My 4 (almost 5) year old daughter is currently on a kick with baby dolls. It's all she wants to play with at the moment. She wants to take her dolls to the park, for example, and play with them rather than engage with other kids that might be there. My wife thinks it's a problem and insists she stop playing with the dolls, not take them to the park and go do something else causing some friction with our daughter. I'm not so sure how much we should worry about it.
To expand your daughter's range of toys, build on the toy she likes.
(Aren't you lucky that it is imagination-based -- and not TV or computer. Do note that if you remove one thing, it will be replaced with another thing. When you consider the big picture -- dolls are a pretty good choice!)
On edit (thanks the_lotus) All these activities are done by or with your child.
- Make doll furniture -- from wood, clean cardboard or food containers.
- Make a doll house or area -- paint scenes or backdrops.
- Make doll clothing -- white fabric can also be painted or designed.
- Make a car or truck or bus for the dolls from found materials.
- Read stories about dolls and then make up and illustrate her own.
- Figure out a way for a doll to be in a bike carrier 'baby' seat -- to encourage outdoor play and exercise.
- Make a doll 'snuggy' so that she can wear one doll and take her on the swing, the slide and so on.
- Being a good mummy means she needs to read to her babies, and keep their area clean.
- She can play 'teacher' or 'parent' or 'firefighter' and teach, parent or rescue her doll.
- She can make up plays and you can shoot movies on your phone.
- She can dance with her babies.
- This list is endless -- you can add in anything and not hassle your daughter about liking dolls. If you don't make a big deal out of it, you may find she moves on to something else, all on her own.
My brother was obsessed with cars. He still is! He has a car dealership. It doesn't have to be 'bad' to be obsessed.
Yes, it's okay (and very, very common) for a child to focus on one type of toys for a period of time. My sons and their friends have variously focused on trains, cars, ponies, Pokémon, one specific type of animal, etc., often for months at a time.
Rather than worry about the kind of toy, I would focus on the kind of play. As long as there is a mixture of creative play, active play, and hand-eye coordination training, she's doing fine. Dolls are great for that because they involve all of the above. Some examples:
- Creative play: making up stories involving the dolls, setting up imaginary situations with the dolls, using dress up clothes with the dolls
- Active play: taking the dolls to the park, running around with the dolls, putting the doll on a trike
- Hand-eye coordination: dressing the dolls, moving the dolls around in different setups, making a house for the dolls
She'll move on to something else at some point, particularly as she is aging into the age group where she's going to play with other kids more rather than parallel play. 4-5 years old is where that usually starts. Once she's in school, these things will bounce around as her friends' interests change as well as her own.
It might be a phase. She might start playing with something else very shortly.
But if you can introduce other concepts that dovetail into what she is interested in, then you are coming out ahead. Like @Willow says, get her interested in building things for her dolls. Maybe use the dolls to introduce more familiarity with a variety family units. The sky is the limit with imaginative play.
Why is this a problem? There's nothing inherently bad about her playing with dolls. So she only plays with one kind of toy. So what? Children go through phases like this all the time, where they get obsessed with one thing. One of my sons had a period when he was around 12 or so when he became obsessed with the Titanic. He spent all his free time reading books about the Titanic, watching TV shows and movies about the Titanic. Building a model of the Titanic. A few months later the phase passed and he was on to something else. One of my daughters got obsessed with Furbees for a while. Etc. My kids when through lots of phases like this. All of them passed within a few months or a year or so.
What do you do for entertainment? Have you ever had a period where you got interested in something and spent all your free time doing that one thing for a while? I certainly have. Like I might buy a new computer game that I really like, and then for a couple of months play it endlessly. I recall my brother had a period in his 20s when he became obsessed with camping and wilderness survival for several years. Etc.
What would be gained by forcing her to play with a different toy that she's not interested in? Why does it matter? If an obsession gets to the point that the child is not doing school work or fails to do household chores, there might be an issue. But if she's 4 she's presumably not in school yet, so that's not an issue.
I'd say, just let it play out. Odds are she'll get over it eventually. And if not, so what? People who can single-mindedly pursue one thing for long periods of time tend to be very successful in life. She's better off than someone who flits constantly from one thing to another, and nothing can hold her interest for more than 5 minutes.