Effects of Different Types of Contingent Tactile Stimulation on Crying, Smiling, and Sleep in Newborns: An Observational Study ABSTRACT: Sleep, the brain and the ability to interact with the environment change a great deal over the first year of life; however, there are no studies on the possible influence of different environmental stimulations on the organization of subsequent sleep–wake cycles in infants. The hypothesis of this study was that greater continuity of contingent tactile stimulation decreases crying behavior, subsequent active sleep (AS) and its fragmentation, and increases smiling behav- ior and subsequent quiet sleep in newborns. Forty out of the 82 newborns (15- to 30-hr old) of the initial sample satisfied the inclusion criteria and completed the first cycle of sleep during the period between two feedings. The 40 newborns were randomly assigned to four groups after 2 0 of baseline observation: continu- ous stimulation (CS, n ¼ 10); discontinuous nonperiodic stimulation (DnPS, n ¼ 10); discontinuous periodic stimulation (DPS, n ¼ 10); absent stimulation (AbS, n ¼ 10). During baseline measurements, there were no significant differ- ences in crying and smiling behaviors between the four groups, while during the subsequent stimulated wake, the CS group compared to the DnPS group showed more smiling (p < .05) and less crying (p < .05), longer poststimulation wake before sleep (p < .01) as well as AS with a lower percentage of grouped-rapid eye movements [grouped REM (GREM); p < .001]. The number of GREM during AS was negatively correlated to the number of smiles (p < .05) and posi- tively to the number of cries (p < .05) of the previous stimulated wake. These findings suggest that, after birth, different continuity levels of contingent tactile stimulations may affect crying and smiling behaviors and the organization of behavioral states. AS could have an important role in processing affective states. ß 2012 Wiley Periodicals, Inc. Dev Psychobiol 55: 508–517, 2013. Keywords: newborns; active sleep; contingent tactile stimulation; behavioral states; crying; smiling INTRODUCTION Newborn life is organized into behavioral states (Thoman, 1990; Wolff, 1987). Behavioral states are a means of interacting with the environment, and are influenced by and in turn influence the environment. Maturation of sleep/wake patterns is one of the most important physiological developments during the first year of life (Sheldon, 1996). Despite the fact that cen- tral nervous system (CNS) development continues throughout life, the most evident changes occur during the first 2 years (Kinney, Brody, Kloman, & Gilles, 1988). An essential process involved in brain maturation is brain plasticity, which is the ability of the infant brain to change its structure and function in response to the environment (Graven, 2006). In young animals deprived of rapid eye movements (REM) and non- REM sleep, brain plasticity decreases with negative Developmental Psychobiology Marco Cecchini 1 Eleonora Baroni 1 Cinzia Di Vito 1 Federica Piccolo 1 Paola Aceto 2 Carlo Lai 1 1 Department of Dynamic and Clinical Psychology, Sapienza University of Rome Via degli Apuli 1, 00185 Rome, Italy E-mail: carlo.lai@uniroma1.it 2 Department of Anesthesiology and Intensive Care, Catholic University of Sacred Heart, Rome, Italy Manuscript Received: 2 September 2011 Manuscript Accepted: 9 May 2012 Correspondence to: C. Lai Article first published online in Wiley Online Library (wileyonlinelibrary.com): 1 June 2012 DOI 10.1002/dev.21054  ß 2012 Wiley Periodicals, Inc.