Leiden University Student Repository

Čuljak, Matija 2022

Effect of daylight saving time measured as impulse response in smartphone behavior

Research master thesis | Psychology (research) (MSc)

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Daylight Saving Time (DST) is at its height of controversy in Europe and around the world, as many countries are considering abolishing it. However, little is known about how DST impacts...Show moreDaylight Saving Time (DST) is at its height of controversy in Europe and around the world, as many countries are considering abolishing it. However, little is known about how DST impacts individuals in naturalistic, cognitively-engaging tasks. By using smartphone touchscreen timestamp data from 336 participants in combination with a system identification and impulse response fitting approach, we measured changes in smartphone interactions for 15 days before and 15 days after spring and autumn DST transitions recorded from 2018 to 2021. Our aim was to explore the effect of DST smartphone interactions, including how long DST transitions impact individuals, whether individuals show similarities in their DST responses, and whether age and gender explain differences in DST responses. We found that most individuals were impacted by DST transitions, with a median recovery period of 26 days, almost twice as long as prior estimates. Additionally, hierarchical clustering revealed that some individuals show similarities in their responses to DST, in addition to large inter-individual differences. We also found that differences in the DST response are not explained by age or gender. We propose that large inter-individual differences in responses to DST might be explained by the ability for individuals to self-select their sleep-wake patterns independently of day-night cycles. Additionally, these large inter-individual differences could partly explain the controversy behind DST, as further investigation needs to be made into what causes individuals to respond differently to DST.Show less