There have been numerous studies which have discovered that infants who are left to cry unattended and have restricted physical contact have been found to have higher levels of stress hormones such as cortisol as opposed to infants whose needs are rapidly tended to and experience regular, close physical contact and interaction with their parents:
Dr. Wayne Brake, a University of California neurodevelopment professor and researcher states: 'That whenever babies are deprived of comfort or placed in a chaotic environment, the resulting stress causes the release of cortisol and other hormones, altering metabolism. This affects the growth and development of the baby’s brain. Research suggests that infants who are left alone to cry in the crib have poorer overall health outcomes than babies who are consistently picked up. All parents should think twice before routinely leaving a vulnerable infant with a non-attached person, or leaving it to cry alone in the crib for prolonged periods for "training" purposes. These practices cause permanent changes to the brain’s dopamine and seratonin systems, rendering the person more susceptible to addiction, alcoholism and depression in adulthood. Most parents instinctively know this to be true, but they’ve simply had their parenting instincts smothered over with poor advice' .
This is ultra important research that the shows producers should have done prior to letting that awful woman loose on defenceless infants on TV. The parents should be informed of the medical research in this area then take Claire Verity and the shows producers to task in court!, a law should be passed to ban such harsh and outdated parenting methods.

90% of what we know about the human brain has been discovered in the last 15 years (and since these baby books were written). Maintenance of critical levels of tactile input is important for normal brain maturation (Shore). A mother precisely controls every element of her infant's physiology from its heartbeat to its release of hormones, from its appetite to the intensity of its activity (Gallagher). Clearly she can't do this if she doesn't touch her baby! The babies who are left to cry are exhibiting a universal response to separation from mother and that is despair - they shut down for prolonged survival. Early interpersonal events positively and negatively impact the structural organisation of the brain. Early separation is harmful and can produce major shifts in susceptibility to stress induced pathology (Hofer) Verity read the neuroscience that is now available and leave babies to their mothers!