Optimising Extinction of Conditioned Disgust

Abstract

Maladaptive disgust responses are tenacious and resistant to exposure-based interventions. In a similar vein, laboratory studies have shown that conditioned disgust is relatively insensitive to Conditioned Stimulus (CS)-only extinction procedures. The relatively strong resistance to extinction might be explained by disgust's adaptive function to motivate avoidance from contamination threats (pathogens) that cannot be readily detected and are invisible to the naked eye. Therefore, the mere visual presentation of unreinforced disgust eliciting stimuli might not be sufficient to correct a previously acquired threat value of the CS+. Following this, the current study tested whether the efficacy of CS-only exposure can be improved by providing additional safety information about the CS+. For the CSs we included two neutral items a pea soup and a sausage roll, whereas for the Unconditioned Stimulus (US) we used one video clip of a woman vomiting and a neutral one about glass blowing. The additional safety information was conveyed by allowing actual contact with the CS+ or by observing an actress eating the food items representing the CS+. When additional safety information was provided via allowing direct contact with the CS+, there was a relatively strong post-extinction increase in participants' willingness-to-eat the CS+. This beneficial effect was still evident at one-week follow up. Also self-reported disgust was lower at one-week follow up when additional safety information was provided. The current findings help explain why disgust is relatively insensitive to CS-only extinction procedures, and provide helpful starting points to improve interventions that are aimed to reduce distress in disgust-related psychopathology.

Fig 1. Self-reported disgust.

Total scores in the different phases (habituation, acquisition, extinction, 24hrs and 7 days) of the self-reported disgust.

Fig 2. Self-reported willingness-to-eat.

Total scores in the different phases (habituation, acquisition, extinction, 24hrs and 7 days) of the self-reported willingness-to-eat.

Fig 3. Self-reported valence.

Total scores in the different phases (habituation, acquisition, extinction, 24hrs and 7 days) of the self-reported valence.

Fig 4. Corrugator conditioned response.

Mean response in the different phases (habituation, acquisition, extinction) of the facial corrugator towards the CS+ and CS−.

Fig 5. Levator conditioned response.

Mean response in the different phases (habituation, acquisition, extinction) of the facial levator towards the CS+ and CS−.