A number of studies have suggested various effects that the circadian rhythm has on our lives, from mood  to our immune system. It is also likely to impact our day-to-day lives, as such a team at the University of Bristol looked into how it could affect our thoughts and emotions. The authors analysed a sample of over 800m Tweets from UK users posted throughout the day over a four-year period by comparing the words used to linguistic lists that had been designed to infer various psychological states of a person. They found that two independent peak times were able to explain 85% of the variance in word usage seen. The first is a peak at 5-6am that is correlated with analytical thinking, motivational thinking, and personal concerns, and is negatively correlated with negative language and social concerns. The second is a peak at 3-4am, correlated with existential concerns, and negatively correlated with positive emotions. These time peaks are also associated with major changes in neural activity and hormonal levels.
The language we use changes drastically throughout the day, a reflection of changes in our main concerns, and cognitive and emotional processes.
— Peter Chilton, Research Fellow
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- Lange T, Dimitrov S, Born J. Effects of sleep and circadian rhythm on the human immune system. Ann N Y Acad Sci. 2010; 1193:48-59.
- Dzogang F, Lightman S, Cristianini N. Diurnal variations of psychometric indicators in Twitter content. PLOS One. 2018.