Neuman et al., (1996) states that experts may have different assessments with respect to eye tracking as either an inadequate measure of brain function or as an improved measure of cognition, yet it complements brain and behavioral measures at the same time. Due to this complementation, we are able to do research on human behaviors by objectively measuring and quantifying eye movements, eye tracking is exactly such method that allows us to study human movement and thus, the method is useful to examine the autism spectrum behavior patterns. One important reason for this is that the eye tracking method includes ocular measures which provide further knowledge about accuracy and response times. Due to its high temporal resolution, it makes possible to measure moment by moment how people respond to certain tasks (Neumann & Sanders, 1996). Moreover, Eye tracking is a technology that is used in measuring a person’s point of gaze-where individual is looking-or the movement of the eye. In essence, it refers to the recording of eye movement and its relative position in an environment (Aslin, 2012). The technique is faster than any other input media, and therefore also useful for conducting usability studies as well as understanding how users interact with their environment. In relation to its speed, sampling rates of eye tracking range indicate that the faster eye trackers achieve sub-millisecond temporal resolution, just as happen in EEG method (Neumann & Sanders, 1996). Although the eye-tracking measure is an indirect measure of brain function, eye-tracking has many positive sides when we compared to EEG and fMRI. For example, participants feel comfortable during the study because they are provided suitable seating, and testing takes place in the natural environment rather than the noisy environment in contrast to the fMRI scanner. Later, the eye tracker equipment is adaptable and portable, thus, can be easily placed in a hospital or school settings. Accordingly, eye tracker provides a large amount of population for researchers. Lastly, contemporary eye trackers have fast calibration procedures thus it allows us to begin an experiment quickly. This is helpful for researchers who seek to reduce and minimize testing time (Ecksteina, Carrilloa, Singleya, & Bunge, 2017).Finally, the technique is enabling to track reflections from the corneal and assess the visual attention of an individual (Luna, Katerina, & Charles, 2008). This is one of the main reasons why Klin and colleagues used eye-tracking as a tool in their study on the interaction of children with autism, with their world and environment. Their study found out that, children with autism had attention toward sound synchronized to motion rather than social one (human movement).Moreover, contemporary eye trackers dominantly utilise the technology of visible light, which are often called infrared-free (IR-free) eye trackers. The IR illumination is generally used in hands-free interfaces as Kunkar and Kostek point out: ” In order to estimate the fixation (see Appendix B) point the eye is illuminated by infrared diode light which is invisible to the user and does not disturb his/her interaction with the computer. IR sources, appropriately installed on the camera, to generate unique reflections on the user’s eye” (Kunka & Kostek, 2009). To be more precise, the camera with relatively high-resolution has capabilities of tracking gaze positions and directions. The technology works in a such a way that the IR light is focused on the pupil of an eye resulting to reflections in the cornea which are eventually tracked by a high-resolution camera. Thus, eye tracking method can reveal the visual elements that likely attract quick attention as well as those elements that maybe be ignored and overlooked (Bryn Farnsworth, 2016).