The ontogeny of fairness in seven societies.

A sense of fairness plays a critical role in supporting human cooperation. Adult norms of fair resource sharing vary widely across societies, suggesting that culture shapes the acquisition of fairness behaviour during childhood. Here we examine how fairness behaviour develops in children from seven diverse societies, testing children from 4 to 15 years of age (n = 866 pairs) in a standardized resource decision task. We measured two key aspects of fairness decisions: disadvantageous inequity aversion (peer receives more than self) and advantageous inequity aversion (self receives more than a peer). We show that disadvantageous inequity aversion emerged across all populations by middle childhood. By contrast, advantageous inequity aversion was more variable, emerging in three populations and only later in development. We discuss these findings in relation to questions about the universality and cultural specificity of human fairness.

Early understanding and production of graphic symbols.

Young children's ability to understand and produce graphic symbols within an environment of social communication was investigated in two experiments. Children aged 2, 3, and 4 years produced graphic symbols of simple objects on their own, used them in a social communicative game, and responded to experimenter's symbols. In Experiment 1 (N = 48), 2-year-olds did not effectively produce symbols or use the experimenter's symbols in the choice task, whereas 3- and 4-year-olds improved their drawings following the game and performed above chance with the experimenter's symbols. Ability to produce an effective graphic symbol was correlated with success on a task that measured understanding of the experimenter's symbols, supporting the claim that children's ability to produce a graphic symbol rests on the understanding of the symbolic function of pictures. In Experiment 2, 32 children aged 3 and 4 years improved their third set of drawings when they received feedback that their drawings were not effective communications. The results suggest that production and understanding of graphic symbols can be facilitated by the same social factors that improve verbal symbolic abilities, thereby raising the question of domain specificity in symbolic development.

Interference and dominance in texture segregation: hue, geometric form, and line orientation.

Five experiments were designed to test whether (1) lowering the similarity of elements within a region of texture (low-similarity arrays) would interfere with texture segregation, and (2) there would be dominance of one type of property difference over another in determining an observer's choice of boundary in two-boundary (ambiguous) displays. In Experiments 1 and 2, the interference question was assessed using stimuli formed from the dimensions hue and geometric form (circle/square or straight/curved novel shapes). The results indicated that when boundary judgments were based on form differences, segregation was significantly impaired by hue variation. However, hue segregations were not affected by form variation. In Experiments 3-5, the dominance question was examined using stimuli formed from hue and geometric form, as well as those formed from hue and line orientation (horizontal/vertical). Analyses revealed that there was no dominance of one type of property difference over another. Rather, observers' performance was completely predicted by the relative discriminabilities of the two boundaries. These findings support Beck's (1982) model of textural segmentation and call into question traditional notions of the preattentive stage of perceptual processing.