The role of expectancies and emotional load in false auditory perceptions among patients with schizophrenia spectrum disorders

Abstract

Cognitive models suggest that top-down and emotional processes increase false perceptions in schizophrenia spectrum disorders (SSD). However, little is still known about the interaction of these processes in false auditory perceptions. The present study aimed at investigating the specific as well as joint impacts of expectancies and emotional load on false auditory perceptions in SSD. Thirty-three patients with SSD and 33 matched healthy controls were assessed with a false perception task. Participants were asked to detect a target stimulus (a word) in a white noise background (the word was present in 60% of the cases and absent in 40%). Conditions varied in terms of the level of expectancy (1. no cue prior to the stimulus, 2. semantic priming, 3. semantic priming accompanied by a video of a man's mouth spelling out the word). The words used were neutral or emotionally negative. Symptom severity was assessed with the Positive and Negative Syndrome Scale. Higher expectancy significantly increased the likelihood of false auditory perceptions only among the patients with SSD (the group x expectancy condition interaction was significant), which was unrelated to general cognitive performance. Emotional load had no impact on false auditory perceptions in either group. Patients made more false auditory perceptions with high confidence than controls did. False auditory perceptions were significantly correlated with the severity of positive symptoms and disorganization, but not with other dimensions. Perception in SSD seems to be susceptible to top-down processes, increasing the likelihood of high-confidence false auditory perceptions.

Keywords: Confidence; False perception; Perceptual abnormalities; Psychosis.

Fig. 1

The design of a false perception task. False perception task consists of three main conditions: a–c, which varies on the degree and the type of the expectancy. In addition, all conditions consist of neutral and emotional words. Some of the words were audible (60%—auditory stimuli via headphones) and some of them were not audible (40%). All stimuli were presented with the street noise background. Participants had to response whether they hear or not a word. They were also asked whether they are sure or unsure in their response. False auditory perceptions were calculated as incorrect responses of heard word, when in fact no auditory stimuli were provided. In the condition A, the content of the target stimulus was not introduced by any clue. In the condition B, the content of the target stimulus was presented (the same word as the target stimulus) before the target stimulus was shown. In the final condition c, participants were presented with an integrated and congruent audio and visual stimulus of an actor spelling out the word

Fig. 2

Group differences in auditory false perceptions