In over-imitation, children copy even elements of a goal-directed action sequence that appear unnecessary for achieving the goal. We demonstrate in 4-year olds that the unnecessary action is specifically associated with the goal, not generally associated with the apparatus. The unnecessary action is performed flexibly: 4-year olds usually omit it if it has already been performed by an adult. Most 5-year olds do not verbally report the unnecessary action as necessary when achieving the goal, although most of them report an equivalent but necessary action as necessary. Most 5-year olds explain the necessary action in functional terms, but are unsure as to the function of the unnecessary action. These verbal measures do not support the hypothesis that children over-imitate primarily because they encode unnecessary actions as causing the goal even in causally transparent systems. In a causally transparent system, explanations for over-imitation fitting the results are that children are ignorant of the unnecessary action's purpose, and that they learn a prescriptive norm that it should be carried out. In causally opaque systems, however, for children and for adults, any action performed before achieving the goal is likely to be inferred as causally necessary-this is not over-imitation, but ordinary causal learning.

Children aged 3 years and 4½ years old watched a puppet, struggling to achieve goals, who was helped by a 2nd puppet and violently hindered by a 3rd. The children then distributed wooden biscuits between the helper and hinderer. In Experiment 1, when distributing a small odd number of biscuits, 4½-year-olds (N = 16) almost always gave more to the helper. Children verbally justified their unequal distributions by reference to the helper's prosocial behavior or the hinderer's antisocial behavior. In Experiment 2, when biscuits were more plentiful, 4½-year-olds (N = 16) usually gave equal numbers to helper and hinderer, indicating that 4½-year-olds usually preferred not to distribute unequally unless forced to by resource scarcity. Three-year-olds (N = 16 in Experiment 1, N = 20 in Experiment 3) gave more biscuits equally often to the helper and to the hinderer. In many cases, this was because they were confused as to the identities and actions of the puppets, possibly because they were shocked by the hinderer's actions. Two fundamental moral behaviors are therefore demonstrated in young preschoolers: indirect reciprocity of morally valenced acts and a preference for equality when distributing resources, although the cognitive bases for these behaviors remain unclear. These results join other recent studies in demonstrating that the seeds of complex moral understanding and behavior are found early in development.

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New Caledonian crows (Corvus moneduloides) are the most prolific avian tool-users. Regional variation in the shape of their tools may be the result of cumulative cultural evolution--a phenomenon considered to be a hallmark of human culture. Here we show that hand-raised juvenile New Caledonian crows spontaneously manufacture and use tools, without any contact with adults of their species or any prior demonstration by humans. Our finding is a crucial step towards producing informed models of cultural transmission in this species, and in animals in general.

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We presented infants (5, 6, 9, and 12 months old) with movies in which a female model turned toward and fixated 1 of 2 toys placed on a table. Infants' gaze was measured using a Tobii 1750 eye tracker. Six‐, 9‐, and 12‐month‐olds' first gaze shift from the model's face (after the model started turning) was directed to the attended toy. The 5‐month‐olds performed at random. Following this initial response, 5‐, 6‐, and 9‐month‐olds performed more gaze shifts to the attended target; 12‐month‐olds performed at random. Infants at all ages displayed longer looking times to the attended toy. We discuss a number of explanations for 5‐month‐olds' ability to follow a shift in overt attention by an adult after an initially random response, including the possibility that infants' initial gaze response strengthens the representation of the objects in the peripheral visual field.

New Caledonian Crows Corvus moneduloides are known to be extraordinary tool makers and users, but little is known of other aspects of their biology. Here, we report recent field observations of their behaviour and ecology, along with measurements of 19 morphological traits and two flight performance parameters taken from 22 captured Crows. These measurements showed that the Crows were sexually dimorphic in size (the males were larger) but not in shape. We also found that the crows lived in mixed‐sex groups, and we observed juvenile‐type begging behaviour and feeding by regurgitation, which supports the hypothesis that these may be family groups.

The term goal directed conventionally refers to either of 2 separate process types-motor processes organizing action oriented toward physical targets and decision-making processes that select these targets by integrating desire for and knowledge of action outcomes. Even newborns are goal directed in the first sense, but the status of infants as decision makers (the focus here) is unknown. In this study, 24-montholds learned to retrieve an object from a box by pressing a button, and then the object's value was increased. After the object's subsequent disappearance, these children were more likely to press the button to try to retrieve the object than were control 24-month-olds who had learned to retrieve the object but for whom the object's value was unchanged. Such sensitivity to outcome value when selecting actions is a hallmark of decision making. However, 14-and 19-month-olds showed no such sensitivity. Possible explanations include that they had not learned the specifics of the action outcome; they had not acquired the necessary desire; or they had acquired both but did not integrate them to make a decision.