What Makes a Birdbrain Tick: Long-term Memory Drives Expertise Effects on Working Memory Binding

Considerable research concerning the multidirectionality of cognitive aging indicates that retrieving factual knowledge from semantic long-term memory (LTM) remains stable in healthy older age despite declines in actively maintaining information in working memory (WM). This study addressed how older adults’ extensive acquired knowledge may support WM by mitigating age deficits in the speed of establishing bindings in WM (Block 1) or through greater contributions from LTM (Block 2). Younger novices (N = 38; Mage = 23.63, SD = 5.49), older novices (N = 56; Mage = 69.55, SD = 5.48), and older experts (N = 26; Mage = 66.96, SD = 5.41) in birding completed two blocks of a WM binding task that presented images of birds paired with words (e.g., robin-mudflat; pigeon-quick) for an immediate test of each bird (e.g., robin) with three options: the target (e.g., mudflat), a lure from the trial but not paired with that bird (e.g., quick), and a new-to-block distractor. Block 1 showed that older experts were just as slow as older novices when adapting the presentation rate of the pairs to achieve similar accuracy performance, regardless of the expertise-relevance of the stimuli (i.e., intact normal birds versus scrambled meaningless birds). However, in Block 2, older experts exhibited an advantage to model parameter estimates of binding memory, but only when LTM was reliable (i.e., under no but not high proactive interference). Thus, rather than faster WM binding, expertise in healthy older age may confer benefits by outsourcing the demands of WM storage to LTM.