Abstract
In recent years, loneliness and social isolation have become common social problems. Previous research has shown that loneliness affects the structure and function of the brain as well as function of the autonomic nervous system. Our previous study found that loneliness has a negative impact on the computation of relationship value in response to commitment signals from friends. In this study, we investigated whether heart rate variability (HRV), which is thought to reflect autonomic nervous function, is related to loneliness in young Japanese adults and whether experimental improvement of autonomic nervous activities alters the relationship value computation process in response to friends’ commitment signals. In Experiment 1, Japanese undergraduate students were assessed for loneliness and a resting electrocardiogram to determine HRV. In Experiment 2, other undergraduate students, separated into control and treatment groups, participated in a psychological task assessing responses to commitment signals from friends. The treatment group was subjected to autonomic nervous modulation prior to and while performing the task. Experiment 1 indicated a negative correlation between loneliness and percentage of the high frequency (HF) component in the total power of HRV, and a positive correlation between loneliness and the low-frequency (LF) component/HF ratio. Experiment 2 indicated that experimental improvement of HRV improved the subjective rating of the perceived commitment-confirming effect related to loneliness. These findings suggest that changes in cognitive functions caused by loneliness are not irreversible, and indicate that by improving autonomic nervous function, it is possible to improve cognitive functions that have changed due to loneliness.