Reciprocal relationships between positive expectancies and positive emotions during the COVID-19 pandemic: a cross-lagged panel study

INTRODUCTION

Previous research highlighted the importance of investigating distinct protective factors that predict the experience of positive emotions during stressful situations, such as the COVID-19 pandemic. In this longitudinal study, we specifically focused on positive expectancies towards the future (optimism, response expectancy, and response hope) in relation to the experience of positive emotions during the COVID-19 pandemic. Our primary objectives were to identify the best predictors for experiencing short-term and long-term positive emotions and investigate their interrelationships.

METHODS

Data from 271 participants (average age = 29.2 years, 84.7% female) were analyzed using four cross-lagged models.

RESULTS

Results showed that response expectancy was the best predictor for experiencing positive emotions in the short term, while optimism was the best predictor for experiencing positive emotions in the long term. Additionally, through further exploratory analysis, multiple bidirectional relationships were identified between positive expectancies and positive emotions.

DISCUSSION

Our results highlight the significant role played by positive expectancies in predicting the experience of positive emotions. Specifically, dispositional optimism emerged as a stronger predictor of longer-term positive emotions, whereas response expectancy proved to be a better predictor of shorter-term positive emotions. Thus, interventions targeting positive expectancies have the potential to enhance emotional functioning in individuals during challenging situations like the COVID-19 pandemic.

Classical Conditioning as a Distinct Mechanism of Placebo Effects

Classical conditioning was suggested as a mechanism of placebo effects in the 1950s. It was then challenged by response expectancy theory, which proposed that classical conditioning is just one of the means by which expectancies are acquired and changed. According to that account, placebo effects induced by classical conditioning are mediated by expectancies. However, in most of the previous studies, either expectancies were not measured or classical conditioning was combined with verbal suggestions. Thus, on the basis of those studies, it is not possible to conclude whether expectancies are involved in placebo effects induced by pure classical conditioning. Two lines of recent studies have challenged the idea that placebo effects induced by classical conditioning are always mediated by expectancies. First, some recent studies have shown that a hidden conditioning procedure elicits both placebo analgesia and nocebo hyperalgesia, neither of which is predicted by expectancy. Second, there are studies showing that visual cues paired with pain stimuli of high or low intensity induce both placebo analgesia and nocebo hyperalgesia when they are presented subliminally without participants' awareness. The results of both lines of studies suggest that expectancy may not always be involved in placebo effects induced by classical conditioning and that conditioning may be a distinct mechanism of placebo effects. Thus, these results support the idea that placebo effects can be learned by classical conditioning either consciously or unconsciously. However, the existing body of evidence is limited to classically conditioned placebo effects in pain, that is, placebo analgesia and nocebo hyperalgesia.

Effect of a nausea expectancy manipulation on chemotherapy-induced nausea: a university of Rochester cancer center community clinical oncology program study

Several studies have shown that patients' expectancies for the development of nausea following chemotherapy are robust predictors of that treatment-related side effect, and some studies have shown that interventions designed to influence expectancies can affect patients' reports of symptoms. In this randomized, multicenter, Community Clinical Oncology Program trial, we investigated the effect of an expectancy manipulation designed to reduce nausea expectancy on chemotherapy-induced nausea in 358 patients scheduled to receive chemotherapy treatment. Patients in the intervention arm received general cancer-related educational material plus specific information about the efficacy of ondansetron, specifically designed to diminish nausea expectancy. Patients in the control arm received only the general cancer-related educational material. Nausea expectancy was assessed both prior to and following the educational intervention. We observed a significant reduction in nausea expectancy in the intervention group (P=0.024) as compared to the control group (P=0.34). In the intervention group, patients' expectations of nausea assessed prior to the intervention correlated significantly with average nausea (r=0.27, P=0.001), whereas nausea expectancy assessed following the intervention did not (r=0.1, P=0.22). Although the expectancy manipulation reduced patients' reported expectations for the development of nausea, the occurrence of nausea was not reduced. Furthermore, post-intervention nausea expectancy compared to pre-intervention expectancy was less predictive of subsequent nausea. Explanations for these findings include the possibility that the expectancy manipulation was not strong enough, and the possibility that changing nausea expectancies does not change occurrence of nausea.