Visual Flicker in the Gamma-Band Range Does Not Draw Attention

Abstract

External transients, such as a flash or a startling sound, are believed to capture attention. Bauer, Cheadle, Parton, Müller, and Usher reported that attention can also be captured by a stimulus that flickers subliminally at 50 Hz, presumably by entrainment of neurons to the flicker frequency. In their reaction time (RT) task, participants had to locate a subtle change in the spatial frequency content of one of three Gabors (the target). Prior to target onset, presumably subliminal 50-Hz flicker in one of the Gabors served as a spatial cue. Bauer et al. found faster RTs when the cued location was congruent with the target location than when the cue was incongruent with the target location. In their experiments, the cue stopped to flicker at 50 Hz at target onset and was replaced by a stimulus flickering at 100 Hz (i.e., the screen refresh rate). In the present study, we show that the transition from 50 to 100 Hz results in a flash-like impression that can be localized above chance. We suggest that the illusory transition flash interfered with the localization of the subtle target, which contributed to the congruency effect. In support of this view, participants selected the flickering object more often than the non-flickering object when they failed to respond to the target. Further, no cueing effects were observed when the cue continued to flicker until the end of the trial or when the target was a salient change in polarity. In our view, the cueing effect occurs because observers confuse the illusory transition flash with the target when the two are similar. When truly subliminal flicker is used (70-Hz flicker), very small cueing effects persist in the absence of an illusory transition flash but may be accounted for by small effects on reaction time unrelated to attention.

Transient twinkle perception is induced by sequential presentation of stimuli that flicker at frequencies above the critical fusion frequency

“…Reports have shown that the perceived luminance of the above-CFF flicker was identical to that of a non-flickering stimulus whose luminance was matched to the averaged luminance of the above-CFF flicker (Cheadle et al, 2011;van Diepen et al, 2010). This is well known as the TalbotPlateau law (Nelson & Bartley, 1964;Stockman & Plummer, 1998).…”

“…For example, steady-state visually evoked potentials have been observed for above-CFF stimuli (Herrmann, 2001;Lyskov, Ponomarev, Sandstrom, Mild, & Medvedev, 1998; RamosJúnior, Celino, Rodor, Ribeiro, & Muller, 2011). In addition, a single flash of a half sinusoid can be detected at up to 600 Hz (Levinson, 1968).Recently, an interesting phenomenon relevant to above-CFF stimuli has been reported: When two different above-CFF stimuli are sequentially presented, a transient flash is perceived (Cheadle, Parton, Muller, & Usher, 2011;van Diepen, Born, Souto, Gauch, & Kerzel, 2010). In these studies, two stimuli were presented sequentially at the same position; one was the Bflicker stimulus,^in which two differentluminance frames were alternatively presented, and the other was the Bcontinuous stimulus,^in which all frames had identical luminances.…”

“…1c-d). This hypothesis is consistent with Cheadle et al (2011), who showed that TTP was attenuated when the flicker amplitude was ramped down, resulting in a smooth transition to the continuous stimuli and a small luminance step.Several studies have dealt with TPP as an artifact of experimental procedures, because the primary purpose of these studies was to examine whether or not stimuli flickering at the gamma band frequency (25-70 Hz) could trigger unconscious selective attention (Bauer, Cheadle, Parton, Muller, & Usher, 2009;Cheadle et al, 2011;van Diepen et al, 2010). Thus, the perceptual mechanism of TTP itself has not yet been directly investigated in these studies.…”

“…Recently, an interesting phenomenon relevant to above-CFF stimuli has been reported: When two different above-CFF stimuli are sequentially presented, a transient flash is perceived (Cheadle, Parton, Muller, & Usher, 2011;van Diepen, Born, Souto, Gauch, & Kerzel, 2010). In these studies, two stimuli were presented sequentially at the same position; one was the Bflicker stimulus,^in which two differentluminance frames were alternatively presented, and the other was the Bcontinuous stimulus,^in which all frames had identical luminances.…”

“…When these stimuli were presented at the same location (Fig. 1a), however, a transient Btwinkle^was occasionally perceived (Cheadle et al, 2011;van Diepen et al, 2010). We call this phenomenon Btransient twinkle perception^(TTP, Fig.…”