Visual Processing of the Faces of Humans and Dogs by Children with Autism Spectrum Disorder: An Eye-Tracking Study

Figures & data

Table 1. Participants’ characteristics.

	NT group (n = 13)	ASD group (n = 13)	p-value
Age (years)	6.21 (1.41)	7.72 (2.36)	0.07
Gender (M/F)	3/10	10/3
Verbal level	101.69 (9.59)	93.54 (8.68)	0.09
Non-verbal level	114.69 (9.22)	108.77 (11.83)	0.21
Autistic symptoms level (CARS)		32.6 (1.8)

Note: CARS: Childhood Autism Rating Scale (Schopler et al., 1980). NT = neurotypical; ASD = autism spectrum disorder. Apart from gender, the values represent means and SDs.

Table 2. Treatments and support for children with autism spectrum disorder (n = 13)^a.

Support	n
Educational support within the school	12 children
Psychological therapy	10 children
Speech therapy	8 children
Social skills training	7 children
Involvement in a specific ASD association	6 children
Occupational therapy	2 children
Psycho-pedagogical support	1 child
Pharmacological therapy	2 children

^a Children attended multiple treatment sessions and support activities at the same time.

Figure 1. Example stimuli from the pair paradigm (from left to right): human–human, adult individual, child individual, dog individual, and human–dog pair.

Table 3. Results for individual pictures by group.

Variable	Type of stimulus	NT group mean (SD)	ASD group mean (SD)	p-value	Effect size Hedges’ g
Dwell time on the eyes (ms)	Adult faces	3,272.77 (1,587.43)	2,349.69 (2,165.03)	0.23	0.48
	Child faces	5,119.15 (2,290.48)	3,305.08 (2,179.07)	0.05	0.81
	Dog faces	6,072.23 (2,253.86)	3,683.31 (1,472.69)	0.02	1.21
Latency of first gaze point to the eyes (ms)	Adult faces	94.46 (95.25)	1,200.31 (869.04)	< 0.001	–1.73
	Child faces	1,69.61 (89.59)	937.92 (992.70)	< 0.001	–1.06
	Dog faces	148 (163.18)	384.50 (266.25)	0.13	–0.64
Average duration of continuous gaze to the eyes (ms)	Adult faces	738.83 (715.42)	395.53 (376.04)	0.14	0.58
	Child faces	976.91 (1,236.38)	376.16 (278.28)	0.10	0.65
	Dog faces	1,081.81 (793.49)	709.39 (493.33)	0.16	0.55

Note: NT = neurotypical; ASD = autism spectrum disorder.

Table 4. Pair paradigm results by group.

Variable	AOI	Type of stimulus	NT group mean (SD)	ASD group mean (SD)	p-value	Effect size Hedges’ g
Dwell time according to the side of the screen on which they appear (ms)	Full faces on the left side of the screen	Adult and dog faces	17,329.85 (4,308.81)	12,737.31 (5,109.45)	0.02	0.97
	Full faces on the right side of the screen	Adult and dog faces	11,535.46 (4,295.65)	9,771.46 (3,958.29)	0.29	0.41
Dwell time according to the type of stimuli (human or animal) (ms)	Full faces on the left and right sides of the screen	Adult faces	12,898.85 (2,993.56)	7,884.00 (4,833.66)	0.005	1.21
	Full faces on the left and right sides of the screen	Dog faces	11,783.08 (3,729.80)	12,188.08 (4,084.01)	0.79	0.08
Number of transitions between the two pictures appearing on the screen	Full faces	Adult face left – dog face right	4.54 (1.27)	3.15 (1.86)	0.63	0.84
		Dog face left – adult face right	3.46 (2.26)	3.23 (1.20)	0.75	0.12
		Adult face left and right	4.39 (1.16)	1.5 (1.17)	< 0.001	2.40
		Dog face left and right	3.61 (1.94)	4.23 (2.71)	0.51	−0.25

Note: NT = neurotypical; ASD = autism spectrum disorder. AOI = area of interest.

Figure 2. Dwell time on the area of interest of the eyes in the neurotypical (NT) and autism spectrum disorder (ASD) groups while gazing at faces of adults, children, and dogs. *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 3. Latency of the first gaze to the eyes in individual faces of adults, children, and dogs. *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 4. Average continuous gaze time on the eyes in individual faces of adults, children, and dogs. *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 5. Dwell time according to the side of the screen on which the faces appear (left or right side) and type of stimulus (human or animal) in the neurotypical (NT) and autism spectrum disorder (ASD) groups. *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 6. Total transitions between the left and right picture for pairs of stimuli (human–dog, dog–human, human–human, or dog–dog) in neurotypical (NT) and autism spectrum disorder (ASD) children. *p < 0.05, **p < 0.01, ***p < 0.001.

Schopler, E., Reichler, R. J., DeVellis, R. F., & Daly, K. (1980). Toward objective classification of childhood autism: Childhood Autism Rating Scale (CARS). Journal of Autism and Developmental Disorders, 10(1), 91–103. https://doi.org/10.1007/BF02408436

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