Hippocampal and Frontoparietal Development and Inference

Objects, faces, and scenes will be arranged into 12 ABC triads presented as overlapping AB and BC pairs. AB pairs will comprise objects; BC pairs will consist of the same B object paired with a face or scene (C). Twelve non-overlapping (NO) pairs will serve as controls. Participants will study overlapping (AB, BC) and NO pairs (4s) across two 5-minute fMRI runs. Each pair will be presented three times within a run. Following learning, participants will complete a self-paced 3-alternative forced choice (AFC) inference task during which they will select the C item that shares a common relationship with an A cue. Foils for inference trials will be C items from other ABC triads, of the same face/scene subcategory. Participants will then complete a final, self-paced 3-AFC memory test of premise associations (AB, BC) and NO pairs. To quantify memory retrieval and how overlapping events are organized, before and after learning, participants will view the A and C items during fMRI scanning.

"Participants will visit a virtual zoo, which is divided into three zones, each containing the same five monsters, but with different likelihoods of occurrence. Participants learn the underlying likelihood distributions by virtually navigating each zone. On each trial, two monsters appear; participants select the monster that they predict will next appear (6s). After making their choice, the correct monster appears and feedback is provided (2s). Participants tour each zone four times across 9 runs. Following learning, participants are tested on probabilistic inference. Here, participants see a series of monster photographs and are asked to infer in which zone they were taken. On each trial, a sequence of individual monster images (3.5s each) will then appear (1-6 monsters) prior to a decision screen, in which participants choose which of the two zones most likely produced the photos (4s) and are given feedback (1.5s). Participants will perform nine fMRI runs of the inference task."