The development of pointing perception in infancy: Effects of communicative signals on covert shifts of attention.

Abstract

The present study aims to investigate the interplay of verbal and nonverbal communication with respect to infants' perception of pointing gestures. Infants were presented with still images of pointing hands (cue) in combination with an acoustic stimulus. The communicative content of this acoustic stimulus was varied from being human and communicative to artificial. Saccadic reaction times (SRTs) from the cue to a peripheral target were measured as an indicator of the modulation of covert attention. A significant cueing effect (facilitated SRTs for congruent compared with incongruent trials) was only present in a condition with additional communicative and referential speech. In addition, the size of the cueing effect increased the more human and communicative the acoustic stimulus was. This indicates a beneficial effect of verbal communication on the perception of nonverbal communicative pointing gestures, emphasizing the important role of verbal communication in facilitating social understanding across domains. These findings additionally suggest that human and communicative (ostensive) signals are not qualitatively different from other less social signals but just quantitatively the most attention grabbing among a number of other signals.

The Development of Social Attention in Human Infants

“…Although these results converge with those reported by Rohlfing et al (2012) to suggest that infants orient in the direction of a pointing hand by 4 months of age, Daum et al (2013) suggest that infants do not orient in the direction of a pointing hand until 12 months of age. How can we reconcile these seemingly significant age differences?…”

“…It was sufficient for them to follow the direction of the point without any interpretation of its meaning. By contrast, infants in the Daum et al (2013) study were shown a pointing hand with an accompanying speech act. The combination of the two stimuli together may have resulted in infants interpreting the stimulus not as a directional cue, per se, but rather as a communicative act requiring that infants understand the referential intention of the pointing hand (i.e., infants appreciate that the hand is attached to a social partner who is directing their attention to a specific referent).…”

“…Most studies, however, still rely on presenting highly scripted and repetitive actions to infants in experimental paradigms involving a digital image, or movie, of a social partner looking or reaching toward an object following an ostensive cue, such as eye contact with the viewer (e.g., Daum et al, 2013). Frank and colleagues (Frank, Vul, & Johnson, 2009;Frank, Vul, & Saxe, 2012) have made some important progress in studying infants' and toddlers' social attention to more naturalistic visual scenes.…”

“…One reason for the sparseness of relevant findings is that most studies obviate the need for infants choosing between different stimulus cues. As previously discussed, infants are typically presented with a specific sequence of events, such as an actor eliciting an infant's attention, and then looking or pointing in a specific direction followed by an object appearing in either that direction or the opposite direction; infants merely have to attend to the stimuli in the order they appear and not choose when, and what, to look at (e.g., Bertenthal et al, 2014;Daum et al, 2013). In more naturalistic situations, such as an infant interacting with a caregiver in a cluttered room among a set of objects over a more extended period of time, the caregiver might alternate between gazing at the child and the objects, and jointly playing with those objects or showing them to the child.…”

Productive Verbs Facilitate Action Prediction in Toddlers

“…These results were 302 GAMPE & DAUM extended by a further condition in which infants at the age of 10 months heard two labels that were unrelated to the visual category. The presence or absence of communicative speech has a substantial influence on infants' performance in an A-not-B error task at the age of 10 months (Top al, Gergely, Mikl osi, Erd€ ohegyi, & Csibra, 2008) and on the perception of pointing gestures at the age of 12 months (Daum, Ulber, & Gredeb€ ack, 2013). And even beyond the preverbal months, language can influence the way we perceive objects.…”