Infantile or childhood amnesia is the phenomenon that adults have very few to no memories from their first years of life (see for overviews, Bauer, 2014; Pillemer, 1998; Rubin, 2000). Overall, a large body of research suggests that the grand average of the age reported in first memories is 3.5 years across multiple studies (Tustin & Hayne, 2010).
There is some evidence, however, that the age in earliest memories is not carved in stone. To begin with, Wang and Peterson (2014) interviewed children in various age groups (ranging from 4 to 13 years old) about their earliest memory twice, with a delay of 1–2 years between interviews. On the second interview, the same event was, on average, dated 5–7 months later. The results of a subsequent study (Wang & Peterson, 2016) assessing a subgroup of the children 8 years after the initial interview, suggested that the younger children (4–5 years old at baseline) continued to postdate the same memories. The memories were dated as having occurred more than a year later than at initial recall. Thus, dating earliest memories may fall prey to a spontaneous postdating bias (i.e., forward telescoping, Janssen, Chessa, & Murre, 2006). Furthermore, the age in earliest memories may be affected by experimental manipulations. Kingo, Bohn, and Krøjgaard (2013) examined the effects of “warm-up” retrieval. That is, prior to retrieving their very first memory, participants were instructed to recall events from when they were either 3 or 6 years old. This procedure rendered earlier first memories in the age 3 group than in the age 6 group. Likewise, Peterson, Kaasa, and Loftus (2009) found that participants who had overheard confederates talking about very early experiences reported earliest memories in which they were younger than participants who had not been exposed to social influence. In addition, Malinoski and Lynn (1999) reported that at the start of their study, 11% of their participants reported earliest memories from before the age of 2. Yet, at some time during an extensive probing procedure, 78% of the participants reported memories of such a young age.
Together, these results indicate that the age in earliest memories is malleable. This fits with the general notion that dating memories is a reconstructive activity (Friedman, 1993; Janssen et al., 2006). Unlike digital photos, memories do not contain a time-stamp (Arbuthnott & Brown, 2009). Sometimes a specific date is part of the factual knowledge (i.e., semantic memory) that is activated together with the recollective re-experiencing (i.e., episodic memory) of a particular event, such as one’s wedding day. More often, however, the “when” of a recalled event is inferred from characteristics of the memory representation (e.g., clarity, familiarity, ease of accessibility) or from context information (e.g., the distance of the retrieved event relative to a landmark event; Arbuthnott & Brown, 2009; Janssen et al., 2006). This may of course, easily result in errors (Peterson et al., 2009). Yet, the studies on dating malleability raise the intriguing possibility that earliest memories could be of an earlier age than is generally assumed in the literature on infantile amnesia (Wang & Peterson, 2014, 2016). For example, compared to the grand average of 3.5 years (Tustin & Hayne, 2010), younger average ages were obtained in the experiments reported by Kingo et al. (2013; M = 2.7 years in the complete age 3 group) and Peterson et al. (2009; M = 2.99 years in the confederate group). Perhaps the age information provided by the study context (e.g., 3 vs. 6 years old) primes participants to search for a memory within a particular life-time period (e.g., “when I was in Kindergarten” vs. “when I was in primary school”). This fits with evidence suggesting that using cues is important for obtaining relatively early memories. Tustin and Hayne (2010) used idiosyncratic timelines displaying photos of the participants at various ages ranging from new-born to current age in an ascending order. Roughly 40% of participating children (up to 12–13 years old) recalled events from before age 2, compared to 4% of adults. Jack and Hayne (2010) found that even adults can come up with memories from under age 2 when a timeline is combined with exhaustive interviewing.
Why would extensive cueing bring about earlier memories than merely asking participants for their earliest memory? The instruction to retrieve an earliest memory likely invites a strategic search in memory (i.e., generative retrieval, Conway, 2005). However, in itself such a general instruction contains few cues, and it is up to the rememberer to generate them. In general, retrieval success depends on the extent to which retrieval cues match some aspect of the memory representation (Tulving & Thomson, 1973). A detailed episodic representation will have a higher probability of being recalled, especially when it is connected to various bits of factual knowledge (i.e., semantic memory), simply because multiple types of cues will match. However, compared to later memories, early memories are impoverished in that they contain fewer narrative categories (e.g., who, where; Bauer & Larkina, 2014; West & Bauer, 1999) and that they have fewer connections with factual knowledge (Howe, 2013; Pillemer, 1998). In addition, factual knowledge may be absent or organised differently in children than adults (Conway, 2005; Howe, 2013), resulting in reduced ways of accessing early representations with further development. Thus, for older children and adults, general “describe-your-earliest-memory” instructions would elicit too few cues that overlap with too few elements in early representations for retrieval to be successful. Extensive cueing would provide more specific cues matching these sketchy memories (Pillemer, 1998). That does not mean that all early experiences could be accessed if only the right tr...
