We investigated the influence of speaker certainty on 156 four-year-old children's sensitivity to generic and nongeneric statements. An inductive inference task was implemented, in which a speaker described a nonobvious property of a novel creature using either a generic or a nongeneric statement. The speaker appeared to be confident, neutral, or uncertain about the information being relayed. Preschoolers were subsequently asked if a second exemplar shared the same property as the first. Preschoolers consistently extended properties to additional exemplars only when properties were described in a generic form by a confident or neutral speaker. If a speaker appeared to be uncertain or if statements were made in a nongeneric form, properties were not consistently extended beyond the first exemplar. The findings demonstrate that children integrate the inductive cues provided by generic language with social cues when reasoning about abstract kinds. (Contains 1 figure and 2 tables.)