title: The eye of the retriever: developing episodic memory mechanisms in preverbal infants assessed through pupil dilation.
abstract: Studying memory in infants can be challenging, as they cannot express their subjective recollection verbally. In this study we use a novel method with which we can assess episodic recognition memory through pupillometry, using identical procedures and stimuli for infants and adults. In three experiments of 4- and 7-month-old infants, and adults we show that the adult pupillary response is larger to previously seen than to never seen items (old/new effect). Pupil dilations index subjective memory experience in adults, producing distinct pupil dilations to items judged as remembered, familiar, and new, regardless of actual previous exposure (Experiment 1). Seven-month-old infants demonstrate a clear pupillary old/new effect, very similar to that of adults (Experiment 2), whereas 4-month-olds do not demonstrate such an effect (Experiment 3). Our findings suggest that the mnemonic mechanisms that serve infants' and adults' episodic recognition memory are more similar than previously asserted: they are not fully developed at 4 months of age but that there is contiguity in human episodic memory development from 7 months of age.
authors.affiliation: Uppsala Child and Baby Lab, Department of Psychology, Uppsala University, Uppsala, Sweden.
authors.forename: Kahl
authors.initials: K
authors.lastname: Hellmer
authors.affiliation: Uppsala Memory Lab, Department of Psychology, Uppsala University, Uppsala, Sweden.
authors.forename: Hedvig
authors.initials: H
authors.lastname: Söderlund
authors.affiliation: Uppsala Child and Baby Lab, Department of Psychology, Uppsala University, Uppsala, Sweden.
authors.forename: Gustaf
authors.initials: G
authors.lastname: Gredebäck
mesh_terms: D000328:Adult; D000367:Age Factors; D004106:Dilatation; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D061212:Memory, Episodic; D011939:Mental Recall / Q000502:physiology; D011680:Pupil / Q000502:physiology*; D021641:Recognition, Psychology / Q000502:physiology*