Abstract
The development of long-term event memory in preverbal infants remains elusive. To address this issue, we applied an eye-tracking method that successfully revealed in great apes that they have long-term memory of single events. Six-, 12-, 18- and 24-month-old infants watched a video story in which an aggressive ape-looking character came out from one of two identical doors. While viewing the same video again 24 hours later, 18- and 24-month-old infants anticipatorily looked at the door where the character would show up before it actually came out, but 6- and 12-month-old infants did not. Next, 12-, 18- and 24-month-old infants watched a different video story, in which a human grabbed one of two objects to hit back at the character. In their second viewing after a 24-hour delay, 18- and 24-month-old infants increased viewing time on the objects before the character grabbed one. In this viewing, 24-month-old infants preferentially looked at the object that the human had used, but 18-month-old infants did not show such preference. Our results show that infants at 18 months of age have developed long-term event memory, an ability to encode and retrieve a one-time event and this ability is elaborated thereafter.
Highlights
Kano and Hirata[13] recently invented a novel eye-tracking method to investigate long-term memory of one-time events in non-verbal great apes
Identical movies were presented to the great apes twice, with an interval of 24 hours and their eye movements were compared across the two presentations
The present study examined the anticipatory looking behaviour of preverbal infants toward events that they encountered only once, 24 hours earlier
Summary
Kano and Hirata[13] recently invented a novel eye-tracking method to investigate long-term memory of one-time events in non-verbal great apes. The results revealed that great apes make anticipatory looks at locations or objects related to future events based on the long-term memory of a previous single experience. Because infants around 6 months of age have already exhibited anticipatory looking behaviour[14,15], this paradigm is appropriate for examining an ability of long-term event memory in non-verbal animals and in preverbal human infants. The present study, utilized the same video stimuli and paradigm as that in the great apes study for a wide age range of preverbal infants to investigate the developmental process of long-term memory of a one-time event. To dissociate object memory from location memory, we had half of the infants for each age group view the same movie but with the object location switched on the second day
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
