“…Sibling relationships have the potential to provide young children with some of their earliest experiences of intense positive (e.g., joy, excitement) and negative (e.g., frustration, anger, jealousy) emotions (Kramer, 2014 ; Lindsey, 2020 ). Furthermore, there is evidence that the quality of sibling relationships is a unique predictor of children’s psychosocial outcomes, beyond the contributions of caregiver–child relationships (McHale, Updegraff, et al, 2012 ; McHale, Waller, et al, 2012 ; Modry-Mandell et al, 2007 ; Stormshak et al, 2009 ; Whiteman et al, 2020 ). Sibling interactions may provide opportunities for children to observe their siblings model adaptive emotion regulation skills or to benefit from siblings who provide them with coregulation during moments of distress (Kramer, 2014 ).…”