Proactive interference and the development of working memory

Abstract

Working memory (WM), the ability to maintain information in service to a task, is characterized by its limited capacity. Several influential models attribute this limitation in a large extent to proactive interference (PI), the phenomenon that previously encoded, now-irrelevant information competes with relevant information. Here, we look back at the adult PI literature, spanning over 60 years, as well as recent results linking the ability to cope with PI to WM capacity. In early development, WM capacity is even more limited, yet an accounting for the role of PI has been lacking. Our Focus Article aims to address this through an integrative account: since PI resolution is mediated by networks involving the frontal cortex (particularly, the left inferior frontal gyrus) and the posterior parietal cortex, and since children have protracted development and less recruitment of these areas, the increase in the ability to cope with PI is a major factor underlying the increase in WM capacity in early development. Given this, we suggest that future research should focus on mechanistic studies of PI resolution in children. Finally, we note a crucial methodological implication: typical WM paradigms repeat stimuli from trial-to-trial, facilitating, inadvertently, PI and reducing performance; we may be fundamentally underestimating children's WM capacity. This article is categorized under: Psychology > Memory Neuroscience > Cognition Neuroscience > Development.

Keywords: capacity; cognitive control; development; interference; working memory.

Figure 1.

The results of Kane & Engle (2000) show the difference in words recalled across lists in the no-load condition and high-load conditions among high-span vs. low-span individuals. The bar graphs show the PI effect in the two groups of individuals demonstrating that the low-span individuals’ ability to cope with PI does not differ significantly when attentional load is increased.

Figure 2.

Results of Endress and Potter (2014) showing large visual WM capacity estimates in conditions with unique relative to repeated stimuli. Strikingly, participants were able to correctly remember 30 out of 100 unique items (Experiment 3).

Figure 3.

Brain areas involved in PI resolution: IFG (inferior frontal gyrus, or mid-ventrolateral prefrontal cortex, vlPFC), pre-SMA (pre-supplementary motor area), dlPFC (dorsolateral prefrontal cortex), PPC (posterior parietal cortex), areas in the MTL (medial-temporal lobe). MTL is in lighter color to indicate its medial position (not visible in this lateral view).

Figure 4.

Results of Kail (2002). 9- to 12-year-old children and young adults were tested in four trials of a Brown-Peterson task. The effect of proactive interference decreased with age.

Figure 5.

Forest plot depicting effect sizes (Hedges g) in our meta-analysis (5 articles, 15 studies, 401 infant participants) testing the difference between (baseline-corrected) Trial 1 and Trial 3 performance. Overall effect size is 0.37, p = 0.0002