Listen before you drive: the effect of voice familiarity on listening comprehension and driving performance.

OBJECTIVE: Voice familiarity has been reported to reduce cognitive load in complex listening environments. The extent to which the reduction in listening effort allows for mental resources to be reallocated to other complex tasks needs further investigation. We sought to answer whether a familiar audiobook narrator provides benefits to (1) listening comprehension and/or (2) driving performance. DESIGN: A double-blind between-groups design was implemented. Participants were randomly assigned to the Familiar group or the Unfamiliar group. STUDY SAMPLE: Participants (n = 30) were normal-hearing adults, 18 to 28-years-old (M = 23, SD = 2.6) (n = 18 female). Participants first listened to an audiobook read by either Voice 1 (Familiar condition) or Voice 2 (Unfamiliar condition). Then they completed a virtual reality driving task while listening to a second audiobook, always read by Voice 1. Audiobook comprehension (30-question multiple-choice test) and driving performance (number of driving errors made) were recorded. RESULTS: Participants in the Familiar group made fewer driving errors than participants in the Unfamiliar group. There were no differences in listening comprehension. CONCLUSIONS: Increased voice familiarity positively impacts behaviour (i.e. reduced driving errors) in normal-hearing adults. We discuss our findings in the context of effortful listening frameworks.

A shift in the mechanisms controlling hippocampal engram formation during brain maturation.

The ability to form precise, episodic memories develops with age, with young children only able to form gist-like memories that lack precision. The cellular and molecular events in the developing hippocampus that underlie the emergence of precise, episodic-like memory are unclear. In mice, the absence of a competitive neuronal engram allocation process in the immature hippocampus precluded the formation of sparse engrams and precise memories until the fourth postnatal week, when inhibitory circuits in the hippocampus mature. This age-dependent shift in precision of episodic-like memories involved the functional maturation of parvalbumin-expressing interneurons in subfield CA1 through assembly of extracellular perineuronal nets, which is necessary and sufficient for the onset of competitive neuronal allocation, sparse engram formation, and memory precision.