Published January 12, 2017
What happens when two objects are filled in in the blind spot, but the resulting percepts contradict each other? As in many other ambiguous situations, you perceive rivalry! This new paper by Mandy Chen, together with Gerrit, David Whitney from Berkeley and Rachel Denison at NYU shows how.
The paper also includes the cool new Jumping Pen Illusion. Try it out for yourself!
The jumping pen illusion, a demonstration of filling-in rivalry. (A) Step 1: Use a strip of paper with a fixation cross and a blind spot indicator (red circle) to find your blind spot. With the cross on the left, close your left eye, fixate the cross, and move the strip toward or away from you until the red circle disappears. (B) Step 2: While keeping the blind spot indicator in your blind spot, take a pen and hold it vertically behind the card. Slide the pen behind the card into your blind spot. The pen may appear to jump in front of the strip. When the pen and strip are held in fixed positions, the pen and strip can alternate as the object seen in front. Anecdotally, increasing the saliency of the pen using motion (e.g. wiggling the pen) or color (e.g. a red pen with a neutral-colored strip) tends to increase the perceptual dominance of the pen.
Published January 3, 2017
Lab alumna Hannah presented some of our work on eye blinks and perceiving motion trajectories (with Matteo Lisi from Paris) at the Applied Vision Association xmas meeting in London. Here’s the abstract:
Perceiving Motion Trajectories during Eye Blinks
Hannah Letitia Goh, Matteo Lisi & Gerrit Maus
During an eye blink, visual input is disrupted while objects in motion continue to change in position. How does this temporal occlusion affect our ability to accurately perceive motion and time? We carried out two experiments to investigate perception of motion trajectories at the time of a blink. In Experiment 1, we presented participants with a moving stimulus on a circular trajectory around fixation that disappeared upon detection of a blink, and instructed them to indicate the perceived location of the stimulus at the point of disappearance with a mouse click. In Experiment 2, participants were presented with a similar moving stimulus that jumped either backward or forward by a variable amount during a blink. Participants were instructed to indicate the perceived direction of the jump. In control conditions the stimulus would disappear (Experiment 1) or jump (Experiment 2) while participants’ eyes remained open. In Experiment 1, we observed significantly greater overshoot of motion on blink trials, with the last perceived stimulus position shifted forward by a constant distance into the period of occlusion during the blink. In Experiment 2, participants perceived a backward jump that occurred during a blink as continuous, consistent with the notion that time during a blink was perceived as ~60-100 ms shorter than in actuality. These results suggest eye blinks are partially filled in with extrapolated trajectory information, and that elapsed time during a blink is perceptually compressed (Duyck et al., 2015, J Vision 15, 370; Irwin & Robinson, 2016, J Exp Psy Hum Perc Perf 42, 1490-6).
