half of Snoo users opt to rent the device from Happiest Baby at a cost of around $150 a month. Criticism Efficacy of the calming technique Ralph Frenken has argued against Karp's recommendation of the use of tight swaddling and the concept of a "calming reflex." The criticism is that the effect of swaddling is not based on reflexes because (1) a releasing stimulus is missing, because swaddling most probably works by the decrease of proprioceptive and tactile stimulation and (2) the reflex response is missing, because any reflex always consists of a movement released by muscles. The child does not move but falls asleep by swaddling. Additionally, no known reflex alters the state of consciousness, but swaddling obviously does. Lactation and breastfeeding expert Nancy Mohrbacher collected several scientific studies which demonstrated negative aspects of swaddling on newborn infants. In 2010, researchers studied the effects of video instruction concerning swaddling, side positioning, white noise, jiggling, and sucking on parents' ability to calm fussing babies. The results against a control group were statistically insignificant compared to traditional methods. Use of celebrity endorsements CBS news reports that "Critics say Karp is riding to fame on the strength of his patients' VIP parents, who include Michelle Pfeiffer, Pierce Brosnan and Madonna. Endorsements from several stars appear on his book jacket and video cover." Prohibitive cost of the Snoo Part of the appeal of Karp’s methods for calming babies was that it didn't require any fancy or expensive equipment beyond a blanket. A New York Times article cites that his messaging changed with the creation of the Snoo toward spending money on the device, "Now he was suggesting that, actually, the best way to improve your baby’s sleep required splurging on a sensory bed." A Washington Post article declare the device as the touchstone for privilege due to its prohibitive cost for many parents and that the product "has a way of separating even well-to-do parents into the Snoos and the Snoo-nots." Addressing the criticism of the device's cost, Karp downplayed the expense stating that the device gives parents a “24-hour caregiver for the cost of 16 cents an hour.” The high cost of the Snoo has also led to scams in the secondhand market where thieves rent the device on a stolen credit card and resell it to unwitting parents before the company remotely disabled the device. References American pediatricians American family and