A method for identifying a change in visual fixation of an individual over time during at least two sessions, the method comprising the steps of: positioning an individual in a data collection apparatus during a first session, the apparatus having a display device for displaying a stimulus to the individual and a sensor for detecting visual fixation of the individual in response to the stimulus displayed by the display device, wherein the individual is positioned in an orientation in the data collection apparatus with respect to the display device and the sensor that allows for collection of eye movement data; during the first session, causing display on the display device of a first visual stimulus to the individual; receiving first eye movement data from the sensor that indicates visual fixation of the individual with respect to the displayed first visual stimulus; positioning the individual in the data collection apparatus during a second session; during the second session, causing display on the display device of a second visual stimulus to the individual; receiving second eye movement data from the sensor that indicates visual fixation of the individual with respect to the displayed second visual stimulus; and comparing, via software executing on a processor, the first eye movement data to the second eye movement data to identify a change in visual fixation for the individual with respect to the displayed first visual stimulus and the displayed second visual stimulus, wherein the change in visual fixation for the individual is identified based on a comparison of visual fixation of the individual from the first session to the second session, wherein the change in visual fixation over time for the individual from the first session to the second session is a marker of a developmental, cognitive, social, or mental disability or ability. positioning an individual in a data collection apparatus during a first session, the apparatus having a display device for displaying a stimulus to the individual and a sensor for detecting visual fixation of the individual in response to the stimulus displayed by the display device, wherein the individual is positioned in an orientation in the data collection apparatus with respect to the display device and the sensor that allows for collection of eye movement data; during the first session, causing display on the display device of a first visual stimulus to the individual; receiving first eye movement data from the sensor that indicates visual fixation of the individual with respect to the displayed first visual stimulus; positioning the individual in the data collection apparatus during a second session; during the second session, causing display on the display device of a second visual stimulus to the individual; receiving second eye movement data from the sensor that indicates visual fixation of the individual with respect to the displayed second visual stimulus; and comparing, via software executing on a processor, the first eye movement data to the second eye movement data to identify a change in visual fixation for the individual with respect to the displayed first visual stimulus and the displayed second visual stimulus, wherein the change in visual fixation for the individual is identified based on a comparison of visual fixation of the individual from the first session to the second session, wherein the change in visual fixation over time for the individual from the first session to the second session is a marker of a developmental, cognitive, social, or mental disability or ability.