Infant studies
Transfer across depth cues
Is there a representation in the developing human brain that allows children to go from one type of depth cue to another, not only as they experience it perceptually, but also as they transfer from one type of depth information to another?
- shading
- surface contours
- bulge or dent
Transfer across pictorial depth cues:
It has been well documented that infants are interested in novel stimuli, i.e., things that are new. We showed 4-7 month old infants a series of images from the four above. Shading and surface-contour cues are pictorial information of the depth of an object. We presented matching pair of either surface-contour or shading cue images with either the center ring being concave or convex to the infants for a period of time so that they would become habituated to the shape. Then we presented another pair of mismatching concave-convex images of the opposing pictorial cue, i.e., if habituation began with a pair of shading cue images, the test trial would follow with a pair of surface-contour cue images. Since we knew that infants preferentially look at novel stimuli, we therefore expected infants to spend more time looking at whichever type of test image, either concave or convex, that wasn’t the same type that they had previously seen. The real question was whether this effect would be observed across pictorial depth cues. The results indicated that 4-5 month old infants did not transfer pictorial depth cues, but that 6-7 month old infants preferentially looked at the novel stimulus, even as it appeared through a new pictorial cue.
Transfer #2:
Transfer #3:
Transfer #4:
Generic Viewpoint Assumption
The “generic viewpoint” theory suggests that when there is a lack of visual information given to us, our brains tend to make assumptions on what were seeing based on our previous interactions with the world around us. In the top picture to the left, it looks as if there is one square closer to you as the viewer, overlapping the square in the background. While it is possible something else is going on, your brain makes this assumption based on your past interactions with your environment. It is possible, of course, that the two shapes are really a square and 'pac-man' perfectly lined up (middle image)to create the top image, but this coincidence is not likely in your everyday environment. It is much more likely that when the shapes are pulled apart, the top image would become two complete squares. Therefore, your brain takes this “generic” or “non-accidental” viewpoint when you are given little information. We want to know at what age infants begin to use this assumption about objects.
Lightness Constancy
Information Coming Soon!
Wire Cube Illusion
Display from infant's viewpoint.
We believe that one aspect of perceptual learning and development consists of the creation and use of representations or models. These representations are stimulated or recognized by input from early visual processes. These representations or models, a cube for example, provides top-down information to an earlier stage in vision, and functions like a hypothesis that is tested against input. If the data matches the hypothesis, then we experience a 3-D cube when only 2-D contours of a cube are presented to the retina (see Figure A). Our question is, when do infants begin to form and use such hypotheses?
To explore the development of this process we constructed a wire half cube and presented it with the vertex pointed away from 22 7-month-old infants. We observed the reaching behavior of the infants when they viewed the display with one eye covered and with two eyes. The vertex of the display appears closer than the outer edges when the real display is viewed with one eye, but when viewed with both eyes the actual layout is perceived.
See the video from YouTube:
Inverted Face Illusion
Same as the wire cube but with a face instead.
Future projects
Horizontal-Vertical Illusory Contours
This is the study about how infants perceive lightness and darkness.
Visual Balance Beam
Infants very shortly after birth show a walking reflex in that, if their feet touch the ground, they will produce a walking-like movement. We are interested in the constraints of this behavior. Do infants walk in a straight line? We plan to place infants on a solid surface in which it looks as if only a balance beam is beneath them (they will be fully supported). We then plan to measure whether or not the infant walks in a straight line as compared to when they are on a continuous surface.
Looming in Baby Monkeys
Information coming soon!
Familiar Size
We are interested in whether or not infants respond to a pictorial depth cue called familiar size. At what point do infants’ knowledge of the size of faces begin to influence their responses to faces in terms of depth. We plan to present infants with faces of various sizes and measure looking responses to these faces to see if infants are sensitive to familiar size cues.
Guided Hallucination
Information coming soon!