Infants get five stars on iconic memory tests: a partial-report test of 6-month-old infants' iconic memory capacity.

By the late 19th century, tests of adults' short-term visual memory—how much one retains from a briefly presented display—had acquired a familiar character: An alphanumeric array was presented and then removed, and participants were asked to report the items they had seen (Wundt, 1912). These whole-report tests revealed memory capacities of three to four items (Cattell, 1886; Sperling, 1960). However, participants often felt that they had seen more items than they had described, but that they had forgotten those items before making their report. A crucial innovation was the partial report, in which researchers cued participants to sample from their memory (e.g., a high-pitched tone might cue a report of the middle of three rows of letters; Sperling, 1960). If the cues occurred after offset of the displays (postcues) and the sampled subsets were random, then accurate reports meant that all the presented items had been stored. This clever methodological change exposed a new early, high-capacity (about nine items), and fast-decaying (half-life of about 200 ms) memory system, dubbed iconic memory (Neisser, 1967). In a sense, the study of infants' visual memory is still rooted in the conventions of the 19th century: No one has yet asked infants for a partial report. Research on infants' visual memory has a similarly long history (e. short-term capacity has been studied only recently, and iconic memory not at all. Further, the studies on short-term capacity have revealed a striking limitation: Young infants' short-term memory capacity seems limited to a single object (see Ross-Sheehy, Oakes, & Luck, 2003, for evidence from visual short-term memory with a retention interval of less than 300 ms, and Pelphrey et al., 2004, and Kaldy & Leslie, 2005, for evidence from visual working memory). Thus, although 6-month-olds have sufficiently well-developed visual acuity to distinguish arguably dozens of objects in a single fixation (Teller, 1997), they appear to have short-term memory for only one object—a curiously inimical constraint unless this object is very well chosen (e.g., by virtue of high salience, task relevance, or cuing). We argue here that iconic memory is the buffer holding the choices, and we report an experiment that estimated its capacity. Method Sixty-two healthy, full-term, 6-month-old infants (ages 183.4 ± 20.6 days; 30 males, 32 females) each were tested in two 18-trial blocks. All the trials for a given infant involved the same set size (2, 4, 6, 8, or 10 colored stars), and approximately …