Fig 1.
(a) Introduction Phase (10 s): The female model moved to the left and then to the right twice behind the barrier. This served to make infants aware that it occluded the model. (b) Familiarization Phase (5 s): Two identical toy objects were displayed with a barrier. One of the toy objects was placed in front of the barrier, and the other was not. (c) Test Phase (20 s in total): The model stared straight ahead for 4 s accompanied by a voice saying, “Ah, Omocha-ga Aruyo! (Ah, here is a toy!).” Then, the model gazed at either the toy object that was occluded by the barrier, (Blocked Line of Sight Condition) or the toy object that was not occluded by the barrier (Clear Line of Sight Condition). The order of the Blocked Line of Sight and Clear Line of Sight Conditions was counterbalanced. Note: An eye-catcher scene was displayed before the Introduction Phase and Familiarization Phase. It was also displayed before both the Blocked Line of Sight and Clear Line of Sight Conditions in the Test Phase, respectively. This was done to direct the infants’ visual attention toward the screen.
Fig 2.
Difference score of the first saccades toward the gaze-cued toy object for the Blocked Line of Sight and Clear Line of Sight Conditions.
Results are shown for the (a) 7-month-old infants and (b) 12-month-old infants. The central mark indicates the median, and the bottom and top edges of the box indicate the 25th and 75th percentiles, respectively. The upper whisker (vertical line) extends from the third quartile to the largest value. However, this is no further than 1.5 interquartile ranges from the third quartile. The lower whisker extends from the 25th percentile down to the smallest value. This goes no further than 1.5 interquartile ranges from the first quartile. **p < 0.01.
Fig 3.
Proportion of the first looking time on the gaze-cued toy object for the Blocked Line of Sight and Clear Line of Sight Conditions.
Results are shown for the (a) 7-month-old infants and (b) 12-month-old infants. The central mark indicates the median, and the bottom and top edges of the box indicate the 25th and 75th percentiles, respectively. The upper whisker (vertical line) extends from the third quartile to the largest value. However, this was no further than the 1.5 interquartile ranges from the third quartile. The lower whisker extends from the 25th percentile down to the smallest value. However, this was no further than 1.5 interquartile ranges from the first quartile. * p < 0.05.
Fig 4.
Proportion of the total looking time on the gaze-cued toy object for the Blocked Line of Sight and Clear Line of Sight Conditions.
Results are shown for the (a) 7-month-old infants and (b) 12-month-old infants. The central mark indicates the median. The bottom and top edges of the box indicate the 25th and 75th percentiles, respectively. The upper whisker (vertical line) extends from the third quartile to the largest value. However, this was no further than 1.5 interquartile ranges from the third quartile. The lower whisker extends from the 25th percentile down to the smallest value. However, this was no further than 1.5 interquartile ranges from the first quartile.