A researcher wanted to investigate how different auditory distractors affect cognitive focus and selective attention. She conducted an experiment in a highly controlled, soundproof laboratory cubicle where participants were randomly allocated to one of two groups:

• Group 1 performed a complex 3D mental rotation task (determining if pairs of three-dimensional geometric shapes were identical or mirrored) while listening to steady white noise through high-isolation headphones.
• Group 2 performed the identical 3D mental rotation task while listening to a pre-recorded multi-person conversation from a bustling coffee shop through the same headphones.

The researcher recorded the time taken (in milliseconds) to correctly identify the shapes. She found that Group 2 was significantly slower than Group 1.

The investigation of selective attention outlined above was a laboratory experiment.