Second, we extended previous analyses focusing on infants’ first gaze shifts, by exploring the dynamics of infants gaze movements over a longer time period, covering the entire trial time. First, our objective was to implement the eye tracking testing in a clinical environment by using automated testing and data analysis protocols. Our goal in the present study was to further develop the eye tracking based assessment of infants gaze behavior in the overlap paradigm.
However, the practice of such analyses is still complicated by several limitations that surround current eye tracking technologies and affect data quality –, and may require several verification routines to be implemented successfully in poorly co-operating participants.
Compared to other, mostly manual techniques, eye tracking has the advantage of offering the possibility for completely automated acquisition and analysis of eye movements at a high spatial and temporal resolution. Infant gaze shifts in the overlap paradigm have been analyzed by using manual scoring of eye movements from video records, by using electro-oculogram, and more recently, by using eye tracking. Sensitivity to faces and facial expressions in the overlap paradigm emerges at 5 and 7 months of age and is manifested as a delayed latency and reduced probability of gaze shifts in the context of faces, particularly when the face displays a fearful expression –. These processes undergo rapid developmental improvements during the first months of life and reach apparent stability at around six months of age,. Studies using this paradigm have typically examined the latency and/or frequency of infants gaze shift from the first (centrally presented) stimulus to the second (lateral) stimulus, putatively reflecting the active process of attention disengagement and visuospatial orienting. In the present study, our purpose was to further develop eye tracking based assessment of infant cognition in the context of the classic overlap paradigm. In this context, it is interesting to note that recent development of semi- or fully automated eye tracking systems based on infrared reflections from the cornea has provided laboratories with more objective indices of infant gaze behavior, and that these methods have been successfully used to measure infants’ visuospatial orienting, ,, and attention to the eyes or faces in complex social scenes. The endeavors to characterize the early development of attention and face preferences in infants are critically dependent on methods that i) can be successfully implemented with poorly co-operating infants of various postnatal ages, ii) enable standardized and, preferably, automated acquisition of metrics for the cognitive processes of interest, and iii) will eventually allow sufficient norms to be collected for the measures of interest to effectively characterize the performance of individual infants. In recent year, there has been increasing interest in charting the typical developmental time course of these processes in human infants –, and in deviations from the typical trajectory as a potential marker of certain neurodevelopmental disorders.
The emergence of core attention processes (e.g., visuospatial orienting) and preferential attention to social cues (e.g., faces) during the first postnatal months provide foundations for cognitive and social brain networks, and may be critical in initiating the developmental process that leads to a full repertoire of human social skills. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Ĭompeting interests: The authors have declared that no competing interests exist. The work is made available under the Creative Commons CC0 public domain dedication.įunding: This work was supported by Helsinki University Hospital, Juselius Foundation, Päivi and Sakari Sohlberg Foundation, Academy of Finland (#218284), as well as the European Community's Seventh Framework Programme (FP7-PEOPLE-2009-IOF, grant agreements #254235 and #283763).
This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. Received: OctoAccepted: ApPublished: May 20, 2014 Dichter, UNC Chapel Hill, United States of America Citation: Ahtola E, Stjerna S, Yrttiaho S, Nelson CA, Leppänen JM, Vanhatalo S (2014) Dynamic Eye Tracking Based Metrics for Infant Gaze Patterns in the Face-Distractor Competition Paradigm.