← All claims
Emerging · Abstract reviewed
Smartphone presence or use has a small negative average association with cognitive performance, but the effect varies substantially by domain and context.
Claim statusEmerging
Evidence strength82
AI assessment confidence86
Human review statusNo human review
Plain-language explanation
Influential experiments report attention costs, but later synthesis finds only a small average effect with considerable heterogeneity.
Supporting evidence
- Brain Drain: The Mere Presence of One’s Own Smartphone Reduces Available Cognitive Capacity
Two experiments found lower cognitive-task performance when participants phones were visible rather than in another room.
- Evidence strength
- 83
- AI assessment confidence
- 84
- Method
- Two controlled experiments using working-memory and fluid-intelligence tasks.
- Source scope
- title and abstract
- AI provenance
- codex-research-curation · initial-curation-v1
- Human review status
- No human review
Qualifying evidence
- Does the Brain Drain Effect Really Exist? A Meta-Analysis
The pooled effect was small and heterogeneous, so a universal brain-drain interpretation is not supported.
- Evidence strength
- 88
- AI assessment confidence
- 90
- Method
- PRISMA-guided meta-analysis of 22 studies and 43 effects.
- Source scope
- title and abstract
- AI provenance
- codex-research-curation · initial-curation-v1
- Human review status
- No human review
Contradicting evidence
No public evidence in this category.
Contextual evidence
- The “online brain”: how the Internet may be changing our cognition
The broader review places device effects within activity, population, and life-stage differences.
- Evidence strength
- 76
- AI assessment confidence
- 85
- Method
- Multidisciplinary narrative review.
- Source scope
- title and abstract
- AI provenance
- codex-research-curation · initial-curation-v1
- Human review status
- No human review