Purchase this article with an account.
Jessica N. Cali, Patrick J. Bennett, Allison B. Sekular; The effect of noise on motion binding is similar in younger and older adults. Journal of Vision 2014;14(10):270. doi: 10.1167/14.10.270.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
The level of internal noise affecting motion processing is higher in older than younger adults (Bennett et al., Vision Res, 2007; Bocheva et al., Exp Brain Res, 2013). Normally, higher noise is associated with poorer performance; however, Lorenceau(Vision Res, 1996) showed that visual stimulus noise sometimes can help perception. In Lorenceau's task, a square stimulus composed of dots (5/side) maintained a fixed orientation while rotating around central fixation. The square's rotation was decomposed into two sinusoidal components corresponding to the motion of the horizontal and vertical lines. Critically, the corners of the square were removed, so participants had to combine the two motion components to discriminate the global rotation (clockwise or counter-clockwise). Lorenceau found that motion binding was easier when noise was added to the individual dots forming the square. Here we asked whether age-related changes in internal noise would affect perception, with seniors potentially requiring less external noise to perceive the global motion. We tested younger (19-27 years; N=6) and older (64-75 years; N=6) adults using Lorenceau's stimulus displayed for 4 durations (150ms, 300ms, 600ms, 1200ms) at 3 levels of external noise (0.0002, 0.027, 0.081). In general, we found a similar pattern of results as Lorenceau, with better performance at higher levels of noise, but the effect of the noise depended on stimulus duration. At 150ms, there was no difference across noise levels for younger or older adults. As trial durations increased, performance increased in the moderate and high noise conditions, and decreased in the low noise condition. A similar overall pattern was observed for both age groups, although maximum performance differed numerically, but not significantly, for older (~85%) versus younger (~95%) observers. Additional studies are examining whether clearer age-related effects are seen at more extreme noise levels, and whether seniors might benefit from even longer stimulus durations.
Meeting abstract presented at VSS 2014
This PDF is available to Subscribers Only