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Humans closely monitor others' cooperative relationships [1, 2]. Children and adults willingly incur costs to reward helpers and punish non-helpers-even as bystanders [3-5]. Already by 3 months, infants favor individuals that they observe helping others [6-8]. This early-emerging prosocial preference may be a derived motivation that accounts for many human forms of cooperation that occur beyond...

Infants' early gaze alternations are one of their first steps towards a sophisticated understanding of the social world. This ability, to gaze alternate between an object of interest and another individual also attending to that object, has been considered foundational to the development of many complex social-cognitive abilities, such as theory of mind and language. However, to understand the ...

Although both bonobos and chimpanzees are male-philopatric species, outcomes of male-male reproductive competition seem to be more closely associated with mating success in chimpanzees. This suggests that the extent of male reproductive skew is lower in bonobos. In addition, between-group male-male reproductive competition is more lethal in chimpanzees. This suggests that between-group differen...

limited information is available on water and nitrogen (n) management of sugarcane (saccharum officinarum l.) in khuzestan, southwestern iran, where this crop is currently and extensively grown under heavy irrigation and n fertilization. therefore, a field experiment was conducted from september 2000 to march 2002 at the research department of karoon agro-industry in khuzestan to determine the ...