Key takeaways: Object permanence is the understanding that objects and people still exist when you can’t see them. Babies show signs of it in the first year, and by about 9 months many look for objects that drop out of sight, a CDC milestone. It’s linked to separation anxiety and the delight of peekaboo.
Peekaboo isn’t just fun. It’s helping your baby learn a big idea.
What Is Object Permanence?
It’s the understanding that things exist even when they’re hidden. Psychologist Jean Piaget described this skill developing over the first two years. Later research, such as studies by Renée Baillargeon, suggested babies may understand some of it earlier than Piaget thought.
How It Develops
- Early months: out of sight is often out of mind.
- Around 4 to 8 months: babies may look for a partly hidden toy.
- By about 9 months: many look for objects dropped out of sight (CDC milestone).
- By about 12 months: many look for things they see you hide (CDC milestone).
Why Babies Love Peekaboo
Peekaboo plays with the idea of things disappearing and reappearing, and babies find it delightful. Smiling or laughing at peekaboo is on the CDC’s 9-month checklist.
The Link to Separation Anxiety
Once babies understand that you exist when you leave, they may protest when you go. This is normal.
Games to Try
- Peekaboo with your hands or a cloth.
- Hide a toy partly under a blanket, then fully.
- Drop and find: let your baby drop toys and find them.
- Pop-up toys.
- Ball drop tubes.
- Hide-and-seek behind furniture, peeking out.
The Bottom Line
Object permanence is a key milestone. Play peekaboo and hiding games to help your baby learn and have fun.
Want more support for your baby’s first year? My book, From First Breath to First Birthday, is available on Amazon.
Sources
- Centers for Disease Control and Prevention. Important milestones: your baby by 9 months; by 1 year. https://www.cdc.gov/ncbddd/actearly
- Baillargeon R. Object permanence in 3½- and 4½-month-old infants. Dev Psychol. 1987;23(5):655-664.
- Piaget J. The Construction of Reality in the Child. Basic Books; 1954.
This article is for general education and is not a substitute for individualized medical advice. Always talk with your baby’s health care provider or your own provider about your specific situation. If you think your baby or you may have a medical emergency, call 911.
