Signatures of adaptive evolution in platyrrhine primate genomes

The family Cebidae (capuchin and squirrel monkeys) form a remarkable platyrrhine clade exhibiting among the largest primate encephalisation quotients. Each cebid lineage is characterised by notable lineage-specific traits, with capuchins showing striking similarities to Hominidae including high sensorimotor intelligence with tool use, advanced cognitive abilities, and behavioural flexibility. Here, we take a comparative genomics approach, analysing five cebid branches including successive lineages, to infer a stepwise timeline for cebid adaptive evolution. We uncover candidate targets of selection across various periods of cebid evolution that may underlie the emergence of lineage-specific traits. Our analyses highlight shifting and sustained selective pressures on genes related to brain development, longevity, reproduction, and morphology, including evidence for cumulative and diversifying neurobiological adaptations over cebid evolutionary history. In addition to generating a new, high-quality reference genome assembly for robust capuchins, our results lend to a better understanding of the adaptive diversification of this distinctive primate clade.

Infant Intentions: The role of agency in learning with affectionate companions

A young child moves with her own agency or initiative, using a dexterous body to create experiences she enjoys and learns, enabling early development of a ‘sensorimotor intelligence’ for her own benefit. She is also born with ‘affectionate social intelligence’, wanting to share discoveries of experience and to build their meaning with parents and playmates as companions. This learning is evident in the fine control of movements before birth, in the gestures and expressions of the mid-gestation foetus that demonstrate an awareness and a curious interest in the world, and that respond to behaviours of the mother and other persons they can sense near them. They are especially receptive to rhythms of other persons’ locomotion, speech and dance or music, and they learn to recognise and prefer their mother’s voice. Innate movements, guided by anticipations of their future effects, are adapted to gain benefits from the world in cooperation with other persons’ interests and responses. Infant movements, even if they are simple and discrete, are formed as the actions of a person, an intentional social agent from the start who is seeking to share cultural habits and skills. Self-generated movements develop in reach and capacity from early single actions with immediate proximal goals, to the complex serial ordering of actions that construct projects extended through space and time. They become described in abstract, culturally learned, and conceptually-backed stories as the infant builds knowledge and becomes a lively and curious toddler. High-precision analysis of movement at birth can detect risk of a developmental disorder that may affect all stages of learning. Children who develop with autism exhibit a subtle, but significant disruption to self-generated movement that appears evident from birth, thwarting its success, creating distress for the child and anxiety for their care-givers. Early motor experience is a fundamental adventure of the young child that expands into social collaboration and the ability to make sense of the world with others’ assistance. The enterprise of the human spirit from early and simple actions to later complex projects of serially-ordered actions confirms the existence of a primary form of intentionality that is a driver for learning and its education at all ages.

Collaborative sensorimotor intelligence: the scrum as a model

AimUsing M-Rex, a rugby scrum simulator, we developed tools to describe scrummaging forces and to prevent accident.MethodsWe tested three groups of frontliners at national level. The simulator was passive or responded to the player(s) to simulate the reaction of opposite players. Sensors in the beam measured the force exerted by each of the players. Their movements were recorded with a Codamotion system.ResultsThe force signals exhibited two phases: a transient phase, similar to a damped sinusoid with a dominant frequency around 5 Hz when the players scrummaged alone and with a wider range when playing together; then, a sustained phase could be decomposed in two components: a DC component remained stable whether frontliners played alone or together. In contrast, its variability decreased when the frontliners played together compared with when they played alone. As for the oscillations, the frontliners exhibited a large variability in their ability to synchronise their efforts during the sustained phase. The synchronisation between the hooker and the props was quite efficient, while it was always missing between two props. Finally, we were able to study postural readjustments and their synchronisation among players during the sustained phase.ConclusionThis study shows that by using adequate methods, it is possible to assess the frontline collective intelligence. These findings may pave the way for innovative methods of training to improve players’ collective behaviour.

Novel plasticity rule can explain the development of sensorimotor intelligence

Grounding autonomous behavior in the nervous system is a fundamental challenge for neuroscience. In particular, self-organized behavioral development provides more questions than answers. Are there special functional units for curiosity, motivation, and creativity? This paper argues that these features can be grounded in synaptic plasticity itself, without requiring any higher-level constructs. We propose differential extrinsic plasticity (DEP) as a new synaptic rule for self-learning systems and apply it to a number of complex robotic systems as a test case. Without specifying any purpose or goal, seemingly purposeful and adaptive rhythmic behavior is developed, displaying a certain level of sensorimotor intelligence. These surprising results require no system-specific modifications of the DEP rule. They rather arise from the underlying mechanism of spontaneous symmetry breaking, which is due to the tight brain body environment coupling. The new synaptic rule is biologically plausible and would be an interesting target for neurobiological investigation. We also argue that this neuronal mechanism may have been a catalyst in natural evolution.