Connecting primate gesture to the evolutionary roots of language: A systematic review.

Comparative psychology provides important contributions to our understanding of the origins of human language. The presence of common features in human and nonhuman primate communication can be used to suggest the evolutionary trajectories of potential precursors to language. However, to do so effectively, our findings must be comparable across diverse species. This systematic review describes the current landscape of data available from studies of gestural communication in human and nonhuman primates that make an explicit connection to language evolution. We found a similar number of studies on human and nonhuman primates, but that very few studies included data from more than one species. As a result, evolutionary inferences remain restricted to comparison across studies. We identify areas of focus, bias, and apparent gaps within the field. Different domains have been studied in human and nonhuman primates, with relatively few nonhuman primate studies of ontogeny and relatively few human studies of gesture form. Diversity in focus, methods, and socio-ecological context fill important gaps and provide nuanced understanding, but only where the source of any difference between studies is transparent. Many studies provide some definition for their use of gesture; but definitions of gesture, and in particular, criteria for intentional use, are absent in the majority of human studies. We find systematic differences between human and nonhuman primate studies in the research scope, incorporation of other modalities, research setting, and study design. We highlight eight particular areas in a call to action through which we can strengthen our ability to investigate gestural communication's contribution within the evolutionary roots of human language.

A narrative synthesis of research evidence for tinnitus-related complaints as reported by patients and their significant others.

BACKGROUND: There are a large number of assessment tools for tinnitus, with little consensus on what it is important to measure and no preference for a minimum reporting standard. The item content of tinnitus assessment tools should seek to capture relevant impacts of tinnitus on everyday life, but no-one has yet synthesised information about the range of tinnitus complaints. This review is thus the first comprehensive and authoritative collection and synthesis of what adults with tinnitus and their significant others report as problems in their everyday lives caused by tinnitus. METHODS: Electronic searches were conducted in PubMed, Embase, CINAHL, as well as grey literature sources to identify publications from January 1980 to June 2015 in which participants were enrolled because tinnitus was their primary complaint. A manual search of seven relevant journals updated the search to December 2017. Of the 3699 titles identified overall, 84 records (reporting 86 studies) met our inclusion criteria and were taken through to data collection. Coders collated generic and tinnitus-specific complaints reported by people with tinnitus. All relevant data items were then analyzed using an iterative approach to narrative synthesis to form domain groupings representing complaints of tinnitus, which were compared patients and significant others. RESULTS: From the 86 studies analyzed using data collected from 16,381 patients, 42 discrete complaints were identified spanning physical and psychological health, quality of life and negative attributes of the tinnitus sound. This diversity was not captured by any individual study alone. There was good convergence between complaints collected using open- and closed-format questions, with the exception of general moods and perceptual attributes of tinnitus (location, loudness, pitch and unpleasantness); reported only using closed questions. Just two studies addressed data from the perspective of significant others (n = 79), but there was substantial correspondence with the patient framework, especially regarding relationships and social life. CONCLUSIONS: Our findings contribute fundamental new knowledge and a unique resource that enables investigators to appreciate the broad impacts of tinnitus on an individual. Our findings can also be used to guide questions during diagnostic assessment, to evaluate existing tinnitus-specific HR-QoL questionnaires and develop new ones, where necessary. TRIAL REGISTRATION: PROSPERO registration number: CRD42015020629 . Protocol published in BMJ Open. 2016;6e009171.

Exploring greetings and leave-takings: communication during arrivals and departures by chimpanzees of the Bossou community, Guinea.

In human fission-fusion societies, ritualized non-linguistic signal exchanges that include gestures, vocalizations, and facial expressions are regularly observed at both arrivals (greetings) and departures (leave-takings). These communicative events play an important role in the formation and maintenance of social relationships. Wild chimpanzees also form large communities that split into smaller fluid parties during daily activities, with individuals moving freely between them. However, in chimpanzees only greetings have been reported. This study explores signal exchanges in the Bossou chimpanzee community during fissions (departures) and fusions (arrivals) given an individual's social rank, kinship, position as traveller or party-member, the level of potential threat, and the party size and presence of mature males. We analysed three time periods (1993-1994; 2003-2004; 2013-2014) during which the composition and social hierarchy of the community varied. We show that the occurrence and form of communication during fission and fusion events are mediated by social factors, including rank, kinship, and party size and composition. Individuals were more likely to communicate during fusions than during fissions, communication was more likely to be produced towards a higher-ranking individual and to non-kin individuals, but the tendency to communicate in general increased with an increase in social rank. The presence of more individuals, and in particular mature males, decreased the likelihood of communication. Communication during fusions supported patterns reported in previous studies on greetings, and our results support the argument that, if present, leave-takings are not a common feature of chimpanzee social interactions. Current methodological difficulties regarding the function of declarative signals hinder our ability to discriminate potential parting rituals within communication before departures. Given similar methodological difficulties, we also provide a note of caution in the interpretation of all signals produced during fusions as 'greetings'.