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Effects of exposure to 50 Hz magnetic field of 1 mT on the performance of detour learning task by chicks.

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Che Y, Sun H, Cui Y, Zhou D, Ma Y. · 2007

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Twenty hours of daily magnetic field exposure impaired learning in chicks, suggesting chronic EMF exposure may affect cognitive function.

Plain English Summary

Summary written for general audiences

Researchers exposed young chicks to magnetic fields from power lines for 20 hours daily and tested their learning ability. Chicks with prolonged exposure showed significantly impaired learning and memory compared to unexposed chicks, suggesting extended magnetic field exposure may interfere with brain development.

Why This Matters

This study adds important evidence to the growing body of research showing that ELF magnetic fields can affect brain function, particularly learning and memory processes. The 1 milliTesla exposure level used here is quite high compared to typical household exposures (which range from 0.01 to 0.2 mT near appliances), but it's within the range found near power lines or in certain occupational settings. What makes this research particularly significant is the dose-response relationship it demonstrates - 20 hours of daily exposure caused cognitive impairment while 50 minutes did not, suggesting that duration of exposure matters as much as intensity. While this was an animal study, the brain mechanisms involved in learning and memory are remarkably similar across species, making these findings relevant for understanding potential human health effects from chronic EMF exposure.

Exposure Details

Magnetic Field
1 mG
Source/Device
50 Hz
Exposure Duration
20 h/day

Exposure Context

This study used 1 mG for magnetic fields:

Building Biology guidelines are practitioner-based limits from real-world assessments. BioInitiative Report recommendations are based on peer-reviewed science. Check Your Exposure to compare your own measurements.

Where This Falls on the Concern Scale

Study Exposure Level in ContextStudy Exposure Level in ContextThis study: 1 mGExtreme Concern - 5 mGFCC Limit - 2,000 mGEffects observed in the Severe Concern rangeFCC limit is 2,000x higher than this level
A logarithmic frequency spectrum from 10 Hz to 100 GHz showing where this study's 50 Hz exposure sits relative to common EMF sources.Where This Frequency Sits on the EMF SpectrumELFVLFLF / MFHF / VHFUHFSHFmm10 Hz100 GHzThis study: 50 HzCell phones~1 GHzWiFi2.4 GHz5G mm28 GHzLogarithmic scale

Study Details

The aim of this study is to observe Effects of exposure to 50 Hz magnetic field of 1 mT on the performance of detour learning task by chicks

we examined the effects of exposure to an extremely low-frequency magnetic field of 1 mT intensity o...

These results show that 20 h/day exposure to a low-frequency magnetic field induces a significant im...

Cite This Study
Che Y, Sun H, Cui Y, Zhou D, Ma Y. (2007). Effects of exposure to 50 Hz magnetic field of 1 mT on the performance of detour learning task by chicks. Brain Res Bull. 74(1-3):178-182, 2007.
Show BibTeX
@article{y_2007_effects_of_exposure_to_612,
  author = {Che Y and Sun H and Cui Y and Zhou D and Ma Y.},
  title = {Effects of exposure to 50 Hz magnetic field of 1 mT on the performance of detour learning task by chicks.},
  year = {2007},
  
  url = {https://www.sciencedirect.com/science/article/abs/pii/S0361923007001955},
}

Quick Questions About This Study

Yes, a 2007 study found that young chicks exposed to 50 Hz magnetic fields for 20 hours daily showed significantly impaired learning and memory compared to unexposed chicks. This suggests prolonged exposure to power line frequencies may interfere with brain development during critical growth periods.
Research shows 20 hours daily of 50 Hz magnetic field exposure significantly impairs learning ability in young chicks, while 50 minutes daily has no effect. This indicates duration matters greatly - brief exposures appear safe, but prolonged exposure may harm cognitive development.
Yes, exposure to 1 mT (millitesla) 50 Hz magnetic fields for 20 hours daily significantly impaired detour learning tasks in young chicks. This field strength, typical of high-voltage power lines, appears sufficient to interfere with normal brain development when exposure is prolonged.
Detour learning tests an animal's ability to navigate around obstacles to reach a goal, measuring spatial memory and problem-solving skills. Chicks exposed to 50 Hz power line magnetic fields for 20 hours daily showed significant impairment in this cognitive task compared to unexposed animals.
Based on 2007 research, 50-minute daily exposures to 50 Hz magnetic fields had no effect on learning ability in young chicks. Only prolonged 20-hour exposures caused significant cognitive impairment, suggesting brief exposures may not pose the same developmental risks as chronic exposure.