Manipulating social cues in baboon gesture learning: what does it tell us about the evolution of communication?

Reading the attentional state of an audience is crucial for effective intentional communication. This study investigates how individual learning experience affects subsequent ability to tailor gestural communication to audience visual attention. Olive baboons were atypically trained to request food with gestures by a human standing in profile, while not having access to her face. They were tested immediately after training, and then 1 year later in conditions that varied the human's cues to attention. In immediate testing, these baboons (profile group baboons) gestured towards untrained cues regardless of their relevance for visual communication. They were also less discriminant towards trained versus untrained cues than baboons trained by a human facing them (face group baboons, tested in Bourjade et al. Anim Behav 87:121-128; Bourjade et al., Anim Behav 87:121-128, 2014). In delayed testing, the number of gestures towards meaningful untrained cues increased and profile group baboons discriminated the orientation of the human body, a conspicuous proxy of visual attention. Our results provide support for the primary interplay between implicit learning and systematically reinforced associations made through explicit training in the scaffolding of intentional gesturing tuned to audience attention.

Safety Profile and Immunologic Responses of a Novel Vaccine Against Shigella sonnei Administered Intramuscularly, Intradermally and Intranasally: Results From Two Parallel Randomized Phase 1 Clinical Studies in Healthy Adult Volunteers in Europe.

BACKGROUND: Approximately 164,000 deaths yearly are due to shigellosis, primarily in developing countries. Thus, a safe and affordable Shigella vaccine is an important public health priority. The GSK Vaccines Institute for Global Health (GVGH) developed a candidate Shigella sonnei vaccine (1790GAHB) using the Generalized Modules for Membrane Antigens (GMMA) technology. The paper reports results of 1790GAHB Phase 1 studies in healthy European adults. METHODS: To evaluate the safety and immunogenicity profiles of 1790GAHB, we performed two parallel, phase 1, observer-blind, randomized, placebo-controlled, dose escalation studies in France ("study 1") and the United Kingdom ("study 2") between February 2014 and April 2015 (ClinicalTrials.gov, number NCT02017899 and NCT02034500, respectively) in 18-45years old subjects (50 in study 1, 52 in study 2). Increasing doses of Alhydrogel adsorbed 1790, expressed by both O Antigen (OAg) and protein quantity, or placebo were given either by intramuscular route (0.059/1, 0.29/5, 1.5/25, 2.9/50, 5.9/100µg of OAg/µg of protein; study 1) or by intradermal (ID), intranasal (IN) or intramuscular (IM) route of immunization (0.0059/0.1, 0.059/1, 0.59/10µg ID, 0.29/5, 1.2/20, 4.8/80µg IN and 0.29/5µg IM, respectively; study 2). In absence of serologic correlates of protection for Shigella sonnei, vaccine induced immunogenicity was compared to anti-LPS antibody in a population naturally exposed to S. sonnei. FINDINGS: Vaccines were well tolerated in both studies and no death or vaccine related serious adverse events were reported. In study 1, doses ≥1.5/25µg elicited serum IgG median antibody greater than median level in convalescent subjects after the first dose. No vaccine group in study 2 achieved median antibody greater than the median convalescent antibody. INTERPRETATION: Intramuscularly administered Shigella sonnei GMMA vaccine is well tolerated, up to and including 5.9/100µg and induces antibody to the OAg of at least the same magnitude of those observed following natural exposure to the pathogen. Vaccine administered by ID or IN, although well tolerated, is poorly immunogenic at the doses delivered. The data support the use of the GMMA technology for the development of intramuscular multivalent Shigella vaccines.

Object-specific and relational learning in pigeons.

Abstract or relational stimulus processing requires an organism to appreciate the interrelations between or among two or more stimuli (e.g., same or different, less than or greater than). In the current study, we explored the role of concrete and abstract information processing in pigeons performing a visual categorization task which could be solved by attending to either the specific objects presented or the relation among the objects. In Experiment 1, we gave pigeons three training phases in which we gradually increased the variability (that is, the number of object arrays) in the training set. In Experiment 2, we trained a second group of pigeons with an even larger number of object arrays from the outset. We found that, the larger the variability in the training exemplars, the lesser the pigeons' attention to object-specific information and the greater their attention to relational information; nevertheless, the contribution of object-specific information to categorization performance was never completely eliminated. This pervasive influence of object-specific information is not peculiar to animals, but has been observed in young children and human adults as well.

Effects of training condition on the contribution of specific items to relational processing in baboons (Papio papio).

Relational processing involves learning about the relationship between or among stimuli, transcending the individual stimuli, so that abstract knowledge generalizable to novel situations is acquired. Relational processing has been studied in animals as well as in humans, but little attention has been paid to the contribution of specific items to relational thinking or to the factors that may affect that contribution. This study assessed the intertwined effects of item and relational processing in nonhuman primates. Using a procedure that entailed both expanding and contracting sets of pictorial items, we trained 13 baboons on a two-alternative forced-choice task, in which they had to distinguish horizontal from vertical relational patterns. In Experiment 1, monkeys engaged in item-based processing with a small training set size, and they progressively engaged in relation-based processing as training set size was increased. However, in Experiment 2, overtraining with a small stimulus set promoted the processing of item-based information. These findings underscore similarities in how humans and nonhuman primates process higher-order stimulus relations.

Patterns of hemispheric specialization for a communicative gesture in different primate species.

We review four studies investigating hand preferences for grasping versus pointing to objects at several spatial positions in human infants and three species of nonhuman primates using the same experimental setup. We expected that human infants and nonhuman primates present a comparable difference in their pattern of laterality according to tasks. We tested 6 capuchins, 6 macaques, 12 baboons, and 10 human infants. Those studies are the first of their kind to examine both human infants and nonhuman primate species with the same communicative task. Our results show remarkable convergence in the distribution of hand biases of human infants, baboons and macaques on the two kinds of tasks and an interesting divergence between capuchins' and other species' hand preferences in the pointing task. They support the hypothesis that left-lateralized language may be derived from a gestural communication system that was present in the common ancestor of macaques, baboons and humans.

Contribution of working memory processes to relational matching-to-sample performance in baboons (Papio papio).

Recent studies of monkeys and apes have shown that these animals can solve relational-matching-to-sample (RMTS) problems, suggesting basic abilities for analogical reasoning. However, doubts remain as to the actual cognitive strategies adopted by nonhuman primates in this task. Here, we used dual-task paradigms to test 10 baboons in the RMTS problem under three conditions of memory load. Our three test conditions allowed different predictions, depending on the strategy (i.e., flat memorization of the percept, reencoding of the percept, or relational processing) that they might use to solve RMTS problems. Results support the idea that the baboons process both the items and the abstract (same and different) relations in this task.

Analogical reasoning in baboons (Papio papio): flexible reencoding of the source relation depending on the target relation.

Analogical reasoning is a cornerstone of human cognition, but the extent and limits of analogical reasoning in animals remains unclear. Recent studies have demonstrated that apes and monkeys can match relations with relations, suggesting that these species have the basic abilities for analogical reasoning. However, analogical reasoning in humans entails two additional cognitive processes that remain unexplored in animals. These include the ability to (1) flexibly reencode the relations instantiated by the source domain as a function of the relational properties of the target domain, and (2) to match relations across different stimulus dimensions. Using a two-dimensional relational matching-to-sample task, the present study demonstrates that these two abilities are in the scope of baboons, given appropriate training. These findings unveil the richness of the cognitive processes implicated during analogical reasoning in nonhuman primates and further reduce the apparent gap between animal and human cognition.