Abstract

With all developed modern technologies, smartphones combine most of them and make them easily accessible in daily life. Their development brought up discussions between the two sides of technology pessimists and optimists. The optimistic side argues that technology will lead to better knowledge processing, the other side warns about decreasing intelligence and negative impacts on education and society. The purpose of this study is to analyse the scientifically proven impact of smartphones on different cognitive abilities. The evaluation is done by comparing literature and study results. In conclusion there are positive as well as negative effects depending on the affected area. Ultimately, smartphones do not result in superior or inferior cognitive outcome but reshape different brain areas, particularly the prefrontal cortex.

Table of Contents

Introduction
What is Intelligence
How do we measure Intelligence
The Two Component Model
Flynn Effect & Anti-Flynn Effect
How do Smartphones affect Cognitive Abilities?
Passive Effect of Smartphones 
Language Skills
Working Memory and Attention
Long-Term Memory
Visual-Spatial Processing 
Decision-Making and Problem-Solving 
Conclusion 
Non-Mentioned Aspects
Bibliography 

Introduction

Modern technology has had a massive impact on the way we live over the past years. Especially in times of social distancing during the COVID-19 pandemic in the years 2020-2022 the smartphone became one of our main devices to stay connected with friends and family, receive the latest information and consume entertainment. It appears that in higher developed countries you cannot live without a smartphone anymore. As the latest study of Common Sense Media showed, teens (13-to-18-year-olds) in the U.S. spent around 8:39 hours daily in front of screens where 5:33 hours devoted to entertainment in 2021. Around 88% of them own a smartphone. (Rideout et al., 2022) The picture for parents is even worse with 9:22 hours of total screen time with 7:43 hours entertainment already in 2016. (Lauricella et al., 2016)

The daily influence of smartphones on our lives cannot be denied. Therefore, the remaining question for this study is: What effects does the regular use of smartphones have on our brains and our intelligence? One of the most important effects on intelligence in younger years is parental education. (Pietschnig, 2021, p. 187) Intelligence is likely inherited and formed by our environment, especially in schools. As smartphones are commonly known as distracting and addictive, on the one hand parents and teachers seem to have a hard time forming the intelligence of today’s children, on the other hand, more digitalisation in classrooms is a common goal for the European Union, (European Commission, 2018) as studies also show it is more effective to learn with digital devices. (Knogler et al., 2018)

Smartphones and their utilisation also show to be addictive. (Spitzer, 2018, pp. 127-129) It has not yet been confirmed whether there actually is an addiction to technology. The American Psychiatric Association (APA) and World Health Organisation (WHO) identified an Internet gaming disorder that results in similar looking brains as brains from people who suffer from other addictions. (Common Sense Media, 2020) Mobile gaming is one of the largest sectors in the application of smartphones. Studies indicate that addictive behaviours connected to smartphones have a significantly negative effect on academic performance. (Sunday et al., 2021) However, this conclusion can be drawn to any addictive behaviour.

This study aims to analyse which ones of these perspectives can be scientifically proven by evaluating how our brains and cognitive abilities are affected by the general usage of smartphones. By comparing study results and findings of scientists, the conclusion should show if smartphones will either improve or impair human intelligence and cognition.

What is Intelligence?

It has to be defined what is considered as intelligence in order to conclude study results on how smartphones affect human intelligence in terms of cognitive behaviour. Among scientists, there is no clear definition of intelligence. In most studies and articles from scientists analysing that specific topic, there only is a common ground on what factors influence human intelligence. Intelligence quotient (IQ), physical and mental health, higher education and life satisfaction show a common positive effect on intelligence. (Pietschnig, 2021, p. 46)

How do we measure Intelligence?

Until today the IQ is mostly used for comparing measured intelligence of humans. The psychologist William Stern defined IQ as intelligence age divided by life age multiplied by 100. A higher intelligence age as life age results in an IQ greater than 100 meaning the cognition is better developed as it would be in the current life age. (Pietschnig, 2021, pp. 65-79) The intelligence age is determined by testing the cognitive abilities of language skills, solving puzzles, short- and long-term memory, reasoning abilities, visual-spatial processing all compared to the processing speed. (Cherry, 2022)

However, the problem of this basic calculation is its assumption that intelligence always increases with age. This was resolved by adapting the perspective on intelligence measurement on two different components.

The Two Component Model

Raymond B. Cattell developed the hypothesis that our intelligence is made up of two major components: the fluid and crystallised intelligence. Fluid intelligence can be measured by evaluating the solving of tasks based on global rules like mathematics, for instance, while the crystallised intelligence is dependent on the environment and the received knowledge through education. For example, a child in Austria has a different geographical knowledge than an Indonesian one. (Pietschnig, 2021, pp. 50-54) Cattell concludes that the intersection of both equals a general factor of intelligence explained as a positive relation of all cognitive abilities while special skills are explained in further components.

Intelligence tests therefore best measure both components. While fluid intelligence usually decreases with age after reaching its high in the mid-20s the crystallised intelligence increases over time. David Wechsler concluded that the cognitive performance of an individual should be compared to the average skills of the surrounding. (Wechsler, 1939) 

Flynn Effect & Anti-Flynn Effect

The Flynn effect, named after the intelligence researcher James R. Flynn (2006) describes the phenomenon of IQ tests of the last century having measured that the average IQ has globally risen over time. In this test period, modern technology had a massive impact on our lives. It would only be natural to assume that computers and smartphones made us smarter. However, this could not be scientifically proven and is rather explained by a permanent reconstruction of IQ tests to keep 100 IQ points as the main comparable, the decreasing size of average families and the educational offer across the globe. Still, as the use of computers and smartphones also recorded positive effects on cognitive abilities, it can be considered as an influence on the Flynn effect. (Pietschnig, 2021, pp. 137-144)

Next to the Flynn effect there is also the opposite. After the turn of the millennium, it was observed that the average IQ decreased slowly over time. This phenomenon is known as the Anti-Flynn effect. In this specific timeframe the development of the smartphone played a main part in the evolution of life. Therefore, the Anti-Flynn effect proves the theories of culture pessimists in relation to the use of modern technology and smartphones. In Manfred Spitzer’s The Smartphone Epidemie (2018) the neuroscientist and psychiatrist especially took smartphones into account for the counteracting of the Flynn effect. Alternatively, as the Flynn effect cannot be explained mainly by the development of technology, the Anti-Flynn effect too is mainly impacted by other factors such as migration, cognitive saturation, an increasing life span and lower mortality. (Pietschnig, 2021, pp. 151-158)

Due to the unclarity of the direct impact of smartphones on both effects, the global effect of smartphones on human intelligence cannot be measured by IQ alone. The different cognitive abilities have to be analysed separately with all the different application patterns of smartphone technology respectively in order to measure their effects. As Flynn also concludes in an interview, increased IQ over time, does not indicate that contemporary generations have a better brain, but better skills in some areas measured in IQ tests. (Gellene, 2007)

How do Smartphones affect Cognitive Abilities?

Smartphones made it possible to unite all technological innovations on one device in our pockets. Wherever we go, we can access digital information on our smartphones in an instant. This results in the noticed daily usage of media. (Rideout et al., 2022) Because of this, companies aim to develop software that help us in our daily activities. 

As a basic component, phones in general enabled messaging and voice communication. GPS technology enabled us to navigate and access and process map information. The variety of software applications (apps) that can be installed on smartphones allows users to use smartphones for productivity, knowledge gain and entertainment, additionally. Ultimately, the Internet made browsing and social media available. All of these technologies are generally used multiple times a day by people owning a smartphone. (Beierle et al., 2020)

The mentioned technologies which are combined in smartphone usage affect our cognition in different ways. In literature smartphones are associated with a positive and a negative picture. Depending on which abilities we look at, the general opinion on smartphones can vary. An OECD study found that in countries with a higher amount of money spent on digitalisation and available technologies for schools, students had worse test results. (Spitzer, 2018, pp. 116-122) At the same time, the use of complex digital devices can be used to promote cognitive abilities. (Pietschnig, 2021, p. 141) The following chapters evaluate study results for each section of main cognitive abilities.

Passive Effect of Smartphones

Smartphones affect us not only when we use them. There is also one global aspect worth mentioning, which is energy consumption and climate change. While the energy consumption for charging smartphone batteries every day is barely having an effect on general power usage, the overall energy consumption drastically is. (Bridle, 2018, pp. 77-91) Streamed information needs to be provided on larger cloud-based server farms that use up a large amount of energy. For example, watching Netflix for 30 minutes on a phone equals 1.6 kg of CO2 emissions, which “is the same as driving almost four miles.” (Kamiya, 2020) The use of streaming software on smartphones therefore is contributing to a higher concentration of CO2 in our atmosphere.

In 2019 the atmosphere had a CO2 concentration of more than 400 parts per million, which is an increase by 11% since 2000. (Buis, 2019) The CO2 concentration in industrial cities is even higher with measurements of more than 500 ppm in the U.S. (Bridle, 2018, p. 90) A study from 2016 tested cognitive abilities from 24 probands after spending 6 hours working in different indoor environments. The results showed that cognitive functions were significantly better in green building conditions as in conventional ones. With a CO2 concentration of ~950 ppm the cognitive abilities were 15% lower as in green indoor environments with ~600 ppm on average of all testing days. In an atmosphere with ~1,400 ppm CO2 the results were 50% lower. (Allen et al., 2016) 

This indicates that with a consistent increase of CO2 concentration based on emissions of smartphones and other technologies, the atmosphere has the same effect on our cognition as a poorly ventilated office or classroom and results in an impairment of thinking clearly. (Bridle, 2018, p. 90)

Language Skills

The combination of the Internet and smartphones has a broad impact on our language and communication. People shifted from reading books and print newspapers to reading on digital screens. The Internet enabled cross-reading through browsing by linking to different web pages. One study measured brain activity while searching on Google comparing experienced web surfers with novices and found a much broader activity in the left front part of the brain of experienced surfers. Through continued Internet use the neural pathways in the left front also developed for the novices. (Small et al., 2019) Brain regions controlling language, reading, memory and visual abilities were activated during Internet browsing. Searching and browsing therefore seemed to have the same brain exercise effect as solving a crossword puzzle. (Carr, 2011, p. 122)

Moreover, text messaging transformed the way we express ourselves informally. In instant messaging services we tend to shorten the words we use, for example, we substitute “u” for “you”. (Thompson, 2013, p. 26) This phenomenon, known as textism, was also observed on Twitter as it formerly forced users to shorten their messages to less than 140 characters each. Studies indicate that knowledge and application of textism is not associated with poor written language outcomes. (Plester et al., 2009) Although there is a negative association between a greater use of textism and formal writing, the positive effect on informal writing must be mentioned. (Rosen et al., 2010) Concluding, it can be said that textism tends to increase verbal reasoning abilities.

Typing on smartphones also changed our aims when we write texts. Andrea Lunsford, a researcher for young people writing, observed that students who wrote texts for an audience wrote differently as when they delivered essays for school. Students adapted their writing to a potential debate or wanted to seem smarter for their readers. This effect is similar to writing texts for social media. There is always the possibility to comment on any given text, opening the discussion for everyone.  (Thompson, 2013, p.26) Given the importance of a positive reputation on social media, publishing bullet-proof arguments is essential for writers.

Another experiment analysed instant messaging in school context. The results showed a better cognitive engagement of students. The participants were more engaged sharing information as the control group. The mobility and synchronicity allowed knowledge gain in peer interactions which led to a deeper discussion of the learning materials. (Tang, 2022)

Using a mobile keyboard also increases writing performance with a combination of precise motion control and visual guidance. Using a keyboard enables visual proofreading while fast typing. This was analysed by a study which observed eye-finger movements of experienced mobile keyboard users when typing on different and manipulated keyboard interfaces. Any changed layout trained the probands memorization of the key positions and simultaneous proof-reading while typing additionally resulted in a higher confidence in the written text. When using a keyboard that randomly changes key positions after every key stroke, the results showed a quick glance at the typed character in the time of changing the layout. (Jiang et al., 2022) 

The development of smartphones also resulted in specific learning apps dedicated to language. Examples for language learning apps are Duolingo (2011) which is used by more than 1.2 billion individuals (Sharma, 2022) and Drops (2015). Both apps use gamification to engage users to learn by earning points. Moreover, they utilize the concept of microlearning, which serves learners with short training sequences adapted to flexible consuming behaviour and thus enable learning to become a routine. Official studies from Duolingo scientists confirm its approach to reach basic CEFR (Common European Framework of Reference) levels (Jiang & Pajak, 2022) which is also proven by independent studies that concluded with a positive effect on learning engagement and comparing the app usage to an actual semester of language learning. (Bennani & Mosbah, no date)

Working Memory and Attention

Our working memory and attention are crucial to keep focus on a task. When we are focussed, the working memory is engaged with the dorsolateral prefrontal cortex which further connects to our long-term memory. (SoP, 2017) When the information flow overloads its capabilities our brain is distracted and cannot connect perceived information to data in our long-term memory. Thus, we cannot learn effectively from the information we gathered. Furthermore, it becomes harder to distinguish relevant and irrelevant data. (Carr, 2011, p. 125)

Heavy multitasking results in a greater activity in the right prefrontal regions of the brain, which are activated in response to distractor stimuli. Heavy media multitaskers were found to perform worse in task-switching tests (Firth et al., 2019). In addition, students who watched lectures while sending text messages did roughly 19 percent worse on a following test about the learning material. (Thompson, 2013, p. 49) Thad Starner even raises the theory “checking email while you talk to someone you lose 40 IQ points”. (Thompson, 2013, p. 51)

When watching office workers, Gloria Mark concluded that after being interrupted it takes about 25 minutes to return to the original work. (Thompson, 2013, p. 49) In a study, students were distracted by a one-time fake ringing of a smartphone during a lecture. The evaluation showed that the fake ringing caused students to less likely pay attention and memorize the presented information of the lecturer compared to the control group. (Spitzer 2018, pp. 64-68) 

In human history brains were wired to alert us when there were visual or auditory changes in the environment to warn us from danger like wild animals. This characteristic has contributed to our selective attention for smartphone notifications. Each interruption of smartphone messages is considered to bring valuable new information, while we willingly accept the loss of concentration. (Carr, 2011, p. 134)

Additionally, even not using a smartphone has an impact on our attention. In an experiment conducted by Ward et al. (2017) it was evaluated that merely the presence of a smartphone on our desk affects our working memory. Same as office workers were found to click “check for emails” while the email software automatically notifies you to new emails (Carr, 2011, p. 132), students were found to frequently check their phone when it did not ring or after a phantom ring. The phantom ring describes the phenomenon of perceiving a sound or a vibration even though there was none.

Phantom rings resulted from an extensive use of smartphones. (Gupta et al., 2016) The more we experience vibrations and link it to an emotional positive outcome as “someone thinks about me” the more sensitive the transmission of signals become in body parts that we usually are in contact with our smartphone. The occurrence of phantom vibrations was early proven by analysing doctors using pagers. When carrying these devices for at least six hours a day the chance of experiencing phantom vibrations increased by 30%. (Spitzer, 2018, pp. 190-193) Still, smartphone users did not mention phantom rings as bothersome. This behaviour is not only expected to become a cause of concern for mental health, (Deb, 2014) it also affects our attention as the distraction outcome of checking our phone remains the same.

Digital displays further contain a higher amount of blue light through its background light. The blue light share of digital screens affects our unintentional and intentional attention shift towards digital screens. A study found that blue light delays unintentional attention shifts. (Yang et al., 2023) On the contrary, blue light environments show enhancements of working memory but reduced attentiveness. (Jung & Murphy, no date)

Long-Term Memory

Our long-term semantic memory is our factual knowledge centre. The Internet and the constant availability of smartphones replaced parts of it. While our brain tries to connect a question to an answer stored in our semantic memory we likely experience the Tip-of-the-tongue syndrome. Instead of allowing our brain to make this connection, we use the Internet to find the answer more quickly. (Thompson, 2013, p. 42)

As an experiment from Betsy Sparrow showed, students who were told that information would not be saved were more likely to recall a fact than students who were informed where the information on a computer has been stored. Contrarily, the students who were informed about saving, stated to be confident to know where to find the information again. (Thompson, 2013, pp. 46-48) The experiment indicates that using a smartphone changes our information processing into the direction of knowing where to find information in an instant rather than knowing it by heart. This form of cognitive offloading also increased the ability to focus on not immediately retrievable information. (Firth et al., 2019)

A phase of quietness and relaxation is essential to our brain. Deep thinking processes highly involve the connection of information from schemes stored in our long-term memory. Studies revealed that people developed a stronger long-term memory when spending time in a quiet setting than in a busy street. Similar to streets is the experience of a constant buzz of smartphones. (Carr, 2011, pp. 219) Further, distractions caused by smartphones during the time of transferring information from our short-term memory to our long-term memory are negatively affecting the processing of that information and its placement in a scheme to call the information when needed. (Seal, 2022)

In addition, the stimulation of blue light results in our brain suppressing melatonin to make our body awake, same as it would do in daylight. (Anon, 2020) Studies indicate that spending time in front of digital screens at night times influences our sleeping behaviour by delaying or interrupting the sleeping cycle. (Rafique et al., 2020) A phase of deep and slow wave sleep is also needed to better process and transfer information into our long-term memory. (Walker, 2009)

Using smartphone apps that aim to improve our memory is also proven to have a positive effect on our long-term memory, as indicated in a study testing a training app on older adults. (Oh et al., 2017) However, the general usage of smartphones and its continuing effects on our long-term memory processing cannot be evaluated properly, as it is hardly possible to have a control group. Such a study would mean to analyse people who are not raised with or do not have extensive access to any form of online information. (Thompson, 2013, p. 49) 

Visual-Spatial Processing

Visual-spatial processing is the cognitive ability to interpret visual information in order to find orientation in the physical environment. This skill is essential, for example, to read maps and navigate through complex environments. A research of Eleanore Maguire on brains of London cab drivers revealed an increased grey matter volume in the hippocampal area of their brains. As cab drivers, they had to memorise a lot of data based on maps and visual impressions of the road network. Maguire already speculated in 2006 that GPS usage will make their brains less interesting. (Carr, 2011, p. 212)

Smartphones with GPS affect our spatial memory, our cognitive map, consisting of information bits forming our knowledge about physical locations. (Grabar, 2014) Heavy GPS users were found to have a less developed spatial memory and its strategical use. (Dahmani & Bohbot, 2020) Studies confirm the worries of Maguire and conclude that GPS usage correlates with a negative impact on the hippocampus and reduced grey matter in this area.

Smartphones are also widely used for playing video games. Nearly 40% of teenagers in the U.S. play video games daily on smartphones. (Rideout, 2022) Next to puzzle solving skills, video games also require a high visual attention and processing. (Pietschnig, 2021, p.141) Studies found that reading performance increased with playing action video games. The capacity of processing multiple visuals simultaneously resulted in processing more letters in parallel with strings. (Antzaka et al., 2017) Furthermore, increased spatial abilities through gaming are associated with success in maths and science. (Feng, 2007)

Decision-Making and Problem-Solving

The skills to solve problems and make decisions require all cognitive fields that were mentioned in the previous chapters. Activities in the prefrontal and parietal cortex such as visual perception, working memory and long-term memory play a part in the process of decision-making. (SoP, 2018) With the usage of smartphones we externalise problem-solving and reduce our ability to build knowledge structures. (Carr, 2011, p. 216) 

Our brain is wired to solve complex problems with the least amount of cognitive effort. This is particularly the case when we are under time pressure. It can become easier to consult our smartphone than start the process of deep thinking about a solution. This results in the phenomenon of Automation bias. The evaluated results from our smartphone tend to be more trusted as well. Artificial intelligence software on smartphones such as large language models or speech assistants are likely to be trusted when consulting them to find solutions. (Jones-Jang, 2022)

Taking decisions on smartphones was also found to be more irrational and short-sighted than taking them on other devices, tested with decision-making in a financial context. As smartphones are omnipresent in our daily routine and used for short operations, there is a correlation with shorter decision-making processes. (Wang et al., 2023) Additionally, heavy and regular users of smartphones also showed more impulsive decision-making than users with a low smartphone usage. Smartphone behaviour and gambling especially increased our decision-making towards immediate reward rather than long-term reward solutions and taking risks of immediate loss to avoid losing outcome in the future. (Tang et al., 2017)

Smartphones also impacted one key aspect of why humans succeeded in evolution: cooperation. (Harari, 2017, p.183) Smartphones helped to form collective intelligence. With the development of messaging networks and social media, we have a constant connection with other humans who are able to collaborate. Solving problems in isolation has transformed into letting problems be solved by the collective. Instead of measuring problem-solving abilities to define intelligence, the skill of defining problems in a way to let people contribute effectively to the solution has to be assessed. (Thompson, 2013, pp. 60-62) 

Conclusion

This study aimed to conclude if smartphones are making us more intelligent or less intelligent. As the previous chapters showed, there are both positive and negative effects of smartphone usage. The overarching aspect is that smartphones shape our brains and cognitive skills differently than other technologies. 

Considering that the Internet was already proven to promote cursory reading, hurried and distractive thinking by stimulating our brain with repetitive, intensive, interactive, and addictive tasks, (Carr, 2011, p. 116) smartphones additionally fuel these effects even more. Therefore, smartphones have significant negative effects on our attention, working memory and thus decision-making.

The ubiquitous presence of smartphones not only negatively affects our working memory and attention span, it also reduces grey matter in brain regions we used for understanding complex visuals as seen in the example of using GPS rather than maps. Furthermore, as the human brain is wired to make the least cognitive efforts in solving problems, smartphones lead to an increase of irrational and short-sighted decisions and ultimately Automation bias which can be considered as dangerous in aspects of information processing and life-threatening decisions including medical treatments. (Harari, 2017, pp. 460-466)

Smartphones and the usage of social media shifted our writing skills from formal writing to informal knowledge transfer, forming collective intelligence in order to solve problems. Both conclude to increase knowledge collectively rather than for the individual, as the individual long-term memory transforms into memorising where information can be found when needed rather than memorising the actual information.

Measured fluid intelligence therefore has to change to these transformations to be taken into account for measuring global effects like the Anti-Flynn effect. Based on former IQ tests, smartphone technology is certainly a factor for decreasing common IQ level but cannot explain decreases in what we comprehend as intelligence which in the end comes down to solving complex problems. The current developments of artificial intelligence in the form of large language models also available in smartphone software potentially will increase this behaviour even more including higher Automation bias.

Positives can be found analysing the usage of apps designed for learning purposes as for languages, while adapting to the transformed cognitive behaviours when using smartphones. Shorter learning sequences that form a routine by keeping learners motivated can therefore impact fluid intelligence by better memorising the learned information. 

Writing on smartphones further improves motion control while processing visual inputs simultaneously. In addition, playing video games on smartphones has a positive effect on our visual-spatial attention. Used in the right way, it has the potential to speed up our visual processing for multiple visual impressions.

Overall, activities on smartphones mostly affect our prefrontal cortex. On one hand, it enhances the lower-level abilities such as coordination and visual attention. Also, while flooding the cognitive load, our brains most likely will expand these areas to develop new skills like handling multiple conversations in multiple media simultaneously. On the other hand, this technology leads to individuals knowing less, while the collective provides more knowledge and in addition, decreases our ability to process complex schemes of information in our long-term memory and apply the connections appropriately to new cases.

However, a scientifically proven conclusion on how smartphones affect the development of a human brain cannot be drawn, as it is not ethically possible to perform long-term studies with a control group that is cut off from smartphone technology and additionally also from passive effects, such as a higher concentration of CO2 in the atmosphere. In the end, further studies should focus on how we can counteract the negative aspects by providing guidelines for using these devices judiciously in education, as a cancellation of smartphones and included technologies most likely will not be feasible in the future. 

Non-Mentioned Aspects

The analysis only took the regular smartphone usage into account. Other theses and studies conclude that smartphones also lead to forms of addiction depending on what we do with these devices. Addiction is also proven to affect our cognitive behaviour and furthermore reduce our willingness to learn and significantly affect academic performance. (Gupta et al., 2016) However, smartphone addiction has to be analysed on its own and compared to other addictive behaviours as smartphones per se are not addictive but the software used on the devices.

Finally, smartphone usage for consuming information is considered to have a huge impact on our society. The easy distribution of information without gatekeeping paved the way for harmful information and propaganda. Additionally, smartphones make it easier to stay isolated while receiving all needed information for daily life. As this does not have effects on our cognitive abilities, it is considered to lead to passive effects such as depression or social impairments seen by younger generations. (Spitzer, 2018, 137-139)

Bibliography

Anon, (2020) Blue light has a dark side. Harvard Health Publishing. Available at:  https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side (Accessed: 27.03.2023)

Antzaka, A., Lallier, M., Meyer, S. et al. (2017) Enhancing reading performance through action video games: the role of visual attention span. Sci Rep 7, 14563. https://doi.org/10.1038/s41598-017-15119-9

Allen, J. G., MacNaughton, P., Satish, U., Santanam, S., Vallarino, J., & Spengler, J. D. (2016). Associations of Cognitive Function Scores with Carbon Dioxide, Ventilation, and Volatile Organic Compound Exposures in Office Workers: A Controlled Exposure Study of Green and Conventional Office Environments. Environmental health perspectives, 124(6), 805–812. https://doi.org/10.1289/ehp.1510037 

Beierle, F., Probst, T., Allemand, M., Zimmermann, J., Pryss, R., Neff, P., Schlee, W., Stieger, S., & Budimir, S. (2020). Frequency and Duration of Daily Smartphone Usage in Relation to Personality Traits. Digital Psychology, 1(1), 20–28. https://doi.org/10.24989/dp.v1i1.1821

Bennani, W. & Mosbah, R. (no date) Investigating the Effectiveness of the Duolingo Platform in Developing Learners’ Vocabulary and Grammar Acquisition Case of CEIL Adult Beginner EFL Learners. TRANS Nr. 22. Available at: https://www.inst.at/trans/22/investigating-the-effectiveness-of-the-duolingo-platform-in-developing-learners-vocabulary-and-grammar-acquisition-case-of-ceil-adult-beginner-efl-learners/ (Accessed: 01.04.2023)

Bridle, J. (2018). New Dark Age. Technology and the End of the Future. London: Verso.

Buis, A., (2019) The Atmosphere: Getting a Handle on Carbon Dioxide – Sizing Up Humanity’s Impacts on Earth’s Changing Atmosphere​: A Five-Part Series. (09.10.2019) NASA’s Jet Propulsion Laboratory. Available at: https://climate.nasa.gov/news/2915/the-atmosphere-getting-a-handle-on-carbon-dioxide/ (Accessed: 01.04.2023)

Carr, Nicholas G. (2011). The shallows. What the Internet is doing to our brains. New York, Norton

Cherry, K. (2022) What Is an IQ Test?. (14.11.2022) Verywell Mind. Accessible at: https://www.verywellmind.com/how-are-scores-on-iq-tests-calculated-2795584
(Accessed: 25.03.2023)

Common Sense Media. (2020). Is Internet addiction real? (04.06.2020) Available at: https://www.commonsensemedia.org/articles/is-Internet-addiction-real (Accessed: 25.03.2023)

Dahmani, L. & Bohbot, Véronique D. (2020) Habitual use of GPS negatively impacts spatial memory during self-guided navigation. Sci Rep 10, 6310. https://doi.org/10.1038/s41598-020-62877-0

Deb, Amrita. (2014). Phantom vibration and phantom ringing among mobile phone users: A systematic review of literature. Asia-Pacific psychiatry: official journal of the Pacific Rim College of Psychiatrists. 7. 10.1111/appy.12164.

European Commission (2018) COMMUNICATION FROM THE COMMISSION TO THE EUROPEAN PARLIAMENT, THE COUNCIL, THE EUROPEAN ECONOMIC AND SOCIAL COMMITTEE AND THE COMMITTEE OF THE REGIONS. on the Digital Education Action Plan. Available at: https://eur-lex.europa.eu/legal-content/EN/TXT/PDF/?uri=CELEX:52018DC0022&from=EN (Accessed: 25.03.2023)

Feng, Jing & Spence, Ian & Pratt, Jay. (2007). Playing an Action Video Game Reduces Gender Differences in Spatial Cognition. Psychological science. 18. 850-5. 10.1111/j.1467-9280.2007.01990.x.

Firth, J., Torous, J., Stubbs, B., Firth, J. A., Steiner, G. Z., Smith, L., Alvarez-Jimenez, M., Gleeson, J., Vancampfort, D., Armitage, C. J., & Sarris, J. (2019). The „online brain“: how the Internet may be changing our cognition. World psychiatry: official journal of the World Psychiatric Association (WPA)

Flynn, J.R. (2006). Tethering the elephant: Capital cases, IQ, and the Flynn effect. Psychology, Public Policy, and Law. Vol. 12, No. 2, 170 –189

Freuler, R., (2018) Mit digitalen Geräten lernen Schüler besser – und lieber. NZZ (26.01.2018) Available at: https://magazin.nzz.ch/wissen/mit-digitalen-geraeten-lernen-schueler-besser-und-lieber-ld.1351146?reduced=true (Accessed: 25.03.2023)

Gellene, D. (2007) IQs rise, but are we brighter? (Oct. 27, 2007) Los Angeles Times. Available at: https://www.latimes.com/archives/la-xpm-2007-oct-27-sci-iq27-story.html (Accessed: 02.04.2023)

Grabar, H., (2014) Smartphones and the Uncertain Future of ‚Spatial Thinking‘. Bloomberg. (09.09.2014) https://www.bloomberg.com/news/articles/2014-09-09/smartphones-and-the-uncertain-future-of-spatial-thinking (Accessed: 26.03.2023)

Gupta, N., Garg, S., & Arora, K.S. (2016). Pattern of mobile phone usage and its effects on psychological health, sleep, and academic performance in students of a medical university. National Journal of Physiology, Pharmacy and Pharmacology, 6, 132-139.

Harari, Y. (2017). Homo Deus. A Brief History of Tomorrow. London: Harvill Secker.

Jiang, X., Jokinen, J. P. P., Oulasvirta, A., & Ren, X. (2022). Learning to type with mobile keyboards: Findings with a randomized keyboard. Computers in Human Behavior, 126, 106992. doi: 10.1016/j.chb.2021.106992

Jiang, X. & Pajak, B. (2022) Reading and Listening Outcomes of Learners in the Duolingo English Course for Spanish Speakers. Duolingo Research Report DRR-22-0. Available at: https://duolingo-papers.s3.amazonaws.com/reports/duolingo-english-efficacy-whitepaper.pdf (Accessed: 01.04.2023)

Jones-Jang, S. M. & Park, Y. J. (2022). How do people react to AI failure? Automation bias, algorithmic aversion, and perceived controllability. Journal of Computer-Mediated Communication, 28(1), zmac029. doi: 10.1093/jcmc/zmac029.

Jung, M. & Murphy, D. (no date). Go Blue: The Effects of Blue Light on Memory. Psychology in Action. Available at: https://www.psychologyinaction.org/2022-1-17-go-blue-the-effects-of-blue-light-on-memory/(Accessed: 27.03.2023)

Kamiya, G., (2020) The carbon footprint of streaming video: fact-checking the headlines. (11.12.2020) International Energy Agency. Accessible at: https://www.iea.org/commentaries/the-carbon-footprint-of-streaming-video-fact-checking-the-headlines (Accessed: 25.03.2023)

Knogler, M., Wiesbeck, A. B. & CHU Research Group (2018). Kollaboratives Lernen und mobile digitale Geräte: Eine wirksame Kombination? www.clearinghouse-unterricht.de, Kurzreview 15.

Lauricella, A. R., Cingel, D. P., Beaudoin-Ryan, L., Robb, M. B., Saphir, M., & Wartella, E. A. (2016). Common Sense census: Plugged-in parents of tweens and teens. San Francisco, CA: Common Sense Media.

Oh, S. J., Seo, S., Lee, J. H., Song, M. J., & Shin, M. S. (2017). Effects of smartphone-based memory training for older adults with subjective memory complaints: a randomized controlled trial. Aging & Mental Health, doi: 10.1080/13607863.2016.1274373.

Oluwafemi J. Sunday, Olusola O. Adesope, Patricia L. Maarhuis. (2021). The effects of smartphone addiction on learning: A meta-analysis. Computers in Human Behavior Reports, Volume 4, 100114, ISSN 2451-9588, Available at: https://doi.org/10.1016/j.chbr.2021.100114.

Pietschnig, J. (2021). Intelligenz. Wie klug sind wir wirklich?. Salzburg: Ecowin.

Plester, B., Wood, C., & Bell, V. (2008). Txt msg n school literacy: does texting and knowledge of text abbreviations adversely affect children’s literacy attainment? Literacy, 42(3), 137-144. doi: 10.1111/j.1741-4369.2008.00489.x

Rafique N, Al-Asoom LI, Alsunni AA, Saudagar FN, Almulhim L & Alkaltham G. (2020) Effects of Mobile Use on Subjective Sleep Quality. Nat Sci Sleep. doi: 10.2147/NSS.S253375. PMID: 32607035; PMCID: PMC7320888.

Rideout, V., Peebles, A., Mann, S., & Robb, M. B. (2022). Common Sense census: Media use by tweens and teens, 2021. San Francisco, CA: Common Sense.

Rosen, Larry & Chang, Jennifer & Erwin, Lynne & Carrier, Mark & Cheever, Nancy. (2010). The Relationship Between „Textisms“ and Formal and Informal Writing Among Young Adults. Communication Research – COMMUN RES. 37. doi: 10.1177/0093650210362465.

Seal, R. (2022) Is your smartphone ruining your memory? A special report on the rise of ‘digital amnesia’. The Guardian. Available at:  https://www.theguardian.com/global/2022/jul/03/is-your-smartphone-ruining-your-memory-the-rise-of-digital-amenesia (Accessed: 26.03.2023)

Sharma, H. (2022) „Duolingo’s language-learning educational services have benefited millions of people across the globe.“. Impaakt (04.03.2022) Available at: https://www.impaakt.com/blog/impact-analysis-duo-lingo-language-learning-impact (Accessed: 27.03.2023)

Small, G. W., Moody, T. D., Siddarth, P., & Bookheimer, S. Y. (2009). Your brain on Google: patterns of cerebral activation during Internet searching. The American journal of geriatric psychiatry : official journal of the American Association for Geriatric Psychiatry, 17(2), 116–126. https://doi.org/10.1097/JGP.0b013e3181953a02 

SoP (2017), Prefrontal Cortex. Dahlitz Media (04.01.2017) Available at: https://www.thescienceofpsychotherapy.com/prefrontal-cortex/  (Accessed: 26.03.2023)

SoP (2018), Parietal lobes. Dahlitz Media (01.10.2018) Available at: https://www.thescienceofpsychotherapy.com/glossary/parietal-lobes/ (Accessed: 27.03.2023)

Spitzer, M. (2018). Die Smartphone Epidemie. Gefahren für Gesundheit, Bildung und Gesellschaft. Stuttgart: Klett-Cotta.

Tang, Y., Hew, K.F., (2022) Effects of using mobile instant messaging on student behavioral, emotional, and cognitive engagement: a quasi-experimental study. Int J Educ Technol High Educ 19, 3. https://doi.org/10.1186/s41239-021-00306-6

Tang, Z., Zhang, H., Yan, A. & Qu, C. (2017) Time Is Money: The Decision Making of Smartphone High Users in Gain and Loss Intertemporal Choice. Front Psychol. doi: 10.3389/fpsyg.2017.00363. PMID: 28344568; PMCID: PMC5344929.

Thompson, C. (2013). Smarter Than You Think. How technology is changing our minds for the better. [Apple Books version] London: William Collins. 

Walker, Matthew P. (2009) The role of slow wave sleep in memory processing. J Clin Sleep Med. S20-6. PMID: 19998871; PMCID: PMC2824214.

Wang, T., Chen, W.-F., Wang, X., & Fan, X. (2023). Smartphone use increases the likelihood of making short-sighted financial decisions. Journal of Pacific Rim Psychology, 17. https://doi.org/10.1177/18344909221147782 

Ward, A. F., Duke, K., Gneezy, A., & Bos, M. W. (2017). Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity. Journal of the Association for Consumer Research, 2(2), 140-154. doi:10.1086/691462

Wechsler, D. (1939). The measurement of adult intelligence. Williams & Wilkins Co. https://doi.org/10.1037/10020-000

Yang, CC., Tsujimura, Si. & Yeh, SL. (2023) Blue-light background impairs visual exogenous attention shift. Sci Rep 13, 3794. https://doi.org/10.1038/s41598-022-24862-7