Investigating motionese: The effect of infant-directed action on infants’ attention and object exploration

Abstract

Adults modify their communication when interacting with infants, and these modifications have been tied to infant attention. However, the effect infant-directed action on infant behavior is understudied. This study examined whether infant-directed action affects infants, specifically their attention to and exploratory behaviors with objects. Forty-eight 8- to 10-month-old infants and their caregivers participated in a laboratory session during which caregivers demonstrated objects to infants using infant-directed action. Results indicated that variation in amplitude and repetition were tied to differences in infant attention, and varying levels of repetition were tied to differences in object exploration.

Introduction

In many cultures around the world (though not all; Ochs and Schieffelin, 1995, Pye, 1992), adults and older children speak to infants differently than they do to peers (Newport, 1977). Specifically, speech to infants is characterized by high pitch, short utterance length, exaggerated intonation contours, content simplification, and limitation to shared experiences (e.g., Snow, 1991, Stern et al., 1982).

Infant-directed communication has also been described in the manual modality. Signs used with infants by signing caregivers are typically slow and involve high levels of repetition and exaggerated movements (Masataka, 1992). These characteristics are strikingly similar to those observed in infant-directed speech and it suggests that infant-directed communication is not modality specific (Masataka, 1996).

In addition to speech and sign, caregivers also modify the gestures they produce with infants. Iverson, Capirci, Longobardi, and Caselli (1999) found that when mothers were interacting with infants, relative to other adults, they used gestures less frequently, and when gestures were used, they were more likely to co-occur with speech and to reinforce rather than supplement the content expressed in speech.

Numerous studies also indicate that caregiver modifications of this sort influence infants’ attention to the communicative input. For example, as early as 1 month of age, infants prefer infant-directed to adult-directed speech (e.g., Cooper et al., 1997, Fernald, 1985); and infants’ attention to a visual display is enhanced in the presence of infant-directed vs. adult-directed speech (Werker, Pegg, & McLeod, 1994). Similar results have been obtained for sign language, with longer times accruing for infant-directed relative to adult-directed signs, both for deaf infants and for hearing infants with no previous exposure to sign language (Masataka, 1996, Masataka, 1998). While the specific features of infant-directed communication that capture infants’ attention have yet to be identified, there is general agreement that the exaggerated properties of infant-directed speech (e.g., wide pitch variations) and sign (e.g., slow, large, repeated movements) are maximally likely to capture infants’ attention (e.g., Masataka, 1996, Masataka, 1998).

Recently, evidence for caregiver modification has been provided for a new domain: infant-directed action. Brand, Baldwin, and Ashburn (2002) investigated the properties of actions produced by 51 caregivers engaged in communication with either their own infant or a familiar adult. Caregivers were given five novel objects with instructions describing how each worked. They were then asked to interact with their partner (infant or adult) with each of these objects.

Results indicated that caregivers modified object-related actions when interacting with infants. The authors termed these modified actions “motionese” and identified six action parameters that differed significantly when the communicative partner was an infant. Relative to adult-directed action, infant-directed action occurred in closer proximity to the partner, involved higher interactiveness, more enthusiasm and more repetition, was simpler, and had increased amplitude of movement.

In interpreting their results, Brand et al., 2002, Brand et al., 2007 have speculated that motionese may enhance infants’ attention to action and help infants understand structure in action. Brand and Shallcross (2008) addressed this possibility in a study of infants’ visual preferences for infant-directed vs. adult-directed action. Their results indicated that both 6–8 and 11–13-month-old infants prefer infant-directed to adult-directed action, even when faces were obscured. While these results highlight infants’ visual preference for infant-directed action, it is unclear whether the individual parameters of motionese play varying roles in infant attention.

Motionese may also influence infants in other ways. Adults’ object-related actions with infants are just that, object-related. It stands to reason, therefore, that motionese may also influence infant attention to the objects upon which the caregiver is acting. Infants might attend longer to objects presented via motionese and/or they might be more likely to attend to certain object properties rather than to others. Since object properties are known to impact infants’ manipulation of objects (e.g., Lockman and McHale, 1989, Ruff, 1984), variations in infant attention to objects as a function of caregivers’ manipulation of the objects in the context of motionese may also influence infants’ subsequent object manipulation.

While infant preference for motionese to adult-directed action has been documented (Brand & Shallcross, 2008), the role of individual parameters of motionese on infant attention is unclear. Further, no published work has addressed the role of infant-directed action in infants’ object exploration. Therefore, the goals of the present study are twofold: (a) to examine infant attention to motionese and explore whether attention varies in relation to the number of action parameters modified; and (b) to assess the impact of motionese on infants’ subsequent exploration of objects manipulated by caregivers in the context of motionese displays. In the present study, infants viewed a set of objects manipulated by caregivers with simple actions containing enhanced or low amplitude and/or repetition. Looking to these displays was compared to looking in trials in which objects were held still in front of the infants. Infants’ subsequent exploration and manipulation of objects following motionese displays was coded to determine whether variations in aspects of motionese influenced ways in which infants engaged with the objects.