Caregivers around the world sing to their infants. Infants not only prefer to listen to infant-directed singing over adult-directed singing, but infant-directed singing also serves a function, communicating affective information to preverbal infants to aid in adjusting arousal levels. Pitch variation has previously been identified as one performance feature that may help to convey the message. Earlier research has indicated that infants' pitch preferences are context dependent, suggesting that infants are tuned in to the communicative intent of infant-directed singing. However, there are several other performance-based features present in infant-directed singing that may also contribute to the affective message. The current study examined the role of context on infants' tempo preferences in sung playsongs and lullabies. Using a head-turn preference procedure, we measured 24 preverbal infants' natural preferences for foreign language playsongs and lullabies as a function of tempo. Infants showed a preference for fast over slow tempo playsongs, but no such context dependent preference was found within lullabies. Results partially support the role of tempo as a communicative feature of infant directed singing.
Keywords: infant perception, music perception, tempo perception
Music is often used to express and elicit emotions (Juslin & Sloboda, 2001). Basic emotions such as happiness and sadness are easily attributed to musical pieces by both adult listeners (Cupchik, Rickert, & Mendelson, 1982) and young children (Trainor & Trehub, 1992). Clearly music has the potential to convey emotional information to listeners of various ages. The use of music as a means of emotional expression may be especially important to infant listeners. Caregivers' singing to their infants is a universal phenomenon (Brakeley, 1950; Trehub & Schellenberg, 1995), and infants demonstrate a clear attraction to maternal singing compared with maternal speech (Nakata & Trehub, 2004). Furthermore, infants show a preference for infant-directed singing compared with infant-absent singing (Trainor, 1996), and this preference is present in newborns (Masataka, 1999). One proposed function of infant-directed singing is to communicate affective information to preverbal infants to adjust their arousal levels (Trainor, 1996; Trehub & Schellenberg, 1995; Trehub, Trainor, & Unyk, 1993). However, the performance-based features of infantdirected singing that convey the message are unclear. While numerous studies have indicated that pitch is an informative performance based aspect of singing (Trainor, 1996; Trehub et al., 1993; Tsang & Conrad, 2010), other performance-based characteristics of infant-directed singing, such as rhythm and tempo, may also be informative to the infant. The present study addressed this issue by examining whether infants' preferences for tempo are contextdependent.
Infant-directed songs can generally be categorized into two major song types: playsongs and lullabies. Each song type has characteristic performance features. Playsongs are characterized by high rhythmicity, high pitch level, and fast tempo and are often employed by caregivers to arouse and stimulate their infant (Rock, Trainor, & Addison, 1999). In contrast, lullabies are often used to calm and soothe an infant to make them ready for sleep (Trehub & Trainor, 1998) and are typically sung at a lower pitch and slower tempo in comparison to playsongs. Trainor (1996) demonstrated that these performance features are perceptually discriminable to adult listeners, who were able to correctly categorize playsongs as playsongs and lullabies as lullabies. In addition, playsongs and lullabies elicit different behavioral responses from infants. Listening to playsongs often leads young infants to display outward behaviors and look to their caregivers more often, whereas listening to lullabies generally leads to infants directing their attention inward (Rock et al. …