We thank Iris van Rooij, Sam Forbes and Brad Wyble for helpful comments on a previous draft of this manuscript.
The unequal variance signal detection (UVSD) model of recognition memory assumes that the variance of old item memory strength (σ<sub>o</sub>) is typically greater than that of new items. It has been suggested that this <i>old item variance effect</i> can be explained by the encoding variability hypothesis. However, Spanton and Berry (2020) failed to find evidence for this account, suggesting that σ<sub>o</sub> may simply scale with mean memory strength (<i>d</i>) in the UVSD model. Experiments 1 and 2 examined the effects of encoding variability and strength scaling on old item variance by creating conditions in which mean memory strength and variability in item characteristics was either low or high in 2 × 2 factorial designs. In Experiment 1, overall strength determined estimates of σ<sub>o</sub>, with no effect of item characteristic variability. The same effect of overall strength was found in Experiment 2; there was also a significant effect of item characteristic variability, although this manipulation also had some effect on <i>d</i> and was therefore partially confounded. Experiment 3 similarly found a simultaneous increase in old item variance and memory strength in a design using mixed item characteristic variability conditions in a single study/test block. We conclude that old item variance increases with mean memory strength in the UVSD model, with uncertainty about the effects of encoding variability, and that future explanations of the old item variance effect should bear this in mind.
The unequal variance signal detection (UVSD) model of recognition memory assumes that the variance of memory strength for studied items (σo) is typically greater than that of non-studied items. It has been proposed that this old item variance effect is caused by many factors that affect memory strength at encoding, which add variable amounts of strength to a baseline amount. However, Spanton and Berry (2020) failed to find evidence for this encoding variability hypothesis and instead found that estimates of σo tended to be strongly positively correlated with estimates of mean memory strength (d) across participants, suggesting that σo may simply scale with d. The present experiments examined the effects of encoding variability and scaling on old item variance by creating conditions in which mean memory strength and encoding variability was either low or high in 2 × 2 factorial designs. In Experiment 1, overall strength determined estimates of σo, with no effect of encoding variability. The same effect of overall strength was found in Experiment 2; there was also a significant effect of encoding variability, although this manipulation also affected overall memory strength and was therefore partially confounded. We conclude that there is strong evidence that mean memory strength at least partially determines estimates of old item variance, and that satisfactory explanations of the old item variance effect should account for this.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.