Most scientists believe rivalry occurs only when there’s “spatial conflict”—two objects striking the same place on the retina at the same time as our eyes move. But the retina isn’t the only filter or organizer of visual information. There’s also the “non-retinal reference frame”—objects such as mountains or chairs that locate things in space and make the world appear stable even when our eyes are moving.
“We asked: what if visual ambiguities are not presented on the same spot on the retina, but on the objects [in the frame] as they move around,” says California Institute of Technology cognitive scientist Jeroen J.A. van Boxtel. Indeed, he and colleague Christof Koch found evidence of rivalry in this reference frame, with surprising effects on the better-understood spatial conflict. The findings, which will appear in an upcoming issue of Psychological Science, a journal published by the Association of Psychological Science, offer intriguing clues to how the visual system works.
In their experiments, van Boxtel and Koch created spatial conflict with a “motion quartet,” which changes the arrangement of four dots. If the dots are displaced in certain ways, the visual system isn’t sure if the movement is vertical or horizontal. If the dots move to an altogether different space, there’s no rivalry. Then the researchers upped the perceptual ante by creating an object reference frame with three white discs and shifting it, too, along with or in opposition to the smaller dots.
Seven male and female participants viewed the changing arrangements in four conditions. In one, both dots and discs remained stationary (creating spatial rivalry); in each of two, either dots or discs moved right or left; in the fourth, both moved horizontally together (creating ambiguity in the frame). Each time, participants had to press a button indicating whether the dots moved horizontally or vertically. The presses were analyzed for perceived movement “bias” (more horizontal or vertical) and duration—evidence either of rivalry or visual clarity.
The results: Even when the dots moved to another space altogether—so there was no spatial conflict—the moving discs created the effect of perceptual ambiguity. But the researchers also found that visual rivalry disappeared when the dots were stationary and the disks moved (that is, the dots were not linked to the disks). It was as if the brain had bigger fish—object-frame rivalry—to fry.
In subsequent experiments—one changing the vertical relationship of the dots and one placing the dots outside the white discs—the researchers got results similar to those they would have gotten without the frame. Their conclusion: The visual system is working out object-frame rivalry as it would spatial rivalry, probably with the same brain regions and processes.
For more information about this study, please contact: Jeroen J. A. van Boxtel at firstname.lastname@example.org.
The APS journal Psychological Science is the highest ranked empirical journal in psychology. For a copy of the article "Visual rivalry without spatial conflict" and access to other Psychological Science research findings, please contact Divya Menon at 202-293-9300 or email@example.com.
Divya Menon | EurekAlert!
3D images of cancer cells in the body: Medical physicists from Halle present new method
16.05.2018 | Martin-Luther-Universität Halle-Wittenberg
Better equipped in the fight against lung cancer
16.05.2018 | Friedrich-Alexander-Universität Erlangen-Nürnberg
So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics
Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...
The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...
A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.
The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...
Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.
Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...
A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.
Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...
02.05.2018 | Event News
13.04.2018 | Event News
12.04.2018 | Event News
18.05.2018 | Power and Electrical Engineering
18.05.2018 | Information Technology
18.05.2018 | Information Technology