Rakison and Yermolayeva (this issue) argue that domain specificity is difficult to reconcile with U-, N-, or M-shaped developmental trends. They are justified because: 1) There is no compelling evidence that nonlinear trends require mechanisms beyond general, well-known cognitive processes; and 2) epigenetic neuroscience provides no clear evidence of strong domain-specialized representations. Evidence implies pervasive weak (i.e., experience dependent) neural specialization for different kinds of information. © 2011 Taylor & Francis Group, LLC.

Flexible induction is the adaptation of probabilistic inferences to changing problems. Young children's flexibility was tested in a word-learning task. Children 3 to 6 years old were told 3 novel words for each of several novel objects. Children generalized each word to other objects with the same body shape, the same material, or the same part as the first object. Each word was preceded by a different predicate (i.e., "looks like a...," "is made of...," or "has a...") that implies a different attribute (shape, material, or part, respectively). Three-year-olds showed limited use of predicates to infer word meanings, and they used predicates from previous trials to infer the meanings of later words. Four- to 6-year-olds used predicate cues more consistently and made inferences that were implied by the most recent predicate cue. Notably, 3-year-olds performed near ceiling in a control task that eliminated the need to use probabilistic inductive cues (Experiment 3). The results suggest that flexibility develops as a function of (a) sensitivity to between-problem variability and indeterminacy and (b) ability to decontextualize the most recent verbal cue to guide of inductive inferences.

Our understanding of many mental, social and physical phenomena hinges on a general understanding that appearances can differ from reality. Yet young children sometimes seem unable to understand appearance-reality dissociations. In a standard test, children are shown a deceptive object and asked what it really is and what it looks like. Many preschool children give the same answer to both questions. This error has been attributed to children's inflexible conceptual representations or inflexibility in representing their own changing beliefs. However, evidence fails to support either hypothesis: new tests show that young children generally understand appearance-reality discrepancies as well as fantasy-reality distinctions. These tests instead implicate children's failure to understand the unfamiliar discourse format of the standard test. This misunderstanding might reveal a subtler difficulty in making logical inferences about questions.

Tool-use is specialized in humans, and juvenile humans show much more prolific and prodigious tool-use than other juvenile primates. Nonhuman primates possess many of the basic motor and behavioral capacities needed for manual tool-use: perceptual-motor specialization, sociocultural practices and interactions, and abstract conceptualization of kinds of functions, both real and imagined. These traits jointly contribute to the human specialization for tool-using. In particular, from 2 to 5 years of age children develop: (i) more refined motor routines for interacting with a variety of objects, (ii) a deeper understanding and awareness of the cultural context of object-use practices, and (iii) a cognitive facility to represent potential dynamic human-object interactions. The last trait, which has received little attention in recent years, is defined as the ability to form abstract (i.e., generalizable to novel contexts) representations of kinds of functions, even with relatively little training or instruction. This trait might depend not only on extensive tool-using experience but also on developing cognitive abilities, including a variety of cognitive flexibility: specifically, imagistic memory for event sequences incorporating causal inferences about mechanical effects. Final speculations point to a possible network of neural systems that might contribute to the cognitive capacity that includes sensorimotor, sensory integration, and prefrontal cortical resources and interconnections.

Our understanding of many mental, social and physical phenomena hinges on a general understanding that appearances can differ from reality. Yet young children sometimes seem unable to understand appearance–reality dissociations. In a standard test, children are shown a deceptive object and asked what it really is and what it looks like. Many preschool children give the same answer to both questions. This error has been attributed to children’s inflexible conceptual representations or inflexibility in representing their own changing beliefs. However, evidence fails to support either hypothesis: new tests show that young children generally understand appearance–reality discrepancies as well as fantasy–reality distinctions. These tests instead implicate children’s failure to understand the unfamiliar discourse format of the standard test. This misunderstanding might reveal a subtler difficulty in making logical inferences about questions.