a reliable detection of arachnophobia: subjective, behavioral, and neurophysiological measures of fear response

Abstract

IntroductionThe administration of questionnaires presents an easy way of obtaining important knowledge about phobic patients. However, it is not well known how these subjective measurements correspond to the patient’s objective condition. Our study aimed to compare scores on questionnaires and image evaluation to the objective measurements of the behavioral approach test (BAT) and the neurophysiological effect of spiders extracted from fMRI measurements. The objective was to explore how reliably subjective statements about spiders and physiological and behavioral parameters discriminate between phobics and non-phobics, and what are the best predictors of overall brain activation.MethodsBased on a clinical interview, 165 subjects were assigned to either a “phobic” or low-fear “control” group. Finally, 30 arachnophobic and 32 healthy control subjects (with low fear of spiders) participated in this study. They completed several questionnaires (SPQ, SNAQ, DS-R) and underwent a behavioral approach test (BAT) with a live tarantula. Then, they were measured in fMRI while watching blocks of pictures including spiders and snakes. Finally, the respondents rated all the visual stimuli according to perceived fear. We proposed the Spider Fear Index (SFI) as a value characterizing the level of spider fear, computed based on the fMRI measurements. We then treated this variable as the “neurophysiological effect of spiders” and examined its contribution to the respondents’ fear ratings of the stimuli seen during the fMRI using the redundancy analysis (RDA).ResultsThe results for fear ranks revealed that the SFI, SNAQ, DS-R, and SPQ scores had a significant effect, while BAT and SPQ scores loaded in the same direction of the first multivariate axis. The SFI was strongly correlated with both SPQ and BAT scores in the pooled sample of arachnophobic and healthy control subjects.DiscussionBoth SPQ and BAT scores have a high informative value about the subject’s fear of spiders and together with subjective emotional evaluation of picture stimuli can be reliable predictors of spider phobia. These parameters provide easy and non-expensive but reliable measurement wherever more expensive devices such as magnetic resonance are not available. However, SFI still reflects individual variability within the phobic group, identifying individuals with higher brain activation, which may relate to more severe phobic reactions or other sources of fMRI signal variability.

Are vipers prototypic fear-evoking snakes? A cross-cultural comparison of Somalis and Czechs

“…In previous research, we established a correspondence between the evaluation of the level of subjectively perceived fear elicited by pictures of snakes or spiders, psychophysiological reactions (such as skin resistance and heart rate), and the intensity of brain activity that we measured in fMRI. The majority of these parameters related to the level of subjectively perceived fear, elicited by snake or spider photographs, also closely aligned with the behavioral parameters measured in the behavioral approach test (Landová et al, 2020(Landová et al, , 2023. Furthermore, in non-human primates, realistic photographs (in size and color) placed in the natural context, stimulate anti-predator behavior in capuchin monkeys (Meno et al, 2013a,b).…”

“…As the evaluation of the threat that animals may represent encompasses implicit automatic reactions, as well as long-term goal-directed cognitive and emotional evaluations labeled as explicit processes ( Effting et al, 2016 ), we can assume that both processes collaborate in the subjective evaluation of fear elicited by particular animal species. This level of subjectively perceived fear may be related to overall decision-making about the potential level of threat, and it is also connected with the subsequent behavioral reaction (see Landová et al, 2023 , for how the subjective fear evaluation of pictures and individual fearfulness are related to overall brain activity). This raises the question of whether modern humans can distinguish venomous snakes from non-venomous snakes based on the degree of subjectively perceived fear and how this degree of subjectively perceived fear is affected by the risk that venomous snakes pose today and in the evolutionary past ( Bertels et al, 2023 ).…”

Animals evoking fear in the Cradle of Humankind: snakes, scorpions, and large carnivores

“…Nonetheless, these two are not completely independent. There is some evidence that self-reported fear of animals correlates with physiological response such as skin resistance (snakes: r = 0.77, Landová et al 2020 ) or fMRI activation (Landová et al 2023 ). Specifically in Somaliland, supportive evidence comes from eye-tracking studies focusing on scorpions (Rudolfová et al 2022 ) and snakes (Štolhoferová et al submitted).…”

Attentional, emotional, and behavioral response toward spiders, scorpions, crabs, and snakes provides no evidence for generalized fear between spiders and scorpions

“…In the following eye-tracking study, we measured an attentional, behavioral, and emotional aspect of the reaction to snakes, spiders, crabs, and scorpions used as distractors to uncover a pattern of generalization among these stimuli. Physiological and psychological responses are often interlinked, and some physiological parameters are considered a good proxy for psychological processes 39 . For example, electrodermal activity can reflect subjective emotional arousal or significance of the animal stimuli 40 , 41 , especially snakes 24 , and is thus a useful method in both basic and applied research 24 , 42 .…”