In one of the most cited studies on technology and cognition, Ward et al. (2017) demonstrated that the mere presence of a smartphone — even when it is face-down and turned off — significantly reduces available cognitive capacity.
Across two experiments with nearly 800 participants, the researchers found that individuals who had their smartphones on their desks performed significantly worse on tests of working memory and fluid intelligence compared to those whose phones were in another room. Critically, participants were not aware of any cognitive impairment — they believed they performed equally well regardless of phone placement.
Key Finding
The cognitive cost is driven by the attentional resources required to inhibit the urge to check one's phone. Even without any notifications, the phone acts as an "attentional magnet" that diverts limited cognitive resources away from the task at hand.
Implications for AI
This finding extends directly to AI assistants. As AI tools become constantly available — on phones, laptops, wearables — the mere knowledge that an AI could provide answers may reduce our willingness to engage in deep, effortful thinking. The cognitive offloading effect becomes automatic and unconscious.
Source
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