The benefits of shared reading according to neuroscience
Innumerable studies have shown that shared reading between a child and an adult has many important benefits for children. Shared reading causes the firing of an immense number of neurons, creating new circuits and strengthening existing ones.
Studies have found that children who are exposed to strong reading environments at home develop larger neural circuits that support narrative comprehension. This process facilitates learning to read and write.  Shared reading is a clear case of biological embedding, a process in which the brain undergoes long-term physical changes in response to cognitive stimulation during early childhood.
Shared reading is so influential for the child that even modest increases of the activity are associated with improved brain function in the areas supporting literacy. The more engaged the child is during shared reading, the better, faster, and stronger the connections between neurons become. 
Children that are encouraged to engage with the adult reader in the form of questions and exchange of opinions can form stronger social-emotional connections between stories and their own life. In addition to all other benefits, sharing the reading experience with others increases the pleasure we gain from a story.