Audio-haptic cue integration across the lifespan

Optimal integration of multisensory information has frequently been shown
to benefit perception by speeding up responses and increasing perceptual
precision and accuracy. These effects, however, are often demonstrated in
young adults, and to a lesser extent in older adults or children, with a
scarcity of studies examining how optimal integration changes across the
lifespan. Furthermore, most studies have used different tasks and
approaches to measure multisensory processing adaptation over large age
ranges, making it difficult to compare between them. Here, by using the
same adaptive size discrimination task and a cross-sectional design, we
investigated how audio-haptic cue integration performance changes over
the lifespan in children, younger adults, and older adults (age range
spanning from 7 to 70years). Participants were asked to give size
discrimination judgements for physical objects of different sizes using either
touch or hearing (unimodal) or both at the same time (bimodal).
Discrimination thresholds were assessed for unimodal and bimodal stimulus
presentation and compared with predictions from a maximum likelihood
estimation (MLE) model. Results show that children do not make use of
audio-haptic multisensory size information until around 13 years of age,
while both younger and older adults benefit from integrating multisensory
information, leading to increased precision. These results corroborate and
extend the findings from previous studies that used different approaches,
showing that children only gain from multisensory integration late in
childhood, but that its benefits are preserved until later in life. It further
suggests that integration of non-visual information, which becomes
increasingly important with declining visual function later in life, allows
individuals to effectively make use of redundant information, thereby
offering an advantageous compensatory mechanism for declining sensory
function.