Learning awakens a variety of internal developmental processes that are able to operate only when the child is interacting with people in his environment and in cooperation with his peers.
(Vygotsky, 1978, p. 90)
Science education is often described as an inquiry oriented process in which students interact and collaborate with their teachers and peers (American Association for the Advancement of Science, 1990; National Research Council, 1996). The demands embedded within this description are complex and call for substantial reform in the pedagogical tools that teacher education programs offer as they prepare preservice teachers with strategies and methodologies that are congruent with constructivist views of learning. Key in the development and acquisition of such pedagogies is the transformation of traditional lectures, at the university level, into active learning experiences. Through experiential learning, preservice teachers may eventually develop the competence and confidence to design classroom instruction that is conducive and reflective of collaborative scientific inquiry (National Research Council, 1996).
Proficiency in the design and implementation of collaborative learning activities can be a complex process. Initially, "expectations for what the teacher can successfully orchestrate should be small and reasonable" (Woolfolk Hoy & Tschannen-Moran, 1999, p. 279). A gradual progression from simple to complex interactive structures allows beginning teachers to reach reasonable goals (Weinstein, 1996) while ensuring that their students acquire social and science related academic skills (Bass, Contant, & Carin, 2009). Learning in dyads, or pairs, represents only one alternative among the variety of group sizes and structures documented in cooperative learning literature that allow preservice teachers to start small (Johnson, Johnson, & Smith, 2006; Kagan, 1994). Learning in dyads has been examined in research (mainly K-12 studies) seeking to measure and describe cognitive and/or academic achievement, together with studies of how and its use revolves around structured or unstructured tasks in which both partners must contribute to both partners' learning (Fawcett & Garton, 2005; Gabrielle, 2007; King & Rosenshine, 1993; Tudge, Winterhoff, & Hogan, 1996). A rationale for the use of dyads in this study will be summarized in terms of the opportunities that dyad structures allow for increased interaction of all group members, positive interdependence, and higher performance output.
First, empirical studies involving structured dyads have found a positive relationship between students' participation in explanatory activities and learning (Okada & Simon, 1997; Rittle-Johnson, Saylor, & Swygert, 2008; Saab, Joolingen, & Hout-Wolters, 2005) as well as in the role of explanation in help giving in collaborative dyads (Veenman & Denessen, 2005). Additionally, Webb and Palincsar (1996) suggest that students in pairs interact more than students in groups of three or four.
Second, collaborative tasks often assume that students will work towards the same goals on equal terms and by helping each other and counting on all individuals' contributions. Studies suggest that students in large groups may avoid the responsibility to help other group members succeed (Johnson et al., 2006; Veenman & Denessen, 2005; Webb, Ender, & Lewis, 1986).
Finally, much of the advantage of dyad learning is linked to the opportunities that dyadic structures provide for verbalization and cognitive engagement (Fawcett & Garton, 2005) versus individualized work or passive listening, the latter of which often results in less creative and less sophisticated answers to questions or tasked posed (De Lisi & Golbeck, 1999). Cooperative learning in dyads places individuals in a position of clarification and evaluation, leading to greater opportunities to engage in complex thinking (Tasley, 1995). …