Coordinated affect with mothers and strangers: A longitudinal analysis of joint engagement between 5 and 9 months of age

The coordination of affect in joint attention was assessed in a longitudinal study of 5- to 9-month-old infants as they interacted with mothers and strangers. Results showed that the coordination of affect with joint attention looks increased reliably with age. In addition, context effects were found such that joint attention looks increased while interacting with strangers but not with mothers. The study demonstrates the emergence of joint engagement before the end of the first year, and suggests that affect may play a key role in aspects of joint attention that may be unique to humans.     

Language Signaling High Proportions and Generics Lead to Generalizing,but Not Essentializing,for Novel Social Kinds

Generics (e.g., “Dogs bark”) are thought by many to lead to essentializing: to assuming that members of the same category share an internal property that causally grounds shared behaviors and traits, even without evidence of such a shared property. Similarly, generics are thought to increase generalizing, that is, attributing properties to other members of the same group given evidence that some members of the group have the property. However, it is not clear from past research what underlies the capacity of generic language to increase essentializing and generalizing. Is it specific to generics, or are there broader mechanisms at work, such as the fact that generics are terms that signal high proportions? Study 1 (100 5–6 year-olds, 140 adults) found that neither generics, nor high-proportion quantifiers (“most,” “many”) elicited essentializing about a novel social kind (Zarpies). However, both generics and high-proportion quantifiers led adults and, to a lesser extent, children, to generalize, with high-proportion quantifiers doing so more than generics for adults. Specifics (“this”) did not protect against either essentializing or generalizing when compared to the quantifier “some.” Study 2 (100 5–6 year-olds, 112 adults) found that neither generics nor visual imagery signaling high proportions led to essentializing. While generics increased generalizing compared to specifics and visual imagery signaling both low and high proportions for adults, there was no difference in generalizing for children. Our findings suggest high-proportion quantifiers, including generics, lead adults, and to some extent children, to generalize, but not essentialize, about novel social kinds.