One-year old infants control bottom-up saliencies to purposely sustain attention

Abstract

Salient stimuli attract gaze [1,2]. Mature perceivers internally suppress salient distractors to purposefully sustain attention on a visual target. Infants’ abilities to purposefully sustain gaze on an object, often measured in the context of play, is also assumed to require the internal suppression of distractors and is considered an early marker and risk point in the development of the internal regulatory processes mediated by the pre-frontal cortex [3,4]. Here we show that sustained attention by one-year-old infants includes a behavior-driven increase in the external salience of the target. Using head-mounted eye trackers, we measured infants’ gaze during object play and the momentary visual size of objects in the infant’s field of view. Visual size is well-known to robustly attract gaze [1]. We found that when infants directed gaze to an object, there was a simultaneous change in the the spatial relation of the head to the attended object increasing the target’s visual size relative to distractors. The onset, duration, and offset of the increased salience was time-locked with the onset, duration and offset of infant gaze to the object. The findings challenge characterizations of infant attention as a competition between bottom-up and top-down control and implicate instead a collaboration in which top-down goals drive infant’s externally-directed behaviors that suppress the salience of distractors at input. The top-down control of attention through externally directed behavior may serve as the training ground –and risk factor – in the development of internal control.

The neural and physiological substrates of real-world attention change across development.

“…With time, we seem to observe a higher-level control of attention that allowed older infants to prioritize the task at handlearning about/ exploring the toysas well as to inhibit the tendency to shift attention away from an interesting task (6,20,25). Alternatively, longer attention episodes might arise because children physically manipulate objects, bringing objects closer to themselves which makes them more exogenously salient (37,59). In this case, then the infant's increased looking behaviour would be the result of increased exogenous attentional capture rather than an increase in endogenous attention control (46).…”

“…EEG data was pre-processed and cleaned from oculomotor and other contaminatory artefacts using a fully automatic artefact rejection procedure specially designed for naturalistic infant EEG data by Mariott Haresign (66), building on previous related work (59,60). Briefly, this involved the following steps: 1) data were high-pass filtered at 1Hz, 2) line noise at 50Hz was eliminated using the EEGLAB function clean_line.m, 3) data were low-pass filtered at 20Hz, 4) the data were referenced to a robust average reference 5) noisy channels were rejected using the EEGLAB function pop_rejchan.m, 6) the channels identified in the previous stage were then interpolated back, using the EEGLAB function eeg_interp.m, 7) continuous data were automatically rejected (NaN-ed) in a sliding 1s epoch based on a percentage of bad channels (set here at 70% of channels) that exceed 5 standard deviations of the mean channel EEG power, and 8) Independent Component Analyses (ICA) were computed on the continuous data using the EEGLAB function runica.m.…”

The neural and physiological substrates of real-world attention change across development.

“…With time, we seem to observe a higher-level control of attention that allowed older infants to prioritize the task at handlearning about/ exploring the toysas well as to inhibit the tendency to shift attention away from an interesting task (6,20,25). Alternatively, longer attention episodes might arise because children physically manipulate objects, bringing objects closer to themselves which makes them more exogenously salient (35,53). In this case, then the infant's increased looking behaviour would be the result of increased exogenous attentional capture rather than an increase in endogenous attention control (39).…”

The neural and physiological substrates of real-world attention change across development.

“…With time, we seem to observe a higherlevel control of attention that allowed older infants to prioritize the task at hand -learning about/ exploring the toys -as well as to inhibit the tendency to shift attention away from an interesting task (Colombo, 2001 ;Courage et al, 2006 ;Oakes et al, 2002 ). Alternatively, longer attention episodes might arise because children physically manipulate objects, bringing objects closer to themselves which makes them more exogenously salient (E. M. Anderson et al, 2022 ;Méndez et al, 2021 ). In this case, then the infant's increased looking behaviour would be the result of increased exogenous attentional capture rather than an increase in endogenous attention control .…”