Still Face Experiment: Dr. Edward Tronick. Note. Infant Social Development: 7 Ways to Encourage & Boost. Click here to go directly to 7 ways to encourage infant social development lower down on this page Interacting with other could be said to begin before a baby is even born. From about 18 weeks after conception a baby's hearing comes into action and he gradually becomes aware of the sounds of the world around him. His mother's heart beat of course, but other sounds too - voices and noises of home, the deeper voice of his father, the barking of a dog, shutting of doors and so on. Note.