A drift diffusion model analysis of age-related impact on multisensory decision-making processes

Area of Science:

• Cognitive Neuroscience
• Human Aging Research
• Sensory Integration

Background:

• Older adults (OAs) often exhibit slower and less accurate perceptual decision-making compared to younger adults.
• Despite these deficits, OAs demonstrate significant benefits from integrating information across multiple senses (multisensory integration).
• The underlying cognitive mechanisms driving these contrasting age-related effects in perception and multisensory processing remain poorly understood.

Purpose of the Study:

• To investigate age-related differences in perceptual decision-making across visual, auditory, and audiovisual conditions.
• To explore how multisensory integration influences decision-making speed and accuracy in older adults.
• To elucidate the latent cognitive processes involved in age-related multisensory decision formation using computational modeling.

Main Methods:

• Conducted an online object categorization task with 212 participants aged 18-90 years.
• Assessed reaction times (RTs) and choice accuracy across unimodal (visual, auditory) and bimodal (audiovisual) sensory conditions.
• Applied Hierarchical Drift Diffusion Modelling (HDDM) to analyze age-related effects on evidence accumulation and response caution.

Main Results:

• Older adults were generally slower and less accurate across all sensory conditions.
• Older adults showed larger reaction time reductions in audiovisual versus visual conditions, indicating enhanced multisensory benefits for decision speed.
• HDDM revealed slower evidence accumulation in older adults, with increased response caution on difficult audiovisual trials.
• Crucially, multisensory benefits in evidence accumulation increased with age for easier trials, but not for harder trials where caution dominated.

Conclusions:

• Age-related declines in perceptual speed are partially offset by enhanced multisensory integration benefits, particularly in decision speed.
• Multisensory integration aids decision-making in older adults by increasing the efficiency of evidence accumulation, especially for less demanding tasks.
• These findings reconcile apparent discrepancies in aging research by highlighting age-related improvements in the cognitive mechanisms underlying multisensory decision formation.