Infants' reasoning about hidden objects: evidence for event-general and event-specific expectations

Abstract

Research over the past 20 years has revealed that even very young infants possess expectations about physical events, and that these expectations undergo significant developments during the first year of life. In this article, I first review some of this research, focusing on infants' expectations about occlusion, containment, and covering events, all of which involve hidden objects. Next, I present an account of infants' physical reasoning that integrates these various findings, and describe new experiments that test predictions from this account. Finally, because all of the research I discuss uses the violation-of-expectation method, I address recent concerns about this method and summarize new findings that help alleviate these concerns.

Figure 1

Occlusion violations detected by 2.5-month-old infants: row 1, Spelke et al. (1992); row 2, Wilcox et al. (1996); row 3: Aguiar and Baillargeon (1999).

Figure 2

Top two rows: containment violations detected by 2.5-month-old infants, Hespos and Baillargeon (2001b); bottom two rows: covering violations detected by 2.5- to 3-month-old infants, Wang et al. (in press).

Figure 3

Habituation and test events used by Aguiar and Baillargeon (2002); the screen was lowered at the start of each trial to reveal either one mouse (3.5-month-old infants) or two mice (3-month-old infants).

Figure 4

Habituation and test events used by Aguiar and Baillargeon (2002) with 3- and 3.5-month-old infants; the screen was lowered at the start of each trial to reveal one mouse and one small screen large enough to hide a second mouse.

Figure 5

Sequence of variables infants identify as they learn when an object behind an occluder should and should not be hidden.

Figure 6

Familiarization and test events used by Luo and Baillargeon (in press).

Figure 7

Test events used by Hespos and Baillargeon (2001a) in the containment, occlusion and container-as-occluder conditions.

Figure 8

Top two rows: décalage in infants’ reasoning about height in containment and covering events (Wang et al., in press); bottom two rows: décalage in infants’ reasoning about transparency in occlusion and containment events (Luo & Baillargeon, 2004a, 2004b).

Figure 9

Schematic representation of the reasoning account (Baillargeon, 2002; Wang et al., in press).

Figure 10

Test events used by Wang and Baillargeon (2004a) in the covering and occlusion conditions.

Figure 11

Teaching and test events used by Wang and Baillargeon (2004c).

Figure 12

Teaching events used by Wang and Baillargeon (2004c) in the short-object, no-height-comparison and shallow-cover experiments.

Figure 13

Test events used by Wang et al. (2004) in the experimental and control conditions.

Figure 14

Familiarization and test events used by Baillargeon and Graber (1987).

Figure 15

Familiarization and test events used by Luo et al. (2003).