@article {2655, title = {Assessing the precision of gaze following using a stereoscopic 3D virtual reality setting.}, journal = {Vision Res}, volume = {112}, year = {2015}, month = {2015 Jul}, pages = {68-82}, abstract = {

Despite the ecological importance of gaze following, little is known about the underlying neuronal processes, which allow us to extract gaze direction from the geometric features of the eye and head of a conspecific. In order to understand the neuronal mechanisms underlying this ability, a careful description of the capacity and the limitations of gaze following at the behavioral level is needed. Previous studies of gaze following, which relied on naturalistic settings have the disadvantage of allowing only very limited control of potentially relevant visual features guiding gaze following, such as the contrast of iris and sclera, the shape of the eyelids and--in the case of photographs--they lack depth. Hence, in order to get full control of potentially relevant features we decided to study gaze following of human observers guided by the gaze of a human avatar seen stereoscopically. To this end we established a stereoscopic 3D virtual reality setup, in which we tested human subjects{\textquoteright} abilities to detect at which target a human avatar was looking at. Following the gaze of the avatar showed all the features of the gaze following of a natural person, namely a substantial degree of precision associated with a consistent pattern of systematic deviations from the target. Poor stereo vision affected performance surprisingly little (only in certain experimental conditions). Only gaze following guided by targets at larger downward eccentricities exhibited a differential effect of the presence or absence of accompanying movements of the avatar{\textquoteright}s eyelids and eyebrows.

}, keywords = {Adult, Attention, Computer Simulation, Cues, Discrimination (Psychology), Eye Movements, Eyebrows, Eyelids, Female, Humans, Judgment, Male, Middle Aged, Young Adult}, issn = {1878-5646}, doi = {10.1016/j.visres.2015.04.015}, author = {Atabaki, Artin and Marciniak, Karolina and Dicke, Peter W and Thier, Peter} } @article {389, title = {The dynamics of invariant object recognition in the human visual system.}, journal = {J Neurophysiol}, volume = {111}, year = {2014}, month = {01/2014}, pages = {91-102}, abstract = {

The human visual system can rapidly recognize objects despite transformations that alter their appearance. The precise timing of when the brain computes neural representations that are invariant to particular transformations, however, has not been mapped in humans. Here we employ magnetoencephalography decoding analysis to measure the dynamics of size- and position-invariant visual information development in the ventral visual stream. With this method we can read out the identity of objects beginning as early as 60 ms. Size- and position-invariant visual information appear around 125 ms and 150 ms, respectively, and both develop in stages, with invariance to smaller transformations arising before invariance to larger transformations. Additionally, the magnetoencephalography sensor activity localizes to neural sources that are in the most posterior occipital regions at the early decoding times and then move temporally as invariant information develops. These results provide previously unknown latencies for key stages of human-invariant object recognition, as well as new and compelling evidence for a feed-forward hierarchical model of invariant object recognition where invariance increases at each successive visual area along the ventral stream.

Corresponding Dataset - The dynamics of invariant object recognition in the human visual system.

}, keywords = {Adolescent, Adult, Evoked Potentials, Visual, Female, Humans, Male, Pattern Recognition, Visual, Reaction Time, visual cortex}, issn = {1522-1598}, doi = {10.1152/jn.00394.2013}, url = {http://jn.physiology.org/content/early/2013/09/27/jn.00394.2013.abstract}, author = {Leyla Isik and Ethan Meyers and JZ. Leibo and Tomaso Poggio} } @article {1156, title = {Short temporal asynchrony disrupts visual object recognition.}, journal = {J Vis}, volume = {14}, year = {2014}, month = {2014}, pages = {7}, abstract = {

Humans can recognize objects and scenes in a small fraction of a second. The cascade of signals underlying rapid recognition might be disrupted by temporally jittering different parts of complex objects. Here we investigated the time course over which shape information can be integrated to allow for recognition of complex objects. We presented fragments of object images in an asynchronous fashion and behaviorally evaluated categorization performance. We observed that visual recognition was significantly disrupted by asynchronies of approximately 30 ms, suggesting that spatiotemporal integration begins to break down with even small deviations from simultaneity. However, moderate temporal asynchrony did not completely obliterate recognition; in fact, integration of visual shape information persisted even with an asynchrony of 100 ms. We describe the data with a concise model based on the dynamic reduction of uncertainty about what image was presented. These results emphasize the importance of timing in visual processing and provide strong constraints for the development of dynamical models of visual shape recognition.

}, keywords = {Adult, Female, Form Perception, Humans, Male, Pattern Recognition, Visual, Psychophysics, Time Factors, Vision, Ocular, Visual Pathways, Young Adult}, issn = {1534-7362}, doi = {10.1167/14.5.7}, author = {Jedediah Singer and Gabriel Kreiman} }