The AEIOU method came from Dev Patnaik in his book Needfinding: Design Research and Planning. I first learned about it from Designing Your Life by Burnett and Evans.

The acronym stands for:

Activities

• What were you doing?
• Was it structured or unstructured?
• What was your role in the activity?

Environments

• Where were you?
• What kind of place was it?
• How did the place make you feel?

Interactions

• What or who were you interacting with?
• Was the interaction novel or familiar?
• Was the interaction formal or informal?

Objects

• What objects were you interacting with?
• What objects helped you feel engaged?

Users

• Who else was there during the activity?
• How did they make the experience positive or negative?

References

Burnett, B., & Evans, D. (2016). Designing Your Life: How to Build a Well-lived, Joyful Life. Alfred A. Knopf.