Sensory functioning and intelligence in old age: A strong connection.

TLDR

Visual and sensory acuity may reflect the physiological integrity of the aging brain, a common cause hypothesis. The study examined age, visual and auditory acuity, and intelligence in 156 older adults (age 70–103) using 14 tests covering speed, reasoning, memory, knowledge, and fluency. Visual and auditory acuity explained 49.2 % of overall and 93.1 % of age‑related variance in intelligence, fully mediating age differences in cognitive abilities and strongly predicting late‑life intellectual functioning.

Abstract

Relations among age, sensory functioning (i.e., visual and auditory acuity), and intelligence were examined in a heterogeneous, age-stratified sample of old and very old individuals (N = 156, M age = 84.9 years, age range = 70-103). Intelligence was assessed with 14 tests measuring 5 cognitive abilities (speed, reasoning, memory, knowledge, and fluency). Together, visual and auditory acuity accounted for 49.2% of the total and 93.1% of the age-related reliable variance in intelligence. The data were consistent with structural models in which age differences in intelligence, including speed, are completely mediated by differences in vision and hearing. Results suggest that sensory functioning is a strong late-life predictor of individual differences in intellectual functioning. Explanations are discussed, including the possibility that visual and sensory acuity are indicators of the physiological integrity of the aging brain (common cause hypothesis).