Memory resources recover gradually over time: The effects of word-frequency, presentation rate and list-composition on binding errors and mnemonic precision in source memory

Abstract

Normative word frequency has played a key role in the study of human memory, but there is little agreement as to the mechanism responsible for its effects. To determine whether word frequency affects binding probability or memory precision, we examined working memory for spatial positions of words. Each of three experiments included 300 trials in which five words were presented sequentially around an invisible circle followed by one of those words shown in the middle of the circle as a probe to test its location. Participants had to click on the associated location and the degree of error around the circle was the dependent measure. Across experiments we varied word frequency, presentation rate and the proportion of low frequency words on each trial. A mixture model dissociated memory precision, binding failure and guessing rates from the continuous distribution of errors. On trials that contained only low- or high-frequency words, low-frequency words lead to a greater degree of error in recalling the associated location. This was due to a higher word-location binding failure and not due to differences in memory precision or guessing rates. Slowing down the presentation rate eliminated the word frequency effect by reducing binding failures for low-frequency words. Mixing frequencies in a single trial hurt high-frequency and helped low-frequency words, but frequency composition and presentation rate did not interact. These findings support the idea that low-frequency words require more resources for binding and that the binding fails when these resources are insufficient.

Frequency effects on memory: A resource-limited theory.

“…Recall accuracy is highest in lists composed of 100% HF items, medium in lists composed of 75% HF items, and lowest in lists composed of 25% HF items (DeLosh & McDaniel, 1996). Similar results hold with word recognition, where the discrimination between LF targets and foils improves as the proportion of HF words on the list increases (Malmberg & Murnane, 2002), and with source memory, where the ability to recall the spatial position of LF cues improves as the proportion of HF words on the list increases (Popov et al, 2019). In SAC, the reduced probability of storing LF items on mixed lists is due to the fact that storing HF words depletes fewer resources, and as a result, the greater the proportion of HF words on the list, the more resources remain to process the LF words.…”

“…Results show that is easier to store the study context for items that have preexisting representations (e.g., better recognition when the scene in is reinstated for famous but not non-famous faces, Reder et al, 2013), for items rated as more familiar (DeWitt et al, 2012), and for HF compared to LF words in pure (Popov, So, & Reder, 2019), but not in mixed lists (Osth, Fox, McKague, Heathcote, & Dennis, 2018). According to our theory, the processing of an unknown face (Reder et al, 2013), a LF word (Popov et al, 2019) or a less familiar item (DeWitt et al, 2012) consumes the available WM resources to build a long-term representation, so there are fewer resources available for forming a link between the item representation and the context in which they appear. Furthermore, consistent with the resource depletion explanation, Popov et al (2019) found that slowing down the presentation rate from 500ms to 750ms to 1000ms linearly decreases the difference in source memory between LF and HF trials.…”

“… Better source memory for more familiar items, but the effect disappears when attention is divided during item encoding (DeWitt et al, 2012).  Better source memory for HF words in pure lists, but the effect is reduced with longer study times (Popov et al, 2019).…”

“…The difference between their verbal account and SAC is that SAC proposes a more general resource depletion mechanism -depleting more resources for LF items leaves fewer resources for processing subsequent items rather than for processing the order of items per se. This difference allows SAC to explain why the mixed-list paradox appears in recognition (Malmberg & Murnane, 2002) or source memory (Popov et al, 2019), wherein memory decisions for individual items do not benefit from remembering the order in which items appeared during study.…”

Frequency effects in recognition and recall

“…This is not due to floor effects -when we consider the false alarm rates in these experiments, recognition performance remains well above chance even with the fastest presentation times (d'250ms = 0.88 in Nelson, 2003 andd'150ms = 0.58 in Criss &McClelland, 2006). In general, reducing study time tends to hurt performance for LF words more than it does for HF words (also see, Criss & Shiffrin, 2004), and this pattern also holds for other tasks such as source memory (Popov, So, & Reder, 2019). This decrease in hits, as a function of a decrease in study time for LF words, is manifest entirely in fewer remember responses (Figure 3) -the proportion of know responses to LF words does not change as a function of study time (Hirshman et al, 2002).…”