![Researchers say the quality of adult-child interactions is key.](https://centerforhealthjournalism.org/sites/default/files/styles/teaser_list_thumbnail_large/public/title_images/4420896678_841afe2800_o.jpg?itok=hH2Fs0_x)
One of the recurring themes in early childhood research is that early is rarely early enough. Positive back-and-forth interactions between kids and caregivers are key to building budding brains, while their absence can lead to kids who suffer the longterm effects of what experts call "toxic stress."