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Having spent months recording the monkeys’ calls in response to both natural and artificial stimuli, a group led by Klaus Zuberbühler of the University of St. Andrews in Scotland argues that the Campbell’s monkeys have a primitive form of syntax.

This is likely to be a controversial claim because despite extensive efforts to teach chimpanzees language, the subjects showed little or no ability to combine the sounds they learned into a sentence with a larger meaning. Syntax, basic to the structure of language, seemed be a uniquely human faculty.

“You have two humans, and they are taking part in some human ritual. They are sitting there silently at a table. They make no eye contact; they’re still, except every now and then one of them does nothing more taxing than lifting an arm and pushing a little piece of wood. And if it’s the right wood and the right chess grand masters in the middle of a tournament, they are going through 6,000 to 7,000 calories a day thinking, turning on a massive physiological stress response simply with thought and doing the same thing with their bodies as if they were some baboon who has just ripped open the stomach of their worst rival, and it’s all with thought, and memories and emotions. And suddenly we’re in the realm of taking just plain old nuts and bolts physiology and using it in ways that are unrecognizable.”

Worldwide, puberty is recognized by various cultures and celebrated as a rite of passage into adulthood. The methodical drumbeat of these religious and social ceremonies foreshadows the rhythm of reproduction that, in many ways, marks the final stage of development. Despite its social and physiological significance, including perpetuation of the species, the pathways that regulate the onset of puberty have evaded traditional physiological inquiries. No clear hormonal or metabolic trigger has been identified as a switch that activates the hypothalamic gonadotropin-releasing hormone (GnRH) pulse generator (1). Instead, geneticabnormalities that preclude puberty have provided the major insights into the pathways that are critical for the development and maturation of the reproductive axis (2, 3). Perhaps the best candidate for regulating the onset of puberty is kisspeptin, the ligand for the receptor encoded by GPR54, a gene identified as a cause of recessive hypogonadotropic hypogonadism (4, 5). The report by Pitteloud et al. (6) in this issue of PNAS identifies loss-of-function mutations in the prokineticin 2 (PROK2) gene, which encodes a secreted peptide that regulates the development and migration of the olfactory tract and GnRH neuron progenitors. The PROK2 mutations caused hypogonadotropic hypogonadism in both males and females. Using Prok2–/– knockout mice, the GnRH neuron progenitors were shown to cross the cribriform plate but fail to migrate into and populate the hypothalamus. Interestingly, olfactory tract development in humans with PROK2 mutations was variable, resulting in both nonanosmic and anosmic forms of hypogonadotropic hypogonadism. This report highlights the role of genetics as a means to unravel complex developmental processes and helps explain why anosmia is a frequent, but variable, feature of inherited forms of hypogonadotropic hypogonadism.

Communication about social topics is abundant in human societies, and many functions have been attributed to such gossiping. One of these proposed functions is the management of reputations. Reputation by itself has been shown to have a strong influence on cooperation dynamics in games of indirect reciprocity, and this notion helps to explain the observed high level of cooperation in humans. Here we designed a game to test a widespread assumption that gossip functions as a vector for the transmission of social information. This empirical study (with 14 groups of nine students each) focuses on the composition of gossip, information transfer by gossip, and the behavior based on gossip information. We show that gossip has a strong influence on the resulting behavior even when participants have access to the original information (i.e., direct observation) as well as gossip about the same information. Thus, it is evident that gossip has a strong manipulative potential. Furthermore, gossip about cooperative individuals is more positive than gossip about uncooperative individuals, gossip comments transmit social information successfully, and cooperation levels are higher when people encounter positive compared with negative gossip.