2018 Sat Poster 6340

Saturday, November 3, 2018 | Poster Session II, Metcalf Small | 3:15pm

A language-specific processing system supports infants’ language-cognition link
D. Perszyk, S. Waxman

Human language derives its power from its links to cognition. Recent work has demonstrated that infants establish this link by 3-4 months of age (Ferry, Hespos, & Waxman, 2010): human and nonhuman primate vocalizations, but not tone sequences or backward speech, support infants’ object categorization, a core conceptual capacity (Ferry et al., 2010; Ferry, Hespos, & Waxman, 2013). These results provide insights into the developmental and evolutionary foundations for human language. However, they leave a vital question unanswered: is infants’ precocious link between communicative signals and cognition guided by a single system—one that operates on both nonhuman primate vocalizations and human language? Or might this link be guided by two systems—one that is generalized for primate vocalizations and the other that is specialized for human language (Ackermann, Hage, & Ziegler, 2014; Owren, Amoss, & Rendall, 2011)?

If the same processing system supports infants’ links between all primate vocalizations (including human languages) and cognition, then all human languages should exert the same advantageous effect on object categorization at 3 and 4 months. In contrast, if two different processing systems support infants’ links between communicative signals and cognition—a dedicated speech processing system for human language and a primate-general system for nonhuman primate vocalizations—then it is possible that all human languages do not exert the same advantageous effect on object categorization at this young age, because infants are already tuning to their native language by 3 months.

To adjudicate between these alternatives we designed two experiments with English- acquiring infants at 3-4 months (Fig. 1), when infants are already well-tuned to the rhythmic class of their native language (Moon, Cooper, & Fifer, 1993; Nazzi, Bertoncini, & Mehler, 1998) but not yet tuned to its phonemic repertoire (Kuhl et al., 2006; Kuhl, Williams, Lacerda, Stevens, & Lindblom, 1992; Werker & Tees, 1984). Experiment 1 tested whether listening to German, a non-native language from the same rhythmic class as English, supports infants’ object categorization. Infants listening to German successfully formed the object categories (M = .59, SD = .13; t(30) = 3.7, p < .001). Experiment 2 tested whether listening to Cantonese, a non- native language from a different rhythmic class than English, supports infants’ object categorization. In contrast to infants listening to English (Ferry et al., 2010), nonhuman primate vocalizations (Ferry et al., 2013), or German (Experiment 1), infants listening to Cantonese failed to form the object categories (M = .51, SD = .15; t(37) = .38, p = .71).

These results (Fig. 2) reveal that infants use their native language as an “anchor” in establishing the foundational link between language and cognition. They also suggest that the language-cognition link, as it initially emerges in development, is different than the links between other communicative signals and cognition—links that infants eventually sever. This developmental evidence suggests an intriguing evolutionary possibility: the phylogenetic origins of the uniquely human language-cognition link may have been founded in our ancestors’ increasing perceptual-motor expertise with progressively more precise and nuanced human vocalizations (Ackermann et al., 2014).

References

Ackermann, H., Hage, S. R., & Ziegler, W. (2014). Brain mechanisms of acoustic communication in humans and nonhuman primates: an evolutionary perspective. Behavioral and Brain Sciences, 37, 529–604. http://doi.org/10.1017/S0140525X13003099

Ferry, A. L., Hespos, S. J., & Waxman, S. R. (2010). Categorization in 3- and 4-month-old infants: An advantage of words over tones. Child Development, 81(2), 472–9. http://doi.org/10.1111/j.1467-8624.2009.01408.x

Ferry, A. L., Hespos, S. J., & Waxman, S. R. (2013). Nonhuman primate vocalizations support categorization in very young human infants. Proceedings of the National Academy of Sciences of the United States of America, 110(38), 15231–35. http://doi.org/10.1073/pnas.1221166110

Kuhl, P. K., Stevens, E., Hayashi, A., Deguchi, T., Kiritani, S., & Iverson, P. (2006). Infants show a facilitation effect for native language phonetic perception between 6 and 12 months. Developmental Science, 9(2), F13–F21.

Kuhl, P. K., Williams, K. A., Lacerda, F., Stevens, K. N., & Lindblom, B. (1992). Linguistic experience alters phonetic perception in infants by 6 months of age. Science, 255, 606–608.

Moon, C., Cooper, R. P., & Fifer, W. P. (1993). Two-day-olds prefer their native language.

Infant Behavior and Development, 16(4), 495–500. http://doi.org/10.1016/0163- 6383(93)80007-U

Nazzi, T., Bertoncini, J., & Mehler, J. (1998). Language discrimination by newborns: toward an understanding of the role of rhythm. Journal of Experimental Psychology. Human Perception and Performance, 24(3), 756–66.

Owren, M. J., Amoss, R. T., & Rendall, D. (2011). Two organizing principles of vocal production: Implications for nonhuman and human primates. American Journal of Primatology, 73(6), 530–44. http://doi.org/10.1002/ajp.20913

Werker, J. F., & Tees, R. C. (1984). Cross-language speech perception: Evidence for perceptual reorganization during the first year of life. Infant Behavior and Development, 7, 49–63.