Performing a task jointly enhances the sound-induced flash illusion

Abstract

Our different senses are stimulated continuously. Through multisensory integration, different sensory inputs may or may not be combined into a unitary percept. Simultaneous with this stimulation, people are frequently engaged in social interactions, but how multisensory integration and social processing combine is largely unknown. The present study investigated if, and how, the multisensory sound-induced flash illusion is affected by a social manipulation. In the sound-induced flash illusion, a participant typically receives one visual flash and two auditory beeps and she/he is required to indicate the number of flashes that were perceived. Often, the auditory beeps alter the perception of the flashes such that a participant tends to perceive two flashes instead of one flash. We tested whether performing a flash counting task with a partner (confederate), who was required to indicate the number of presented beeps, would modulate this illusion. We found that the sound-induced flash illusion was perceived significantly more often when the flash counting task was performed with the confederate compared to performing it alone. Yet, we no longer find this effect if visual access between the two individuals is prevented. These findings, combined with previous results, suggest that performing a multisensory task jointly - in this case an audiovisual task - lowers the extent to which an individual attends to visual information - which in turn affects the multisensory integration process.

What you see is what you hear: Twenty years of research using the Sound-Induced Flash Illusion

“…As shown in Figure 4 the SOA between the first and the second tone systematically alters the strength of the illusion, therefore selection of these parameters has important consequences for performance. It has recently been shown that performing the SIFI task with a confederate present can enhance the illusion (Wahn et al, 2020). This study asked the confederate to judge the number of beeps, whilst the participant judged the number of flashes.…”

Neural foundations of cooperative social interactions

“…It was shown that groups achieve collective benefits in joint visuomotor tasks that require coordination between eyes and hands (Ganesh et al, 2014;Knoblich and Jordan, 2003;Newman-Norlund et al, 2008;Reed et al, 2006;Takagi et al, 2017). Other research (Brennan and Enns, 2015b;Neider et al, 2010;Wahn et al, 2017a;Wahn and König, 2016) has shown that there are benefits to working together on tasks that involve finding or following objects in different places. Also, Rajaram and Pereira-Pasarin (2010) and Bietti and Sutton (2015) showed that there are benefits for the group when people work together to remember things.…”