As social and cultural psychologists of learning, we are persuaded of the crucial role of interaction in development and learning. But how do we experience this assumption in our own research practices and in our collaboration with colleagues? Taking as our object of study our own participation in a European Research and Development project that aimed to enhance interactive and argumentative skills in learning settings, this study shows how collaboration among project partners is not something that is to be taken for granted, but something that is elaborated and evolves in time, takes diverse forms, and is mediated by multiple tools. The psychological processes--more particularly tensions and negotiation--involved in collaboration are developed and discussed. The study explores the processes of establishing collaboration and, through the analysis of specific zones of tensions, sheds light on the way new knowledge (on how to do research, how to communicate, how to work together) is constructed. It contributes to the understanding of the issues and conditions for the development of a community of practice.

ICT tools have been developed to facilitate web-based learning through and learning about argumentation. In this paper we will present an example of a learning activity mediated by Digalo-software for knowledge sharing through visually supported discussiondeveloped in a university setting. Our aim is to examine, in particular, socio-cognitive construction of knowledge and argumentation by students debating a controversial question in history. We propose a descriptive approach of understanding and meaning-making processes based on two levels of analysis: (1) a topic meaning-making process oriented level and (2) an argumentation oriented level. We focus our studies on how the participants-small groups of students-develop understanding of the topic, their arguments and their interactions through the use of different functionalities of this software. Our results show that interactive and argumentative processes are themselves objects of learning and develop through collective activity. Development of the understanding of the topic through argumentation is discussed and linked to the design of the activity and the affordances of the Digalo software.

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The research is about the construction of conventional time through the appropriation of different tools used to locate events in time by 200 children between the ages of 4 to 10 years old. Temporal locations are examined through an interview task and the children's ability to construct order of different temporal frameworks (daily , weekly, yearly) is studied using a card arrangement task. The same children took part in these two tasks.The results show that the tools children use to locate events in time change with their age and school experience: the youngest use relative locations or scripts (events are used as tools to locate other events) whereas older children use absolute location s (hours. days. months then become tools fo r locating events in time). Moreover, children use conventional temporal tools to locate events before being able to use them to put different events into the same temporal sequence. The study highlights developmental phases between the use of temporal locations and the construction oftheir meanings.In developmental psychology, there have been relatively few studies on the acquisition of conventional time knowledge (Friedman, 1978(Friedman, , 1982. For the most part, developmental works on time have been focused on understanding duration and the logical relations between time, distance and speed as initiated by Piaget (1946Piaget ( /1969.The present research focused on the development of the means children use to locate events in time. Young children use very early temporal words such as "yesterday", "Saturday" (Hamer, 1975;Weist, 1989;Nelson, 1991). Although adults and children both use the same words to talk about events they do not really reflect to the same meanings. These results led Levy and Nelson (1994) to talk about "use before meaning" in order to qualify the first incomplete meaning of temporal expressions children use in relation to adults' stable meanings. This study is designed to test whether children of different ages use different tools to locate events temporally and to establish temporal order. It involved an interview task and an ordering card task in which 200 children from 4-to lO-years old participated. The findings I would like to thank Michel Brossard for his insightful comment s on an earlier draft of this paper; all the childre n and teachers who took part in this study.