Has there been much work or study done in the area of interactive design for children of pre-school age? There seems to be a number of apps used in childcare centres that are meant to facilitate learning with a child educator, so I am interested to find out the type of research and design guidelines available for this particular user group.
Pediatricians are not too keen on mobile use by children under 30 months of age. Radesky, Schumacher and Zuckerman, Mobile and Interactive Media Use by Young Children: The Good, the Bad, and the Unknown, Pediatrics 2015 135:1. But mobile use by children is not going to stop just because it's not as good as in-person interaction. And there are documented cases where app use can be very helpful, especially for special populations like hearing impaired, autistic or hospitalized children who must take neurological assessments on a handheld device.
Here is an interesting article in UX Mag by Jonathan Evans with useful and specific usability guidelines that are age-appropriate, pulled from Debra Gelman's book, Design for Kids.
There have also been several studies on instructional design for very specific cases. Apps to promote physical activity, apps to help kids acquire language, apps that help dyslexic kids write more effectively are some examples. The research that I read focused on using technology to gamify and reward real-world behaviors, provide extra practice in skills acquisition, or use games to teach or enhance concepts.
None of these studies go beyond basic usability and instructional design (just adapted for children) to present a set of standards specifically for children the way Debra Gelman's book does.