Kristoffer Lind Glavind forsvarer sin ph.d.-afhandling

Kristoffer Lind Glavind forsvarer sin ph.d.-afhandling:"Smartphones’ effects on attention and behavior"


Kristoffer Lind Glavind

Titel: "Smartphones’ effects on attention and behavior"

Tid og sted: 2. november 2021 kl. 14:15 i lokale CSS 1.1.18.

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En elektronisk kopi af afhandlingen kan fås ved henvendelse til:


  • Mogens Fosgerau, Økonomisk Institut, Københavns Universitet, Danmark (formand)
  • Associate Professor Michael Szell, ITU
  • Professor dr. JN van Ommeren, Vrije Universiteit Amsterdam


In this Ph.D. dissertation, I analyze how smartphones affect human life through three separate chapters. Examining different domains of human life, the chapters have several things in common. First, they all relate to how smartphones affect human attention. Second, they all use data collected from smartphones to examine the influence of smartphones. Third, in all three chapters, analyzes are made based on advanced data structuring and the use of econometric models seeking to establish causal claims when possible.

Smartphone use is socially contagious
In the first chapter, we show a sharp increase in smartphone use when traveling between EU countries after June 15th, 2017, when the Roam-Like-at-Home initiative removed tariffs. We see this as causal evidence that the Roam-Like-at-Home initiative increased smartphone use, with an average daily increase in screentime of 6%. This increase was primarily driven by social media apps, browser and search apps, and map apps. Further, we investigate the effect on mobility patterns and find that while travelers due to free roaming visit 6% more locations a day, they spend 5% less time on transportation like cars and trains. This suggests that mobile internet access help travelers visit more places and travel more efficiently.

Nature unplugged or interrupted?
In the second chapter, we contribute to an extensive literature on how natural areas affect human well-being. We examine both the effect of natural areas overall (both recreational and nature areas) and recreational and nature areas separately.

We use data from the Copenhagen Network Study to follow 701 young adults' phone use for two years and fixed effects models to account for individual-specific and time-specific effects. We show that exposure to natural areas in general (including both nature areas and recreational areas) only slightly affects smartphone use relative to being in urban areas. However, we find that these effects differ substantially over the type of natural areas. While being in nature (e.g., forests or nature reserves) reduces smartphone screentime, texting, and calling by 4%, 6%, and 7%, respectively, being in recreational areas (e.g., parks or recreational grounds) does not affect smartphone screentime, but increases texting and calling by 11% and 17% respectively. Further, we show that the effect of being in a specific environment changes depending on how long time you have been in the specific environment and that nature reduces smartphone use more when users are staying still in nature, compared to moving through nature. Finally, we find that the users who spent the most time in nature also lowers their phone use the most when being in nature. In contrast, infrequent nature visitors increase their screentime when being in nature.

Smartphone use is socially contagious
In the third chapter, we show that smartphone use spread between individuals that are near each other. The spread of smartphone use only occurs between individuals who have a social relation. We, therefore, conclude that smartphone use spreads through social mechanisms. We show this by using data from a large-scale field study running for more than two years, which has the unique feature that it includes detailed information about nearby individuals. To causally identify the effect of one individual's screentime on nearby individuals, we use the arrival of text messages (SMS) as quasi-random natural experiments and track phone use for all co-present individuals before and after the arrival of the text message.

Showing that smartphone use is contagious has the potential to change the way we think about smartphone use. Because it is contagious, individuals' smartphone use goes from exclusively affecting the individual to also affecting nearby peers. Since there are indications that additional smartphone use is harmful to the individual, smartphone use arguably exhibits a negative externality, which would be an argument for regulation. This can be compared to second-hand smoking, where evidence of adverse effects on co-present individuals has led to heavy regulation.