Certain or Possible – Testing the Minimalist Theory of Possibility in Three-year-olds

Abstract

At which age are humans able to conceive of events as being possible instead of merely certain or impossible to occur? On the one hand, there is evidence that 12-month-olds consider multiple possibilities when experiencing ambiguous situations. On the other hand, 3-year-olds fail to consider multiple possibilities in other experimental designs. It is only by the age of 4 years that children consistently succeed in such designs (for an overview, see [1]). How do we reconcile these findings?

The ‘minimalist theory of possibility’ (MT) [1] proposes, that designs in which humans younger than 4 years succeed do not require a modal concept of possibility (MCP). Instead, the respective tasks can be solved by simulating a single outcome (randomly chosen) which is considered as actual. If this guess turns out to be incorrect, infants/toddlers/children will generate another one. A recent study by Baumann and colleagues [2] tested predictions of the MT for 3-year-olds, finding that 3-year-olds do seem to employ MCP. To corroborate either these results or the MT, this study aims at testing the MTs predictions with a different experimental design than the one used by Baumann and colleagues.

To do so, we draw upon a phenomenon observed in the realm of word learning: If children are uncertain which out of two objects a word refers to, their uncertainty is accompanied by gaze-switches between the two objects [3].

Participants will be 20 3-year-olds. Two distinct sound-making objects will be displayed on a screen. An animated ball falls on either of the two objects, causing an object-specific sound. Children cannot see which object the ball hit; however, they can infer it based on the sound heard (condition 1). Now, if the two objects displayed on the screen are from the same kind (i.e. elicit the same sound when hit), children cannot infer where the ball landed (condition 2). The critical measure would be the number of gaze-switches between the two objects upon hearing the sound. MT would predict no difference in gaze-switches between condition 1 and 2 since in latter children randomly choose one object as the actual source of the sound. If 3-year-olds possess an MCP, their uncertainty in condition 2 should be reflected by more gaze-switches compared to condition 1.

In either case, the experiments’ results will contribute to finding an answer to the question at which age humans start to conceive of situations as being possible instead of certain or impossible.

References

[1] B. P. Leahy and S. E. Carey, “The Acquisition of Modal Concepts,” Trends in Cognitive Sciences, vol. 24, no. 1, pp. 65–78, Jan. 2020. doi: 10.1016/j.tics.2019.11.004.

[2] L. Baumann, L. P. Schidelko, M. Proft, and H. Rakoczy, “Even 3-and 4-year-olds master some modal reasoning tasks – if they have a more agentive structure,” 2025. doi: 10.31234/osf.io/5bkfa.

[3] J. Halberda, “Is this a dax which I see before me? Use of the logical argument disjunctive syllogism supports word-learning in children and adults,” Cognitive Psychology, vol. 53, no. 4, pp. 310–344, 2006. doi: 10.1016/j.cogpsych.2006.04.003.