BODY RHYTHM AFFECTS BEHAVIOR, SMARTPHONE STUDY CONFIRMS

Tue 18 Apr 2023:

Human body’s rhythms may determine our behavior, according to a smartphone-based study.

Researchers from the Leiden University in the Netherlands analyzed the usage data of hundreds of mobile phones and discovered that the human body, both of men and women, has rhythms ranging between seven and 52 days. These cycles influence how we behave.

“If people think they just live their lives, deciding their behavior for themselves, and that there is no overarching structure, they’ve got it wrong,” said researcher Arko Ghosh, from the varsity.

The findings, described in an article in the journal npj Digital Medicine, showed that recurring patterns do not occur only in these kinds of psychological and neurological conditions, but that everyone has cycles lasting several days.

Spectral analysis of smartphone behavior based on inter-touch intervals. a We quantified smartphone behavior using the probability density of joint interval distribution (JID) in two-dimensional bins. An example of the probability density (PD) resulting from a series of 6 simulated interactions. b Example of behavioral activity of a subject captured by JID (left) accumulated over an hour-long window and (right) evolution of the probability density values at a select 2-dimensional bin over consecutive hourly windows (highlighted by using a small blue dot overlayed on the JID). c Periodogram for the two-dimensional bin selected above, obtained by averaging the continuous wavelet transform spectrogram over time, some of the peaks are marked using red arrows (red dashed line shows the 97.5^th percentile values based on block-bootstrap of the same data). d The power index (PI) of the selected periodogram peaks (red arrows in ‘c’) across the smartphone behavior. The two-dimensional bins that are not part of statistically significant clusters (multiple comparison correction, α = 0.05, ~1000 block bootstraps) are masked with a translucent layer. The unmasked PI values are shown in the smaller inserts. Credit: npj Digital Medicine (2023). DOI: 10.1038/s41746-023-00799-7

“These cycles influence our behavior. How they influence that behavior and what behavior relates to what particular times in the cycle is something we haven’t studied yet,” Ghosh said.

Together with his colleague Enea Ceolini, Ghosh included about 400 people, aged 16 to 80. An app was installed on their android phone that allowed the researchers to track and analyze usage data.

The team only looked at the times when people were actively using their phones and were swiping or typing.

“We made a striking discovery. We found that cycles of several days are very common: in old and young people, and in women and men. That last point is particularly remarkable,” Ghosh said.

“A lot of women face discrimination at work because their performance is often thought to suffer as a result of their menstrual cycle. Our research shows that women are not the only ones with a cycle. Men have a cycle, too, of 25 to 30 days, which also affects their behavior.”

The results may also have an impact on the research on psychological and neurological conditions.

Further, Ghosh stressed that two people may have the same cycle, but that they may respond completely differently to it. Further research can bring us more insights.

“We might then be able to predict particular behavior on the basis of a person’s cycle. This might in turn lead to a completely new definition of what is normal behavior and what is behavior that is related to a neurological or psychological condition,” Ghosh noted.