Temporal discrimination increases in precision over development and parallels the development of numerosity discrimination

Abstract

Time perception is important for many aspects of human behavior, and a large literature documents that adults represent intervals and that their ability to discriminate temporal intervals is ratio dependent. Here we replicate a recent study by vanMarle and Wynn (2006) that used the visual habituation paradigm and demonstrated that temporal discrimination in 6-month-old infants is also ratio dependent. We further demonstrate that between 6 and 10 months of age temporal discrimination increases in precision such that by 10 months of age infants succeed at discriminating a 2:3 ratio, a ratio that 6-month-old infants were unable to discriminate. We discuss the potential implications of the fact that temporal discrimination follows the same developmental progression that has been previously observed for number discrimination in infancy (Lipton & Spelke, 2003).

Figure 1

Still images from the videos used in Experiments 1–3.

Figure 2

Mean looking time to the first three and last three habituation trials and the novel and familiar test trials for 6-month-old infants tested with a 1:2 ratio temporal discrimination in Experiment 1. Error bars indicate standard errors.

Figure 3

Mean looking time to the first three and last three habituation trials and the novel and familiar test trials for 6-month-old infants (A) and 10-month-old infants (B) tested with a 2:3 ratio temporal discrimination in Experiment 2. Error bars indicate standard errors.

Figure 4

Mean looking time to the first three and last three habituation trials and the novel and familiar test trials for 10-month-old infants tested with a 3:4 ratio temporal discrimination in Experiment 3. Error bars indicate standard errors.