Most previous studies on time perception have examinedtemporal order and distance judgments in isolation usingcontrolled stimuli. However, in real life, these two elementarytemporal experiences are related. Here, we examine the effectsof age and event structure on temporal estimation and introducea novel timeline estimation paradigm comprising temporalorder and distance judgments with naturalistic stimuli. In twoexperiments, we asked participants to view a three-minute-longvideo clip and mark the temporal order and distance of aspecific scene of the video on a horizontal timeline. In the firstexperiment, we conducted the timeline estimation task withthree different age groups – 6-8-year-olds, 9-11-year-olds andadults – and found age-related differences in the participants’accuracy and variability of temporal estimation. Thenonlinearity between their estimates and stimulus distancedecreased as their ages increased. In Experiment 2, we testedthe effect of event structure on participants’ timeline estimationand observed that more complicated video resulted in moredistorted temporal estimation. In sum, the current studycorroborated the timeline estimation task to be a valuable toolfor assessing temporal judgments across development.

The overlap of numerical and non-numerical properties in concrete object arrays raises the question of how these input dimensions interact. Two studies were conducted to address this question and showed that changing the object identity (while retaining the numerosity) and changing the numerosity (while retaining the object identity) both resulted in attenuated recognition of object arrays. However, this interference differed across development. In adults interference was asymmetrical (i.e. changing the object identity has greater effect on memory for numerosity than changed numerosity had on object identity). In contrast, children showed a symmetrical pattern of interference. These results imply that for adults, processing numerosity might be an attention-demanding process compared to a spontaneous object perception. Children, however, processed neither the object identity nor numerosity independently.

We explore potential cross-informant discrepancies between child- and parent-report measures with an example of the Child Behavior Checklist (CBCL) and the Youth Self Report (YSR), parent- and self-report measures on children's behavioral and emotional problems. We propose a new way of examining the parent- and child-report differences with an interaction map estimated using a Latent Space Item Response Model (LSIRM). The interaction map enables the investigation of the dependency between items, between respondents, and between items and respondents, which is not possible with the conventional approach. The LSIRM captures the differential positions of items and respondents in the latent spaces for CBCL and YSR and identifies the relationships between each respondent and item according to their dependent structures. The results suggest that the analysis of item response in the latent space using the LSIRM is beneficial in uncovering the differential structures embedded in the response data obtained from different perspectives in children and their parents. This study also argues that the differential hidden structures of children and parents' responses should be taken together to evaluate children's behavioral problems.