The Potter's Wheel: Craft Specialization and Technical Competence

The book comprises two ethnoarchaeological studies whose aim is the construction of a reference knowledge for interpreting archaeological data, according to the principles of verification against empirical data. The first study deals with the concept of craft specialization. This is a commonly encountered concept since it describes the emergence of complex societies. The question is to find material critria significant of pottery specialization that are receivable from an epistemological point of view. With this purpose in mind, the authors conducted a study on apprenticeship in wheel throwing technique. Perceptual motor tests, potters' gestures and experimental products are studied. They show that the apprenticeship in throwing technique is necessarily long and difficult taking into account the motor activities which have to be developed. Based on this, the authors propose to associate the material fact "throwing technique" to the attribute "craft specialization". The second study is the construction of a techno-morphological taxonomy to evaluate the throwing difficulties of pre- and protohistoric ceramic vessels. The techno-morphological taxonomy is constructed on the basis of Indian potter's classification and explanations. The validity of the oral data is assessed by analysing an experimental production in terms of measures, manufacturing time, and thinning and shaping gestures. Then, the transcultural value of the taxinomy is discussed on the basis of an investigation with French potters

Assessing the Impact of Movement Consequences on the Development of Early Reaching in Infancy

Prior research on infant reaching has shown that providing infants with repeated opportunities to reach for objects aids the emergence and progression of reaching behavior. This study investigated the effect of movement consequences on the process of learning to reach in pre-reaching infants. Thirty-five infants aged 2.9 months at the onset of the study were randomly assigned to 1 of 3 groups. Two groups received a 14-day intervention to distinct reaching tasks: (1) in a contingent group, a toy target moved and sounded upon contact only, and (2) in a continuous group, the toy moved and sounded continuously, independent of hand-toy contact. A third control group did not receive any intervention; this group’s performance was assessed only on 2 days at a 15-day interval. Results revealed that infants in the contingent group made the most progress over time compared to the two other groups. Infants in this group made significantly more overall contacts with the sounding/moving toy, and they increased their rate of visually attended target contacts relative to non-visually attended target contacts compared to the continuous and control groups. Infants in the continuous group did not differ from the control group on the number of hand-toy contacts nor did they show a change in visually attended target versus non-visually attended target contacts ratio over time. However, they did show an increase in movement speed, presumably in an attempt to attain the moving toy. These findings highlight the importance of contingent movement consequences as a critical reinforcer for the selection of action and motor learning in early development. Through repeated opportunities to explore movement consequences, infants discover and select movements that are most successful to the task-at-hand. This study further demonstrates that distinct sensory-motor experiences can have a significant impact on developmental trajectories and can influence the skills young infants will discover through their interactions with their surroundings

Assessing the Impact of Movement Consequences on the Development of Early Reaching in Infancy

Prior research on infant reaching has shown that providing infants with repeated opportunities to reach for objects aids the emergence and progression of reaching behavior. This study investigated the effect of movement consequences on the process of learning to reach in pre-reaching infants. Thirty-five infants aged 2.9 months at the onset of the study were randomly assigned to 1 of 3 groups. Two groups received a 14-day intervention to distinct reaching tasks: (1) in a contingent group, a toy target moved and sounded upon contact only, and (2) in a continuous group, the toy moved and sounded continuously, independent of hand-toy contact. A third control group did not receive any intervention; this group’s performance was assessed only on 2 days at a 15-day interval. Results revealed that infants in the contingent group made the most progress over time compared to the two other groups. Infants in this group made significantly more overall contacts with the sounding/moving toy, and they increased their rate of visually attended target contacts relative to non-visually attended target contacts compared to the continuous and control groups. Infants in the continuous group did not differ from the control group on the number of hand-toy contacts nor did they show a change in visually attended target versus non-visually attended target contacts ratio over time. However, they did show an increase in movement speed, presumably in an attempt to attain the moving toy. These findings highlight the importance of contingent movement consequences as a critical reinforcer for the selection of action and motor learning in early development. Through repeated opportunities to explore movement consequences, infants discover and select movements that are most successful to the task-at-hand. This study further demonstrates that distinct sensory-motor experiences can have a significant impact on developmental trajectories and can influence the skills young infants will discover through their interactions with their surroundings

Brain reorganization as a function of walking experience in 12-month-old infants: implications for the development of manual laterality

Hand preference in infancy is marked by many developmental shifts in hand use and arm coupling as infants reach for and manipulate objects. Research has linked these early shifts in hand use to the emergence of fundamental postural–locomotor milestones. Specifically, it was found that bimanual reaching declines when infants learn to sit; increases if infants begin to scoot in a sitting posture; declines when infants begin to crawl on hands and knees; and increases again when infants start walking upright. Why such pattern fluctuations during periods of postural–locomotor learning? One proposed hypothesis is that arm use practiced for the specific purpose of controlling posture and achieving locomotion transfers to reaching via brain functional reorganization. There has been scientific support for functional cortical reorganization and change in neural connectivity in response to motor practice in adults and animals, and as a function of crawling experience in human infants. In this research, we examined whether changes in neural connectivity also occurred as infants coupled their arms when learning to walk and whether such coupling mapped onto reaching laterality. Electroencephalogram (EEG) coherence data were collected from 43 12-month-old infants with varied levels of walking experience. EEG was recorded during quiet, attentive baseline. Walking proficiency was laboratory assessed and reaching responses were captured using small toys presented at mid-line while infants were sitting. Results revealed greater EEG coherence at homologous prefrontal/central scalp locations for the novice walkers compared to the prewalkers or more experienced walkers. In addition, reaching laterality was low in prewalkers and early walkers but high in experienced walkers. These results are consistent with the interpretation that arm coupling practiced during early walking transferred to reaching via brain functional reorganization, leading to the observed developmental changes in manual laterality

Changes in Posture and Interactive Behaviors as Infants Progress From Sitting to Walking: A Longitudinal Study

This longitudinal study assessed how infants and mothers used different postures and modulated their interactions with their surroundings as the infants progressed from sitting to walking. Thirteen infants and their mothers were observed biweekly throughout this developmental period during 10 min laboratory free-play sessions. For every session, we tracked the range of postures mothers and infants produced (e.g., sitting, kneeling, and standing), we assessed the type of interactions they naturally engaged in (no interactions, passive involvement, fine motor manipulation, or gross motor activity), and documented all target transitions. During the crawling transition period, when infants used sitting postures, they engaged mainly in fine motor manipulations of targets and often maintained their activity on the same target. As infants became mobile, their rate of fine motor manipulation declined during sitting but increased while kneeling/squatting. During the walking transition, their interactions with targets became more passive, particularly when sitting and standing, but they also engaged in greater gross motor activity while continuing to use squatting/kneeling postures for fine motor manipulations. The walking period was also marked by an increase in target changes and more frequent posture changes during object interactions. Throughout this developmental period, mothers produced mainly no or passive activity during sitting, kneeling/squatting, and standing. As expected, during this developmental span, infants used their body in increasingly varied ways to explore and interact with their environment, but more importantly, progression in posture variations significantly altered how infants manually interacted with their surrounding world

Mapping the feel of the arm with the sight of the object: on the embodied origins of infant reaching

For decades, the emergence and progression of infant reaching was assumed to be largely under the control of vision. More recently, however, the guiding role of vision in the emergence of reaching has been downplayed. Studies found that young infants can reach in the dark without seeing their hand and that corrections in infants\u27 initial hand trajectories are not the result of visual guidance of the hand, but rather the product of poor movement speed calibration to the goal. As a result, it has been proposed that learning to reach is an embodied process requiring infants to explore proprioceptively different movement solutions, before they can accurately map their actions onto the intended goal. Such an account, however, could still assume a preponderant (or prospective) role of vision, where the movement is being monitored with the scope of approximating a future goal-location defined visually. At reach onset, it is unknown if infants map their action onto their vision, vision onto their action, or both. To examine how infants learn to map the feel of their hand with the sight of the object, we tracked the object-directed looking behavior (via eye-tracking) of three infants followed weekly over an 11-week period throughout the transition to reaching. We also examined where they contacted the object. We find that with some objects, infants do not learn to align their reach to where they look, but rather learn to align their look to where they reach. We propose that the emergence of reaching is the product of a deeply embodied process, in which infants first learn how to direct their movement in space using proprioceptive and haptic feedback from self-produced movement contingencies with the environment. As they do so, they learn to map visual attention onto these bodily centered experiences, not the reverse. We suggest that this early visuo-motor mapping is critical for the formation of visually-elicited, prospective movement control

A Naturalistic Observation of Spontaneous Touches to the Body and Environment in the First 2 Months of Life

Self-generated touches to the body or supporting surface are considered important contributors to the emergence of an early sense of the body and self in infancy. Both are critical for the formation of later goal-directed actions. Very few studies have examined in detail the development of these early spontaneous touches during the first months of life. In this study, we followed weekly four infants in two naturalistic 5-min sessions (baseline and toys-in-view) as they laid alert in supine from the age of 3 weeks until they acquired head control. We found that throughout the 2 months of observation, infants engaged in a high rate of touch and spent about 50% of the time moving their hands from one touch location to the next. On most sessions, they produced up to 200 body/surface contacts and touched as many as 18 different areas (mainly upper body and floor) both hands combined. When we did not consider the specific areas touched, the rates of touches were higher to the body than to the floor, but the duration of contacts and the most touched areas were higher for the supporting surface than for the body. Until the age of 9 weeks, we found no consistent differences in the rate of touch between head and trunk. Infants also did not display significant differences in their rate of touch between right and left hand or between conditions. However, we discovered that in the earlier weeks, infants engaged more often in what we called “complex touches.” Complex touches were touches performed across several body/floor areas in one continuous bout while the hand maintained contact with the body or floor. Single touches, in contrast, corresponded to one touch to one single body or floor area at a time. We suggest that infants are active explorers of their own body and peripersonal space from day 1 and that these early self-generated and deeply embodied sensorimotor experiences form the critical foundation from which future behaviors develop

SNPs and real-time quantitative PCR method for constitutional allelic copy number determination, the VPREB1 marker case

<p>Abstract</p> <p>Background</p> <p>22q11.2 microdeletion is responsible for the DiGeorge Syndrome, characterized by heart defects, psychiatric disorders, endocrine and immune alterations and a 1 in 4000 live birth prevalence. Real-time quantitative PCR (qPCR) approaches for allelic copy number determination have recently been investigated in 22q11.2 microdeletions detection. The qPCR method was performed for 22q11.2 microdeletions detection as a first-level screening approach in a genetically unknown series of patients with congenital heart defects. A technical issue related to the <it>VPREB1 </it>qPCR marker was pointed out.</p> <p>Methods</p> <p>A set of 100 unrelated Italian patients with congenital heart defects were tested for 22q11.2 microdeletions by a qPCR method using six different markers. Fluorescence In Situ Hybridization technique (FISH) was used for confirmation.</p> <p>Results</p> <p>qPCR identified six patients harbouring the 22q11.2 microdeletion, confirmed by FISH. The <it>VPREB1 </it>gene marker presented with a pattern consistent with hemideletion in one 3 Mb deleted patient, suggestive for a long distal deletion, and in additional five non-deleted patients. The long distal 22q11.2 deletion was not confirmed by Comparative Genomic Hybridization. Indeed, the <it>VPREB1 </it>gene marker generated false positive results in association with the rs1320 G/A SNP, a polymorphism localized within the <it>VPREB1 </it>marker reverse primer sequence. Patients heterozygous for rs1320 SNP, showed a qPCR profile consistent with the presence of a hemideletion.</p> <p>Conclusions</p> <p>Though the qPCR technique showed advantages as a screening approach in terms of cost and time, the <it>VPREB1 </it>marker case revealed that single nucleotide polymorphisms can interfere with qPCR data generating erroneous allelic copy number interpretations.</p