The relationship between flash based illusory line motion and exogenous visual attention.

Abstract

If a bar suddenly appears between 2 squares after 1 of the squares flashes the bar appears to shoot away from the flashed square toward the other. This occurs despite the bar actually having been presented all at once. This illusory motion is sufficiently strong to cancel real motion drawn in the opposite direction. One explanation for the illusion in these displays is based upon the prior entry benefits generated by exogenous attention at the flashed location. These prior entry benefits can be offset by real motion in the opposite direction, which enables 1 to quantify the illusion based upon the area between the response curves following left and right flashes. The influence of attention can be quantified as the costs plus benefits during an exogenous cuing study involving target discrimination. The current study required participants to complete motion direction discrimination trials and a set of target discrimination trials following noninformative peripheral cues. If attention is involved in the motion illusion during these displays then those who show large effects of attention during cuing should also show large illusions. Correlation analyses confirmed a positive relationship existed between the costs plus benefits of exogenous attention and the illusory motion. (PsycINFO Database Record

Comparisons of flashILM, transformational apparent motion, and polarized gamma motion indicate these are three independent and separable illusions

“…In addition to ILM area , the cancelation procedure also allows the examination of decision times as a function of distance from the point of subjective equality. Previous studies have shown that decision times are described by a distance decay function (Ha et al, 2018;Hamm, 2017;Han & Hamm, 2018;Han et al, 2016). The tendency for decisions to slow as the condition approaches the point of subjective equality indicates that the illusory and real motion are cancelling and are not consistent with the point of subjective equality reflecting the case in which either the real or the illusory motion is being perceived with equal probability (Hamm, 2017;Han & Hamm, 2018;Han et al, 2016).…”

“…This general approach will be referred to as the cancelation procedure. Where Steinman et al (1995) utilized PGM-type displays, cancelation of ILM through the use of real motion has been successfully implemented with both flash ILM (Ha, Li, Patten, & Hamm, 2018;Hamm, 2017;Han & Hamm, 2018;Han, Zhu, Corballis, & Hamm, 2016) and TAM (Hamm, 2017). With the direction of ILM being determined by the side of the single stimulus (PGM), the flash ( flash ILM), or the box with the matching attribute (TAM), the cancelation procedure results in a series of measurements over real-motion conditions for left-and right-side inducers.…”

“…In the present investigation we employed the standardized protocols for display conditions, illusion quantification, and data analysis recommended by Han et al (2016), which have been successfully employed and adhered to in a number of subsequent studies (Ha et al, 2018;Hamm, 2017;Han & Hamm, 2018). In other words, if two protocols are simply interchangeable methods for producing a common illusion, a participant's ILM area from one protocol should predict their ILM area from the other.…”

“…Adopting an individual-differences approach has established that the link between exogenously cued attention and flash ILM in that the magnitude of a participant's costs plus benefits during a cued discrimination task predicts the magnitude of the illusion, as indexed by ILM area (Ha et al, 2018). This link has been further supported by the finding that the brain regions associated with exogenous attention and motion are active while participants view flash ILM displays (Hamm et al, 2014), as well as by the finding that a patient population with known deficits in attention have a reduced flash ILM area , relative to healthy controls (Crawford et al, 2010).…”

“…We used the cancelation paradigm to quantify the illusion as the area between the percept functions for left-and rightsided inducers (Ha et al, 2018;Hamm, 2017;Han & Hamm, 2018;Han et al, 2016), for standard flash ILM, TAM, and PGM displays. Since flash ILM has sometimes involved presenting two boxes with the bar visible, with the illusion being a perception, when the bar changes color, of the color spreading over the bar away from the flash (Crawford, Kean, Klein, & Hamm, 2006), this protocol will also be included.…”