The ontogeny of long-term memory over the first year-and-a-half of life

Abstract

This research documents the development of long‐term memory in human infants from 2 months through the end of the first year‐and‐a‐half of life. In the initial study phase, we trained 6‐ to 18‐month‐old human infants in an operant task and tested them after increasing delays until they exhibited no retention for 2 successive weeks. In the second phase, their data were combined with data previously obtained from 2‐ to 6‐month‐olds in an equivalent task. The resulting function revealed that the duration of retention increases monotonically between 2 and 18 months of age. This increase was not due to age differences in original learning. This is the first systematic analysis of the course of long‐term memory across an extended period of infant development that is based on standardized parameters of training and testing. It provides a reference function against which measures of retention from infants of different ages that are obtained in different memory tasks with different parameters can be meaningfully compared. © 1998 John Wiley & Sons, Inc. Dev Psychobiol 32: 69–89, 1998

Spacing Repetitions Over Long Timescales: A Review and a Reconsolidation Explanation

“…Hsu (2010) examined how long 6-, 9-, 12-, 15-, and 18-month-old infants retained a memory for an operant task, equivalent to the mobile paradigm, when their second session was completed near the end of their time window. Comparing her data with an earlier study that used the same methodology and completed the second session 24 h after the first (Hartshorn et al, 1998a), Hsu (2010) concluded that for 6-month-old infants completing the second session near the end of the time window resulted in better retention, but for the 9- to 18-month-old infants completing the second session near the end of the time window lead to worse retention than a 24 h space. It is important to note that the 9- to 18-month-old infants successfully retrieved their memory in the second session; thus if Hsu’s (2010) conclusions are correct this calls into question the assumption that more difficult retrievals are always better as suggested by some accounts of the spacing effect (e.g., Bjork and Bjork, 1992; Delaney et al, 2010).…”

Remembering New Words: Integrating Early Memory Development into Word Learning

“…Rovee-Collier and colleagues have investigated infants’ memory retention from 2 to 18 months using the operant reinforcement paradigm (Hartshorn et al, 1998). They demonstrated that 2-month-olds show recognition of the mobile after a 1-day delay period, but not longer (Vander Linde et al, 1985).…”

“…This task also reveals a 2-week maximum retention delay for 6-month-olds (Hartshorn and Rovee-Collier, 1997). Nine-month-olds recognize the train after a delay of 6 weeks; 12-month-olds after 8 weeks; 15-month-old after 10 weeks; and 18-month-olds after 13 weeks (Hartshorn et al, 1998). …”

“…The operant conditioning paradigm uses kicking rate immediately after training as a measure of encoding, and researchers have found that this kicking rate is statistically similar for not only the majority of infants within an age group, but also across age groups (e.g., Hartshorn et al, 1998). Thus, researchers have concluded that in this task, the changes in memory retention across development are due to consolidation, not encoding (see Rovee-Collier et al, 2001).…”

Effects of viewing ordered pictorial reminders on long-term memory in the first year of life

“…Several studies have established that memory skills are fragile at the end of the first year of life, but become increasingly stable and robust as infants grow (Bauer, 2005; Bauer, Wenner, Dropik, & Wewerka, 2000; Carver & Bauer, 2001; Hartshorn et al, 1998). The main purpose of the present research was to investigate how reminders given during the post-encoding period influence memory performance in 9-month-olds as measured in a deferred imitation paradigm.…”