Look more carefully: Even your data show sleep makes memories more accessible. A reply to Schreiner and Rasch (2018)

Memory quality modulates the effect of aging on memory consolidation during sleep: Reduced maintenance but intact gain

“…Meeting the long demand to go beyond average net measures of memory (Tulving 1964(Tulving , 1967, we separated different consolidation mechanisms based on the encoding quality of the respective memory (Dumay 2016;Fenn and Hambrick 2013). Our results are in line with ongoing discussions in the field, suggesting that the major role of sleep can be seen in the maintenance rather than the gain of memories (Dumay 2018;Fenn and Hambrick 2013;Nettersheim et al 2015;Schreiner et al 2018; but see Walker 2005).…”

“…By looking at each memory's individual "fate" it becomes possible to identify whether and how the success of memory encoding influences later consolidation processes (Dumay 2016;Fenn and Hambrick 2013): sleep potentially stabilizes previously successfully encoded memories but may also enhance the availability of initially poor memories above a pre-sleep learning level (Ellenbogen et al 2006;Nettersheim et al 2015). So far, prevailing evidence speaks for a primary role of sleep in memory maintenance: by passively protecting memories against interference (Wixted, 2004) and actively reactivating and stabilizing memory engrams (Rasch et al 2007), memories are maintained across sleep (Dumay 2018;Fenn and Hambrick 2013;Schreiner et al 2018). Behaviorally observed memory gains that reflect the availability of initially poor memories during later memory retrieval appear to rely less on sleep (Dumay 2018;Fenn and Hambrick 2013;Schreiner et al 2018).…”

“…So far, prevailing evidence speaks for a primary role of sleep in memory maintenance: by passively protecting memories against interference (Wixted, 2004) and actively reactivating and stabilizing memory engrams (Rasch et al 2007), memories are maintained across sleep (Dumay 2018;Fenn and Hambrick 2013;Schreiner et al 2018). Behaviorally observed memory gains that reflect the availability of initially poor memories during later memory retrieval appear to rely less on sleep (Dumay 2018;Fenn and Hambrick 2013;Schreiner et al 2018).…”

Electrophysiological Indicators of Sleep-associated Memory Consolidation in 5- to 6-Year-Old Children

“…Depending on the quality of a memory, the outcomes and underlying processes of memory consolidation might differ. That is either the maintenance of memories already accessible prior to sleep or the gain of items previously not consciously available (Dumay, 2016(Dumay, , 2018Fenn & Hambrick, 2013). Several studies indicated that sleep-associated system consolidation mechanisms preferentially act on the maintenance of memories of weak to intermediate quality (Denis et al, 2020;Drosopoulos et al, 2007;Fenn & Hambrick, 2013;Schapiro et al, 2018;Schreiner & Rasch, 2018;Wilhelm et al, 2012; but see Schoch et al, 2017;Tucker & Fishbein, 2008).…”

“…Another source of inconsistencies across studies may result from ignoring the encoding strength of individual memories (i.e., memory quality; Craik & Lockhart, 1972; Tulving, 1967) prior to sleep (Muehlroth et al, 2020; Wilhelm et al, 2012, 2020). Memory quality has been suggested to impact the underlying processes of memory consolidation and their subsequent outcomes — that is, either memories already accessible prior to sleep are maintained or items previously not consciously available are gained (Dumay, 2016, 2018; Fenn & Hambrick, 2013). Several studies have indicated that sleep-associated system consolidation mechanisms preferentially act on the maintenance of memories from weak to intermediate quality (Denis et al, 2020; Drosopoulos et al, 2007; Fenn & Hambrick, 2013; Muehlroth et al, 2020; Schapiro et al, 2018; Schreiner & Rasch, 2018; Wilhelm et al, 2012; but see Schoch et al, 2017; Tucker & Fishbein, 2008).…”