Lighting Quality and Clinical Memory Retrieval Study

Psychological researchers wanted to investigate whether high-frequency fluorescent lighting flicker (which is often imperceptible but can cause physiological strain) affects short-term memory retrieval in medical trainees.

An opportunity sample of 30 junior doctors was recruited from a teaching hospital. The sample consisted of 18 females and 12 males, aged 24–28 years. The participants were randomly allocated to either the 'flicker' lighting condition or the 'stable LED' lighting condition, with 15 participants in each group.

In both conditions, participants sat in a simulated clinic room and were given 5 minutes to memorise a patient's complex case history containing 20 distinct clinical symptoms.

• In the 'flicker' condition, the room was illuminated by older fluorescent tubes with a high-frequency ballast that produced a micro-flicker.
• In the 'stable LED' condition, the room was illuminated by modern, solid-state LED panels.

Afterwards, all participants completed a free-recall test where they had to list as many of the 20 symptoms as possible.

Before starting, the researchers told the participants that the study was evaluating the clarity and font legibility of a new electronic health record (EHR) layout. The true focus on lighting quality was not mentioned. At the end of the testing session, all participants were fully debriefed.

The recall scores (out of 20) yielded the following results:

• 'Flicker' condition: Mean = 11.40, Standard Deviation = 3.12
• 'Stable LED' condition: Mean = 14.80, Standard Deviation = 1.45