“…Specifically, negative or difficult infant temperament has been associated with shorter sleep duration, particularly at night (Loutzenhiser & Sevigny, 2008; Weissbluth, 1981), and more night wakings (Weinraub et al, 2012) compared to positive or easy infant temperament, which has conversely been associated with greater night and total sleep duration (Kaley et al, 2012; Spruyt et al, 2008). In contrast, some studies report weak or no associations between temperament and sleep (e.g., Anders et al, 1992; DeLeon & Karraker, 2007; Scher, Tirosh, & Lavie, 1998), which may be the result of age-dependent changes in this relation (Spruyt et al, 2008; Weinraub et al, 2012), or temperament’s differential relation with active compared to quiet sleep (Parslow et al, 2002).…”