4. Discussion
The present study set out to investigate game exploration and game efficiency in relation to executive control, vocabulary, and nonverbal reasoning. Our first result was that game exploration depended on the level of the game-play only and that game efficiency related to both the type of game-play and the level of the game-play, as expected. It is therefore feasible to assess children’s exploration and efficiency in scientific thinking using a serious game. In addition, we found the scores for game exploration and efficiency were not significantly related. Therefore, we investigated individual differences separately. Our final result was that attentional control predicted both game exploration and game efficiency. We found the relation between game exploration and attention control to be mediated by vocabulary, and the relation between game efficiency and attention control by nonverbal reasoning. The first result was that the in-game behaviors were related to the level of the game-play. There was less exploration and more efficiency when the level increased. An increase in level meant a decrease in the number of variables. When there are fewer variables, it seemed easier to solve the game-play. This result is in line with other studies on scientific reasoning that found that performance depends on the number of variables. When kindergartners have to predict and explain what side of a balance beam would go down, their performance decreases when they have to incorporate distance (to the fulcrum), besides weight, in their predictions and explanations (Siegler, 1976). Another study on scientific reasoning of kindergartners found that children design fewer experiments correctly when the number of variables they have to set increases (Van der Graaf et al., 2015). The level of the game-play also related to game exploration. When there were fewer variables, there was less exploration. This is in line with the design of the game-plays. When there are fewer variables, there are fewer possibilities to interact with the game, which results in less exploration. Also, the levels with fewer variables were easier to solve, as revealed by the effect of game efficiency. Another aspect of the app was that there were three different game-plays, the slides, the seesaw, and the pendulum. The present results showed that the game-play of the slides was easiest, followed by the seesaw, and that the pendulum was most difficult. The slides were expected to be easiest, because conceptual understanding of the slides is present in kindergartners (Inhelder & Piaget, 1958). Inhelder and Piaget (1958) also described the development of understanding on the seesaw, which, just as Siegler (1976) showed, is difficult for kindergartners, as they experience diffi- culties in identifying distance to the fulcrum as a variable. In their descriptions of the physics topics, Inhelder and Piaget (1958) made clear that complete understanding of the pendulum emerges latest.
