While craft apprenticeship can be understood as socially mediated individual learning, the ensuin... more While craft apprenticeship can be understood as socially mediated individual learning, the ensuing prediction of individual and cultural object traits within craft communities has not been investigated. Here we provide an assessment of vessel shape variations occurring through cultural transmission and their visual perception by the craftsmen. To this end, 26 Hebron potters distributed through nine familial transmission units were asked to produce vessels of three different pottery types, then 21 of the participants were invited to visually identify their proper vessels and those of five other potters. We used the Elliptical Fourier method to analyze vessel shape variation among the productions. Our findings demonstrated that the learning process modified the ceramic shape, the cultural morphological traits being combined with new individual traits. Moreover, the individual morphological traits overtook the cultural ones, which is supposed to lead to divergence of vessel shapes within the transmission chain. If certain cultural morphological traits perpetuate through generations, this certainly does not result from fidelity copying occurring through learning but from stabilizing mechanisms such as consumer demand. Our results showed that potters do perceive the subtle same-type vessel shape variations and thereby could select the individual variant they prefer to produce.
The present study examined rotation velocity regulation in pottery wheel-throwing. Long assumed t... more The present study examined rotation velocity regulation in pottery wheel-throwing. Long assumed to be a key parameter in the control of the centrifugal force, we interpret its role rather as a means to control the linear velocity at the point of hand-clay contact. To test this hypothesis, we set up a field experiment with Indian potters working with a low-inertia kick-wheel. Six expert potters were asked to produce eight types of pots (four shapes x two masses), each type in five specimens (in total each potter threw 40 vessels). We measured the rotation velocity during the pre-forming and forming fashioning phases, as well as the maximal vessel radii at the end of both phases. Results demonstrated that potters reduced the rotation velocity from the pre-forming phase to the forming phase, but also for the large clay masses compared to the small clay masses, and -uniquely during the forming phase- for the shapes characterized by the largest diameter. Overall, the observed decreases in rotation velocity corresponded to increases in mean vessel diameter, suggesting that the potters were applying a limit on the linear velocity. Our results thus provide empirical evidence supporting the role of linear velocity as a key functional parameter in wheel-throwing. Directly relating to the potter-vessel interaction, it indicates both when and by how much the rotation velocity deceleration caused by the exertion of manual pressure forces should be compensated, as well as how to avoid the risk of velocity-induced collapse. While only preliminary, our results also suggest that large-sized ancient wheel-thrown vessels were most likely produced using low-velocity and high-inertia wheels. Future work, examining rotation velocity regulation over different types of wheels, is needed to allow definite conclusions to be drawn.
Studies have documented that traditional motor skills (i.e. motor habits) are part of the cultura... more Studies have documented that traditional motor skills (i.e. motor habits) are part of the cultural way of life that characterises each society. Yet, it is still unclear to what extent motor skills are inherited through culture. Drawing on ethnology and motor behaviour, we addressed this issue through a detailed description of traditional pottery skills. Our goal was to quantify the influence of three kinds of constraints: the transcultural constraints of wheel-throwing, the cultural constraints induced via cultural transmission, and the potters' individual constraints. Five expert Nepalese potters were invited to produce three familiar pottery types, each in five specimens. A total of 31 different fashioning hand positions were identified. Most of them (14) were cross-cultural, ten positions were cultural, five positions were individual, and two positions were unique. Statistical tests indicated that the subset of positions used by the participants in this study were distinct from those of other cultural groups. Behaviours described in terms of fashioning duration, number of gestures, and hand positions repertoires size highlighted both individual and cross-cultural traits. We also analysed the time series of the successive hand positions used throughout the fashioning of each vessel. Results showed, for each pottery type, strong reproducible sequences at the individual level and a clearly higher level of variability between potters. Overall, our findings confirm the existence of a cultural transmission in craft skills but also demonstrated that the skill is not fully determined by a cultural marking. We conclude that the influence of culture on craft skills should not be overstated, even if its role is significant given the fact that it reflects the socially transmitted part of the skill. Such research offers insights into archaeological problems in providing a representative view of how cultural constraints influence the motor skills implied in artefact manufacturing.
Ceramics are quintessential indicators of human culture and its evolution across generations of s... more Ceramics are quintessential indicators of human culture and its evolution across generations of social learners. Cultural transmission and evolution theory frequently emphasizes apprentices’ need for accurate imitation (high-fidelity copying) of their mentors’ actions. However, the ensuing prediction of standardized fashioning patterns within communities of practice has not been directly addressed in handicraft traditions such as pottery throwing. To fill this gap, we analysed variation in vessel morphogenesis amongst and within traditional potters from culturally different workshops producing for the same market. We demonstrate that, for each vessel type studied, individual potters reliably followed distinctive routes through morphological space towards a much-less-variable common final shape. Our results indicate that mastering the pottery handicraft does not result from accurately reproducing a particular model behaviour specific to the community’s cultural tradition. We provide evidence that, at the level of the elementary clay-deforming gestures, individual learning rather than simple imitation is required for the acquisition of a complex motor skill such as throwing pottery.
This work aims to improve understanding of the conditions favoring adoption of new craft traits. ... more This work aims to improve understanding of the conditions favoring adoption of new craft traits. We investigated the cost of motor skill adaptation in asking seven expert potters to produce familiar vs. unfamiliar shapes and using a familiar vs. unfamiliar wheel. The gestural patterns of the potters (i.e. the succession of their hand positions) were videotaped for quantitative analysis. Results showed that the hand positions varied mostly according to the shape being thrown, whether that shape was familiar or not. Additionally, all potters transferred a major part of their hand positions repertoire from the familiar shapes to the unfamiliar ones. Hence, expert potters produce novel shapes through individual learning which constitutes a low cost of adaptation. In archaeological contexts where ceramic production was distributed among multiple expert potters, new vessel shapes could easily have been adopted because the individual cost was low. On the other hand, we hypothesize that low-skilled potters (e.g. potters specializing in small vessels) would not have achieved such adoption without opportunities for social learning. As for the unfamiliar wheels, results indicated that their use did not influence the hand positions but involved new postures that may be difficult to adopt, this merits further studies.
At the crossroad of archaeology and experimental psychology, we addressed the issue of inter-indi... more At the crossroad of archaeology and experimental psychology, we addressed the issue of inter-individual variability in traditional ceramic shapes. The goal was to explore whether such variability could imply potter signatures. We setup a field experiment with five expert Nepalese potters, asking them to produce three shapes (replicated five times). The 2D profiles of the experimental productions were analyzed with a shape analysis method borrowed from biology. In a complementary experiment focusing on shape discrimination, the participants were asked to visually identify their own productions and those of their colleagues. Results indicated that the potters produced slightly but significantly different shapes. We assume that during apprenticeship individuals developed their own motor skills, which reflect upon the finished products. Interpreting shape variability in terms of individuals could provide supplementary information on the social organization of the production, either for modern or ancient periods. As for shape discrimination, our preliminary results indicated that a few potters visually distinguished individual signatures. Those craftsmen could play a key role in the selection and evolution of the traditional ceramic shapes.
Traditional motor skills are culturally transmitted across generations. Yet, the question remains... more Traditional motor skills are culturally transmitted across generations. Yet, the question remains to what extent a motor skill developed within a given cultural setting corresponds to a model specific to this cultural setting. In this article we present, within the theoretical framework of ecological psychology, the behavioural mechanisms underlying the cultural transmission of motor skills as well as some of our experimental results evaluating the influence of cultural models on the potter’s motor skill of wheel-throwing. By analysing the hand positions used by expert French and Indian potters, we were able to demonstrate that their skills indeed reveal cultural models transmitted in the course of learning. However, such models are not completely specific to a given cultural context, as they also contain transcultural hand positions determined by the task constraints. Moreover, the identification of individual-specific hand positions confirmed that learning should not be understood as resulting from simply copying a model, but rather as an individual reappropriation of this model. Finally, we observed that the two Indian communities studied, Prajapati and Multani Kumhar, shared almost the same repertoire of positions. This reveals the existence of intercultural borrowings that merit to be more widely studied.
This study is aimed at evaluating potters’ skills according to the mechanical characteristics of ... more This study is aimed at evaluating potters’ skills according to the mechanical characteristics of the vessels they produced. It focuses on wheel thrown vessels. In a first stage, considering that the difficulty of throwing ceramic vessels is to a significant extent determined by the risk of collapse of the thrown structure, we applied the method of finite element modelling to derive an index of mechanical stresses operating within a vessel. Validated via compression tests, the so-called Von Mises stress index was employed as a global index of mechanical difficulty. Because this index allows comparisons between vessels of different form, mass, and clay properties, it provides a more powerful tool than existing techno-morphological taxonomies. In a second stage, in order to relate the Von Mises stress index to throwing difficulty, we analysed the geometrical and mechanical characteristics of vessels thrown by eleven expert potters invited to reproduce four different model forms with two different masses of clay. The results demonstrated that reproductions revealed subtle but systematic deviations from the model forms that allowed a decrease in the mechanical difficulty. More difficult forms showed larger degrees of mechanical optimisation. These results, in combination with a new analysis of data from Roux’s (1990) study with potters of different skill levels, indicate that skill resides, at least to a certain extent, in the capacity to marshal the operative mechanical constraints. In other words, the latter, measured by the Von Mises index, provides a useful signature of a potter’s skills.► Expert potters threw vessels of different form and mass. ► Finite element modelling of vessels allowed calculation of mechanical stresses. ► The Von Mises stress index captures the difficulty of throwing different vessels. ► Geometrical deformations observed in thrown forms reveal mechanical optimisation. ► Skill can be inferred from mechanical analysis of ancient thrown vessels.
While craft apprenticeship can be understood as socially mediated individual learning, the ensuin... more While craft apprenticeship can be understood as socially mediated individual learning, the ensuing prediction of individual and cultural object traits within craft communities has not been investigated. Here we provide an assessment of vessel shape variations occurring through cultural transmission and their visual perception by the craftsmen. To this end, 26 Hebron potters distributed through nine familial transmission units were asked to produce vessels of three different pottery types, then 21 of the participants were invited to visually identify their proper vessels and those of five other potters. We used the Elliptical Fourier method to analyze vessel shape variation among the productions. Our findings demonstrated that the learning process modified the ceramic shape, the cultural morphological traits being combined with new individual traits. Moreover, the individual morphological traits overtook the cultural ones, which is supposed to lead to divergence of vessel shapes within the transmission chain. If certain cultural morphological traits perpetuate through generations, this certainly does not result from fidelity copying occurring through learning but from stabilizing mechanisms such as consumer demand. Our results showed that potters do perceive the subtle same-type vessel shape variations and thereby could select the individual variant they prefer to produce.
The present study examined rotation velocity regulation in pottery wheel-throwing. Long assumed t... more The present study examined rotation velocity regulation in pottery wheel-throwing. Long assumed to be a key parameter in the control of the centrifugal force, we interpret its role rather as a means to control the linear velocity at the point of hand-clay contact. To test this hypothesis, we set up a field experiment with Indian potters working with a low-inertia kick-wheel. Six expert potters were asked to produce eight types of pots (four shapes x two masses), each type in five specimens (in total each potter threw 40 vessels). We measured the rotation velocity during the pre-forming and forming fashioning phases, as well as the maximal vessel radii at the end of both phases. Results demonstrated that potters reduced the rotation velocity from the pre-forming phase to the forming phase, but also for the large clay masses compared to the small clay masses, and -uniquely during the forming phase- for the shapes characterized by the largest diameter. Overall, the observed decreases in rotation velocity corresponded to increases in mean vessel diameter, suggesting that the potters were applying a limit on the linear velocity. Our results thus provide empirical evidence supporting the role of linear velocity as a key functional parameter in wheel-throwing. Directly relating to the potter-vessel interaction, it indicates both when and by how much the rotation velocity deceleration caused by the exertion of manual pressure forces should be compensated, as well as how to avoid the risk of velocity-induced collapse. While only preliminary, our results also suggest that large-sized ancient wheel-thrown vessels were most likely produced using low-velocity and high-inertia wheels. Future work, examining rotation velocity regulation over different types of wheels, is needed to allow definite conclusions to be drawn.
Studies have documented that traditional motor skills (i.e. motor habits) are part of the cultura... more Studies have documented that traditional motor skills (i.e. motor habits) are part of the cultural way of life that characterises each society. Yet, it is still unclear to what extent motor skills are inherited through culture. Drawing on ethnology and motor behaviour, we addressed this issue through a detailed description of traditional pottery skills. Our goal was to quantify the influence of three kinds of constraints: the transcultural constraints of wheel-throwing, the cultural constraints induced via cultural transmission, and the potters' individual constraints. Five expert Nepalese potters were invited to produce three familiar pottery types, each in five specimens. A total of 31 different fashioning hand positions were identified. Most of them (14) were cross-cultural, ten positions were cultural, five positions were individual, and two positions were unique. Statistical tests indicated that the subset of positions used by the participants in this study were distinct from those of other cultural groups. Behaviours described in terms of fashioning duration, number of gestures, and hand positions repertoires size highlighted both individual and cross-cultural traits. We also analysed the time series of the successive hand positions used throughout the fashioning of each vessel. Results showed, for each pottery type, strong reproducible sequences at the individual level and a clearly higher level of variability between potters. Overall, our findings confirm the existence of a cultural transmission in craft skills but also demonstrated that the skill is not fully determined by a cultural marking. We conclude that the influence of culture on craft skills should not be overstated, even if its role is significant given the fact that it reflects the socially transmitted part of the skill. Such research offers insights into archaeological problems in providing a representative view of how cultural constraints influence the motor skills implied in artefact manufacturing.
Ceramics are quintessential indicators of human culture and its evolution across generations of s... more Ceramics are quintessential indicators of human culture and its evolution across generations of social learners. Cultural transmission and evolution theory frequently emphasizes apprentices’ need for accurate imitation (high-fidelity copying) of their mentors’ actions. However, the ensuing prediction of standardized fashioning patterns within communities of practice has not been directly addressed in handicraft traditions such as pottery throwing. To fill this gap, we analysed variation in vessel morphogenesis amongst and within traditional potters from culturally different workshops producing for the same market. We demonstrate that, for each vessel type studied, individual potters reliably followed distinctive routes through morphological space towards a much-less-variable common final shape. Our results indicate that mastering the pottery handicraft does not result from accurately reproducing a particular model behaviour specific to the community’s cultural tradition. We provide evidence that, at the level of the elementary clay-deforming gestures, individual learning rather than simple imitation is required for the acquisition of a complex motor skill such as throwing pottery.
This work aims to improve understanding of the conditions favoring adoption of new craft traits. ... more This work aims to improve understanding of the conditions favoring adoption of new craft traits. We investigated the cost of motor skill adaptation in asking seven expert potters to produce familiar vs. unfamiliar shapes and using a familiar vs. unfamiliar wheel. The gestural patterns of the potters (i.e. the succession of their hand positions) were videotaped for quantitative analysis. Results showed that the hand positions varied mostly according to the shape being thrown, whether that shape was familiar or not. Additionally, all potters transferred a major part of their hand positions repertoire from the familiar shapes to the unfamiliar ones. Hence, expert potters produce novel shapes through individual learning which constitutes a low cost of adaptation. In archaeological contexts where ceramic production was distributed among multiple expert potters, new vessel shapes could easily have been adopted because the individual cost was low. On the other hand, we hypothesize that low-skilled potters (e.g. potters specializing in small vessels) would not have achieved such adoption without opportunities for social learning. As for the unfamiliar wheels, results indicated that their use did not influence the hand positions but involved new postures that may be difficult to adopt, this merits further studies.
At the crossroad of archaeology and experimental psychology, we addressed the issue of inter-indi... more At the crossroad of archaeology and experimental psychology, we addressed the issue of inter-individual variability in traditional ceramic shapes. The goal was to explore whether such variability could imply potter signatures. We setup a field experiment with five expert Nepalese potters, asking them to produce three shapes (replicated five times). The 2D profiles of the experimental productions were analyzed with a shape analysis method borrowed from biology. In a complementary experiment focusing on shape discrimination, the participants were asked to visually identify their own productions and those of their colleagues. Results indicated that the potters produced slightly but significantly different shapes. We assume that during apprenticeship individuals developed their own motor skills, which reflect upon the finished products. Interpreting shape variability in terms of individuals could provide supplementary information on the social organization of the production, either for modern or ancient periods. As for shape discrimination, our preliminary results indicated that a few potters visually distinguished individual signatures. Those craftsmen could play a key role in the selection and evolution of the traditional ceramic shapes.
Traditional motor skills are culturally transmitted across generations. Yet, the question remains... more Traditional motor skills are culturally transmitted across generations. Yet, the question remains to what extent a motor skill developed within a given cultural setting corresponds to a model specific to this cultural setting. In this article we present, within the theoretical framework of ecological psychology, the behavioural mechanisms underlying the cultural transmission of motor skills as well as some of our experimental results evaluating the influence of cultural models on the potter’s motor skill of wheel-throwing. By analysing the hand positions used by expert French and Indian potters, we were able to demonstrate that their skills indeed reveal cultural models transmitted in the course of learning. However, such models are not completely specific to a given cultural context, as they also contain transcultural hand positions determined by the task constraints. Moreover, the identification of individual-specific hand positions confirmed that learning should not be understood as resulting from simply copying a model, but rather as an individual reappropriation of this model. Finally, we observed that the two Indian communities studied, Prajapati and Multani Kumhar, shared almost the same repertoire of positions. This reveals the existence of intercultural borrowings that merit to be more widely studied.
This study is aimed at evaluating potters’ skills according to the mechanical characteristics of ... more This study is aimed at evaluating potters’ skills according to the mechanical characteristics of the vessels they produced. It focuses on wheel thrown vessels. In a first stage, considering that the difficulty of throwing ceramic vessels is to a significant extent determined by the risk of collapse of the thrown structure, we applied the method of finite element modelling to derive an index of mechanical stresses operating within a vessel. Validated via compression tests, the so-called Von Mises stress index was employed as a global index of mechanical difficulty. Because this index allows comparisons between vessels of different form, mass, and clay properties, it provides a more powerful tool than existing techno-morphological taxonomies. In a second stage, in order to relate the Von Mises stress index to throwing difficulty, we analysed the geometrical and mechanical characteristics of vessels thrown by eleven expert potters invited to reproduce four different model forms with two different masses of clay. The results demonstrated that reproductions revealed subtle but systematic deviations from the model forms that allowed a decrease in the mechanical difficulty. More difficult forms showed larger degrees of mechanical optimisation. These results, in combination with a new analysis of data from Roux’s (1990) study with potters of different skill levels, indicate that skill resides, at least to a certain extent, in the capacity to marshal the operative mechanical constraints. In other words, the latter, measured by the Von Mises index, provides a useful signature of a potter’s skills.► Expert potters threw vessels of different form and mass. ► Finite element modelling of vessels allowed calculation of mechanical stresses. ► The Von Mises stress index captures the difficulty of throwing different vessels. ► Geometrical deformations observed in thrown forms reveal mechanical optimisation. ► Skill can be inferred from mechanical analysis of ancient thrown vessels.
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