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Aging, Spatial Disparity, and the Sound-Induced Flash Illusion.

DeLoss DJ, Andersen GJ - PLoS ONE (2015)

Bottom Line: However, neither younger nor older individuals showed any significant effect of spatial disparity on the sound-induced flash illusion.Reaction time data was also analyzed.As expected, older individuals showed significantly longer reaction times when compared to younger individuals.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of California Riverside, Riverside, California, United States of America.

ABSTRACT
The present study examined age-related differences in multisensory integration and the effect of spatial disparity on the sound-induced flash illusion--an illusion used in previous research to assess age-related differences in multisensory integration. Prior to participation in the study, both younger and older participants demonstrated their ability to detect 1-2 visual flashes and 1-2 auditory beep presented unimodally. After passing the pre-test, participants were then presented 1-2 flashes paired with 0-2 beeps that originated from one of five speakers positioned equidistantly 100 cm from the participant. One speaker was positioned directly below the screen, two speakers were positioned 50 cm to the left and right from the center of the screen, and two more speakers positioned to the left and right 100 cm from the center of the screen. Participants were told to report the number of flashes presented and to ignore the beeps. Both age groups showed a significant effect of the beeps on the perceived number of flashes. However, neither younger nor older individuals showed any significant effect of spatial disparity on the sound-induced flash illusion. The presence of a congruent number of beeps increased accuracy for both older and younger individuals. Reaction time data was also analyzed. As expected, older individuals showed significantly longer reaction times when compared to younger individuals. In addition, both older and younger individuals showed a significant increase in reaction time for fusion trials, where two flashes and one beep are perceived as a single flash, as compared to congruent single flash trials. This increase in reaction time was not found for fission trials, where one flash and two beeps were perceived as two flashes. This suggests that processing may differ for the two forms for fission as compared to fusion illusions.

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Related in: MedlinePlus

Reaction times depend on the presence of the illusion.Mean reaction times as indicated by age, number of flashes presented, and number of beeps presented. Error bars indicate ±1 standard error of the mean.
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pone.0143773.g005: Reaction times depend on the presence of the illusion.Mean reaction times as indicated by age, number of flashes presented, and number of beeps presented. Error bars indicate ±1 standard error of the mean.

Mentions: Reaction time data was analyzed using an Age (2: Younger, Older) x Flashes (2: 1 flash, 2 flashes) x Beeps (2: 1 beep, 2 beeps) x Speaker Displacement (3: 0m, 0.5m, 1m) mixed analysis of variance. For any effects that violated sphericity we used Greenhouse-Geisser corrections. Original degrees of freedom are reported. There was a significant main effect of beeps on reaction time (F(1,22) = 4.864, p = 0.038, see Fig 5). Reaction times for trials with two beeps were greater than those for one beep trials. However, this may have been partially determined by the interaction of flashes and beeps (F(1,22) = 5.012, p = 0.036). As depicted in Fig 5, the greater reaction for two beep conditions occurred primarily for the single flash as compared to the two flash condition. Interestingly, fusion illusion trials showed reaction times nearly 100ms longer than non-illusion congruent trials for both age groups as indicated by a simple effects analysis (F(1,22) = 5.613, p = 0.027). However, fission illusion trials showed no significant change in RT compared to congruent trials (F(1,22) = 3.253, p = 0.085), with nearly no RT difference in younger individuals, and a small but non-significant difference in older individuals (see Fig 5). Lastly, a significant effect of age was found (F(1,22) = 7.421, p = 0.012). Responses for older individuals were found to be significantly slower than the response times for younger individuals.


Aging, Spatial Disparity, and the Sound-Induced Flash Illusion.

DeLoss DJ, Andersen GJ - PLoS ONE (2015)

Reaction times depend on the presence of the illusion.Mean reaction times as indicated by age, number of flashes presented, and number of beeps presented. Error bars indicate ±1 standard error of the mean.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4664268&req=5

pone.0143773.g005: Reaction times depend on the presence of the illusion.Mean reaction times as indicated by age, number of flashes presented, and number of beeps presented. Error bars indicate ±1 standard error of the mean.
Mentions: Reaction time data was analyzed using an Age (2: Younger, Older) x Flashes (2: 1 flash, 2 flashes) x Beeps (2: 1 beep, 2 beeps) x Speaker Displacement (3: 0m, 0.5m, 1m) mixed analysis of variance. For any effects that violated sphericity we used Greenhouse-Geisser corrections. Original degrees of freedom are reported. There was a significant main effect of beeps on reaction time (F(1,22) = 4.864, p = 0.038, see Fig 5). Reaction times for trials with two beeps were greater than those for one beep trials. However, this may have been partially determined by the interaction of flashes and beeps (F(1,22) = 5.012, p = 0.036). As depicted in Fig 5, the greater reaction for two beep conditions occurred primarily for the single flash as compared to the two flash condition. Interestingly, fusion illusion trials showed reaction times nearly 100ms longer than non-illusion congruent trials for both age groups as indicated by a simple effects analysis (F(1,22) = 5.613, p = 0.027). However, fission illusion trials showed no significant change in RT compared to congruent trials (F(1,22) = 3.253, p = 0.085), with nearly no RT difference in younger individuals, and a small but non-significant difference in older individuals (see Fig 5). Lastly, a significant effect of age was found (F(1,22) = 7.421, p = 0.012). Responses for older individuals were found to be significantly slower than the response times for younger individuals.

Bottom Line: However, neither younger nor older individuals showed any significant effect of spatial disparity on the sound-induced flash illusion.Reaction time data was also analyzed.As expected, older individuals showed significantly longer reaction times when compared to younger individuals.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, University of California Riverside, Riverside, California, United States of America.

ABSTRACT
The present study examined age-related differences in multisensory integration and the effect of spatial disparity on the sound-induced flash illusion--an illusion used in previous research to assess age-related differences in multisensory integration. Prior to participation in the study, both younger and older participants demonstrated their ability to detect 1-2 visual flashes and 1-2 auditory beep presented unimodally. After passing the pre-test, participants were then presented 1-2 flashes paired with 0-2 beeps that originated from one of five speakers positioned equidistantly 100 cm from the participant. One speaker was positioned directly below the screen, two speakers were positioned 50 cm to the left and right from the center of the screen, and two more speakers positioned to the left and right 100 cm from the center of the screen. Participants were told to report the number of flashes presented and to ignore the beeps. Both age groups showed a significant effect of the beeps on the perceived number of flashes. However, neither younger nor older individuals showed any significant effect of spatial disparity on the sound-induced flash illusion. The presence of a congruent number of beeps increased accuracy for both older and younger individuals. Reaction time data was also analyzed. As expected, older individuals showed significantly longer reaction times when compared to younger individuals. In addition, both older and younger individuals showed a significant increase in reaction time for fusion trials, where two flashes and one beep are perceived as a single flash, as compared to congruent single flash trials. This increase in reaction time was not found for fission trials, where one flash and two beeps were perceived as two flashes. This suggests that processing may differ for the two forms for fission as compared to fusion illusions.

Show MeSH
Related in: MedlinePlus