Separate Cognitive Mechanisms Limit Episodic Future Thinking in 3- and 4-year-olds

• In Event: 2-214 - Mechanisms Supporting the Development of Future-oriented Thinking

Integrative Statement

Episodic future thinking (EFT) involves sampling episodic memories in anticipation of future events. EFT involves at least two processes - retrieving relevant episodic memories and using these in service of a goal - but little is known about the development of these processes. Across two experiments, we investigated 3- and 4-year-olds using a task designed to tease apart episodic memory and planning, to elucidate sources of developmental change in early EFT.

Both experiments had two phases: Episodic Memory Formation and EFT Test. During Episodic Memory Formation, we familiarized children to a box with four transparent drawers embedded in its front, and demonstrated that the drawers could be opened by performing four unique actions. We then showed children two animals, Monkey and Lion who each had a favorite color (yellow or red). In four demonstrations, we baited a drawer with a red or yellow bead, and children were asked which action to take to retrieve the bead.

Children then completed six EFT Test trials. In Experiment 1 (n=32; 16 3-year-olds (M = 41.08, SD = 3.27) and 16 4-year-olds (M = 53.33, SD = 4.38; 7 girls)), we baited the drawers with two beads (1 red, 1 yellow). Children were told that Monkey and Lion were going to take turns, and were asked to retrieve beads for both animals in a specific order (e.g., Monkey, then Lion; color was not mentioned during Test; see Figure 1 for wording). Critically, this task engaged two EFT processes: children had to retrieve episodes acquired during Episodic Memory Formation (i.e., action/drawer associations) and deploy this information to acquire the bead(s) in the correct order. We reasoned that, if children could effectively engage both processes, they should take the correct actions in the correct order. If children could retrieve the relevant memories, but had more difficulty with deploying them in the correct order, they should make “swap” errors. If children had difficulty with both processes, they should engage in “subset” responses (i.e. taking only one of the correct actions) or perform randomly (“error”). Children’s responses are depicted in Figure 2. While 4-year-olds outperformed 3-year-olds, both age groups selected the correct series of actions at rates significantly above chance (p<0.001), and made relatively few errors.

In Experiment 2 (n=32; 16 3-year-olds (M = 41.94, SD = 2.54); 16 4-year-olds (M = 53.34, SD = 3.37)), we examined limits on these processes. EFT Test trials proceeded as in Experiment 1, except that we manipulated Set Size by baiting drawers with 2, 3, or 4 objects (4 trials each, blocked). Children’s correct responses remained above chance for each set size (all ps<0.001), but declined as set size increased (p<0.001). Critically, swaps increased with set size (p<0.001), suggesting children were able to retrieve the relevant episodes, but had more difficulty planning their order. Three-year-olds were more likely than 4-year-olds to engage in subset responses (p<0.05).

These results suggest that EFT development may be driven by both processes, but that planning processes may impose greater limits than retrieval.

Authors

• Tashauna Blankenship, Boston University
  Presenting Author

• Melissa M. Kibbe, Boston University
  Non-Presenting Author