Skin Conductance And The Intense World
[W]e investigated the effects of gaze direction on skin conductance responses in normally developing children and in children with [high functioning] autism. [...]
Skin conductance response (SCR) refers to momentary changes in the electrical resistance of the skin reflecting the functioning of the sweat glands controlled by the sympathetic nervous system (Andreassi, 2000, pp. 193–196). Skin conductance responsiveness has been interpreted to be a sensitive method for collecting physiological data on the stimulus significance, novelty, and its’ emotional content to the subject, and it is generally believed to be a reliable accompaniment of psychological processes such as attention and orienting reflex (Dawson, Schell, & Filion, 1990). [...]
[S]kin conductance responses of high functioning children with autism and normally developing children were measured to face stimuli with straight gaze (eye contact) or averted gaze shown on a computer monitor. After the stimulus presentation, the children were asked whether the person looked straight at the child or whether the person’s gaze was averted. Hence, in this study, the children were especially asked to pay attention to the stimuli. It was expected that if eye contact with another person is associated with an unusual degree of arousal in autism, perceiving another person with a straight gaze would elicit relatively stronger skin conductance responses in comparison to an averted gaze in children with autism than in normally developing children.
Twelve school-aged children with autism took part in this study.
Frontal views of a female and a male face with a neutral expression were filmed with a video camera. The models were asked to maintain straight gaze or gaze averted to the left or right. By using the zoom of the camera, an impression was created in which the faces appeared to be looming towards the subject [...]. Moving images, particularly those which are known to be arousing, are associated with an increase in the magnitude of skin conductance responses, and they improve the viewer’s attention to stimuli (Detenber, Simons, & Bennett, 1998; Simons, Detenber, Roedema, & Reiss, 1999). As measured from the computer monitor, the inter-ocular distance of the stimulus face subtended 5° and 13° in the first and last frames of the film clip, respectively. The film clips had duration of 6 s. The facial stimuli were presented on a 20-inch computer monitor (1024Â768, 75 Hz, Apple Multiple Scan Display).
In total, 12 face stimuli were presented in a random order, 6 faces with a straight gaze and 6 faces with an averted gaze. Half of the faces were female and the other half male. The inter-stimulus-interval (ISI) was 25–35 s. After the presentation of each face (during the ISI), the children were asked whether the person they had just seen had a straight or an averted gaze direction. This confirmed that the children had to look at the face on the monitor. The children’s eye movements were also monitored using a video-camera above the computer monitor. The children were rewarded with a token after the task completion. The experimental procedure lasted around 15–20 min.
[I]n normally developing children, there was no difference in SCR between straight gaze (eye contact) and averted gaze conditions, whereas in children with autism the responses to straight gaze were stronger than those to averted gaze.
-- Anneli Kylliainen , Jari K. Hietanen
Quoted on Tue Dec 13th, 2011