Thus, the computational analysis suggested that the task was to remember that something existed even when it is out of sight (see for discussion McClelland et al., 2010; Smith & Thelen, 2003; Thelen & Smith, 1994), and the behavioral change was explained at the algorithmic and representational level in terms of a deficit in cognitive processing. Ten- month-old infants, who make the error reliably, were said to lack a specific representation called the “object concept” (Piaget, 1954) and did not understand that the object contin- ued to exist after it was hidden. In contrast, 12-month-old infants, who are typically able to search correctly, were said to represent the object mentally even when it was not visu- ally available.