Flash-lag effect: complicating motion extrapolation of the moving reference-stimulus paradoxically augments the effect

Abstract

One fundamental property of the perceptual and cognitive systems is their capacity for prediction in the dynamic environment; the flash-lag effect has been considered as a particularly suggestive example of this capacity (Nijhawan in nature 370:256-257, 1994, Behav brain sci 31:179-239, 2008). Thus, because of involvement of the mechanisms of extrapolation and visual prediction, the moving object is perceived ahead of the simultaneously flashed static object objectively aligned with the moving one. In the present study we introduce a new method and report experimental results inconsistent with at least some versions of the prediction/extrapolation theory. We show that a stimulus moving in the opposite direction to the reference stimulus by approaching it before the flash does not diminish the flash-lag effect, but rather augments it. In addition, alternative theories (in)capable of explaining this paradoxical result are discussed.

Neurobiological Mechanisms Behind the Spatiotemporal Illusions of Awareness Used for Advocating Prediction or Postdiction

“…This creates the illusion of a spatial lag. This explanation is valid also for the flash-initiated conditions, the conditions where the post-flash movement directions are unpredictable and the conditions where the pre-flash stimulation includes contradictory motion direction signals that could nullify or complicate prediction (Khurana and Nijhawan, 1995; Whitney and Murakami, 1998; Bachmann et al, 2012). In some sense the retouch theory explanation can be considered as a variety of the latency difference account.…”

“…Compared to the perceived position of the static flash this spatial advancement provides the foundation for the illusory flash-lag. However, this account cannot explain FLE found in the following experimental conditions: (i) the flash-initiated conditions where the moving stimulus begins to move only after the flash (i.e., no prediction basis is present; Khurana and Nijhawan, 1995), (ii) motion-reversing (Whitney and Murakami, 1998) conditions where the moving stimulus changes its motion direction, (iii) conditions where in addition to the moving reference stimulus another stimulus approaches the reference from an opposite direction and thereby provides a conflicting, canceling motion vector before the flash (Bachmann et al, 2012), (iv) conditions where the flash itself is also briefly in motion (Bachmann et al, 2003). Thus, the events after the flash must be responsible for the FLE.…”

“…The retouch theory explanation (Bachmann et al, 2003, 2012; Bachmann, 2010) is this: because the action of NSP takes more time than SP-encoding and because no awareness of the SP-represented contents emerges before NSP-modulation has had its effect, the percept in awareness emphasizes features that are or become present in SP somewhat later. For the features of the static flash this means that its initial position as stored in sensory memory will be “retouched” for consciousness, but for the features of the moving stimulus this means “retouching” an advanced spatial position for consciousness.…”

Postdiction: its implications on visual awareness, hindsight, and sense of agency

“…However, the mere fact of different neural delay may be somewhat dubious (see Moutoussis and Zeki, 1997; Nishida and Johnston, 2002). Moreover, the situation seems to be a bit more complicated, and other factors such as whether stimulation comes in stream or flashed plays a role (Bachmann, 2010, 2013; Bachmann et al, 2012). …”

A comparison of visual and auditory representational momentum in spatial tasks

“…A number of studies have dealt with several effects that are specific either to motion onset (the Fröhlich effect: Getzmann, 2005b;Kerzel & Gegenfurtner, 2004;Müsseler & Aschersleben, 1998), to a time point within the trajectory (the flash-lag effect: Alais & Burr, 2003;Bachmann, Murd, & Põder, 2012;Linares, López-Moliner, & Johnston, 2007;Nijhawan, 2001;Vreven & Verghese, 2005), or to the final position of motion (representational momentum: Freyd & Finke, 1984;Getzmann, Lewald, & Guski, 2004;Hubbard, Kumar, & Carp, 2009;Mateeff & Hohnsbein, 1988).…”