Effects of Expectancy on Cognitive Performance, Mood, and Psychophysiology in Healthy Adolescents and Their Parents in an Experimental Study

Abstract

Objective: Placebo effects on cognitive performance and mood and their underlying mechanisms have rarely been investigated in adolescents. Therefore, the following hypotheses were investigated with an experimental paradigm: (1) placebo effects could be larger in adolescents than in adults, (2) parents' expectations influence their adolescents' expectations and placebo effects, and (3) a decrease in stress levels could be an underlying mechanism of placebo effects.Methods: Twenty-six healthy adolescents (13.8 ± 1.6 years, 14 girls) each with a parent (45.5 ± 4.2 years, 17 mothers) took part in an experimental within-subjects study. On two occasions, a transdermal patch was applied to their hips and they received an envelope containing either the information that it is a Ginkgo patch to improve cognitive performance and mood, or it is an inactive placebo patch, in counterbalanced order. Cognitive performance and mood were assessed with a parametric Go/No-Go task (PGNG), a modification of California Verbal Learning Test, and Profile of Mood Scales (POMS). Subjects rated their expectations about Ginkgo's effects before patch application as well as their subjective assessment of its effects after the tests. An electrocardiogram and skin conductance levels (SCLs) were recorded and root mean square of successive differences (RMSSD), high-frequency power (HF), and the area under the curve of the SCL (AUC) were analyzed as psychophysiological stress markers.Results: Expectations did not differ between adolescents and parents and were correlated concerning reaction times only. Overall, expectations did not influence placebo effects. There was only one significant placebo effect on the percentage of correct inhibited trials in one level of the PGNG in adolescents, but not in parents. RMSSD and HF significantly increased, and AUC decreased from pre-to post-patch application in adolescents, but not in parents.Conclusion: With this experimental paradigm, we could not induce relevant placebo effects in adolescents and parents. This could be due to aspects of the study design such as application form and substance, and that healthy subjects were employed. Nevertheless, we could show that adolescents are more sensitive to psychophysiological reactions related with interventions which could be part of the underlying mechanisms of placebo effects in adolescents.

Placebo induced expectations of mood enhancement generate a positivity effect in emotional processing

“…Importantly, we also observed a placebo-induced improvement of mood states in addition to the effects on face classification performance. Placebo effects on mood states in healthy individuals have been recently reported in some studies 44 – 46 while others were not able to demonstrate such effects 47 , 48 . Formal models such as the predictive coding framework 49 consider expectations as prior information, which, in a Bayesian sense, are integrated with incoming sensory information (likelihood), to form a percept (posterior) 3 , 50 .…”

Melodic Melodies: Is That All There is to Music?

“…Moreover, in both teens and young adults, it could be seen that more positive affects caused them to perform better in academics since they were more concentrated, had more attention, and could process things quicker than those who were feeling down (Science Daily, 2009). Likewise, improved memory, attention span, and a better working memory were all benefits that came to adults who experienced more positive emotions (Watolla et al, 2020;Raczy, Orzechowski, 2019). Older adults too had a better working memory when they experienced positive affect than when they experienced negative ones (Tieks et al, 2022).…”

“…Similar to other studies, it was found that adults that experienced more positive affect had a much quicker reaction time to questions asked and when speaking. Moreover, these adults were able to remember a lot more things and held their attention longer than adults who did not listen to music (Watolla et al, 2020). A study in 2019 found that mood along with emotional load, had a significant effect on cognitive performance, specifically memory.…”

“…Along with music, affect and mood played an important role in adults' cognitive performance. Similar to music, positive affect/mood was found to improve reaction time, attention span, and memory while a more negative affect/mood resulted in worse performance in these categories (Watolla et al, 2020;Raczy & Orzechowski, 2019). Since music is seen as both a mood and cognitive performance booster for adults, it would be beneficial to them to listen to music.…”

Risk perception and emotions: A psychophysiological study to understand why the numerical format matters.

“…We analyzed the skin conductance corrected time integral or AUC (Watolla et al, 2020). This area represents the change in skin conductance over a given time interval (15 s of the target).…”