Spontaneous tempo production in cockatiels (Nymphicus hollandicus) and jungle crows (Corvus macrorhynchos).

Musical and rhythmical abilities are poorly documented in non-human animals. Most of the existing studies focused on synchronisation performances to external rhythms. In humans, studies demonstrated that rhythmical processing (e. g. rhythm discrimination or synchronisation to external rhythm) is dependent of an individual measure: the individual tempo. It is assessed by asking participants to produce an endogenous isochronous rhythm (known as spontaneous motor tempo) without any specific instructions nor temporal cue. In non-human animal literature, studies describing spontaneous and endogenous production of motor tempo without any temporal clue are rare. This exploratory study aims to describe and compare the spontaneous motor tempo of cockatiels and jungle crows. Data were collected on spontaneous beak drumming behaviours of birds housed in laboratory. Inter beak strokes intervals were calculated from sound tracks of videos. The analyses revealed that inter beak strokes intervals are non-randomly distributed intervals and are isochronous. Recorded spontaneous motor tempos are significantly different among some cockatiels. Since we could only conduct statistical analysis with one corvid, we cannot conclude about this species. Our results suggest that cockatiels and jungle crows have individual tempos, thus encouraging further investigations.

[The mechanisms involved in rocking toddlers]. / Les mécanismes mis en jeu dans les bercements des tout-petits.

If the tactile modality is fundamental in the infant's experience, there is a particular situation in which it is mobilized: rocking. Carrying a baby in one's arms or trying to soothe him will spontaneously lead the adult to rock him, whatever his culture. The ways of carrying out this rhythmic movement are varied, but all are characterized by a synchronous combination of somesthesic and vestibular stimulations repeated at regular intervals. The specificities of the tactile, vestibular and temporal modalities involved in rocking highlight the way in which rocking provides an essential support to the sensory and social development of the infant.

[Supporting the establishment of the parent-child bond in cases of prematurity]. / Soutenir l'élaboration de la relation parent-enfant en cas de prématurité.

The evolution of the care of premature babies is having an effect on a particular difficulty, that of the development of parenthood and the parent-baby relationship hampered by an early birth. The short- and long-term consequences of any disruption to these two dimensions can be considerable and the hospital must take into account the issue when caring for parents and their premature baby.

Young children's difficulties in switching from rhythm production to temporal interval production (>1 s).

This study examined the young children's abilities to switch from rhythm production, with short inter-tap intervals (ITIs), to temporal interval production, with long ITI (>1 s), in a sensorimotor synchronization task. Children aged 3- and 5-year-olds were given six sessions of synchronization. In a control group, they had to synchronize their ITI to an inter-stimulus interval (ISI) of 4 s. In the experimental group, they must progressively increase their ITI for one session to the next (from 0.4 to 4.0-s ISI). Our results showed that the 5-year-olds produced longer ITI that the 3-year-olds in synchronization. However, the value of ITI in the 5-year-olds never exceeded 1.5 s, with more variable ITI in the control than in the experimental group. In addition, at 5 years, boys had more difficulties than girls in changing their tapping rhythm. These results suggest a temporal window in sensorimotor synchronization, beyond which the rhythm is lost and the synchronization becomes difficult.

Effects of familiarity and attentiveness of partner on 6-month-old infants' social engagement.

This study presents an ecological experiment investigating 6-month-olds' social engagement. Results show that infants look and smile more at a socially attending distant partner than at an inattentive partner and that their looking and smiling behavior is different when the inattentive partner is their mother.