Aging cognition involves declines in basic cognitive functions such as information activation, representation, maintenance, focus, and processing. A paradigm shift is needed to understand cognitive aging across neural, information-processing, and behavioral levels. The authors review empirical data and computational theories that integrate these levels. Deficient neuromodulation is linked to noisy information processing, leading to less distinctive cortical representations, which may underlie cognitive aging deficits. While average life expectancy has increased, cognitive functions decline with age, necessitating an integrated understanding of aging mechanisms. Cognitive aging is studied at behavioral, information-processing, and neurobiological levels. Behavioral studies show declines in fluid intelligence and increased variability. Information-processing studies propose working memory, attention, and processing speed as key factors. Neurobiological studies examine brain aging at anatomical, metabolic, and neurochemical levels. Integration across these levels is challenging, but recent advances in neuroimaging and computational neuroscience offer new insights. Aging affects three facets of information processing: working memory, attention, and processing speed. Neuromodulation, particularly dopamine, declines with age, affecting cognitive functions. Dopamine receptor loss in the prefrontal cortex and striatum is associated with cognitive deficits. Computational theories link deficient neuromodulation to increased neural noise and less distinctive cortical representations, which may explain cognitive aging. Recent computational theories suggest that reduced dopaminergic modulation leads to decreased signal-to-noise ratio, affecting neural information processing. This results in less distinct cortical representations, impacting working memory and attention. Simulations show that reduced responsivity and increased noise in neural processing lead to less distinct internal representations, making cognitive functions more impaired. Theoretical models suggest that deficient neuromodulation may be linked to cognitive aging deficits. Computational simulations support this, showing that reduced dopaminergic modulation leads to increased neural noise and less distinct cortical representations. These findings highlight the importance of neuromodulation in cognitive aging and suggest that further research is needed to understand the mechanisms involved. The authors propose a paradigm shift towards cross-level integration of cognitive aging phenomena. This approach could lead to a better understanding of cognitive aging and inform interventions. Future research should explore the role of neuromodulation in cognitive development and disorders, as well as the effects of dopamine on cognitive functions. The integration of different levels of analysis is essential for a comprehensive understanding of cognitive aging.Aging cognition involves declines in basic cognitive functions such as information activation, representation, maintenance, focus, and processing. A paradigm shift is needed to understand cognitive aging across neural, information-processing, and behavioral levels. The authors review empirical data and computational theories that integrate these levels. Deficient neuromodulation is linked to noisy information processing, leading to less distinctive cortical representations, which may underlie cognitive aging deficits. While average life expectancy has increased, cognitive functions decline with age, necessitating an integrated understanding of aging mechanisms. Cognitive aging is studied at behavioral, information-processing, and neurobiological levels. Behavioral studies show declines in fluid intelligence and increased variability. Information-processing studies propose working memory, attention, and processing speed as key factors. Neurobiological studies examine brain aging at anatomical, metabolic, and neurochemical levels. Integration across these levels is challenging, but recent advances in neuroimaging and computational neuroscience offer new insights. Aging affects three facets of information processing: working memory, attention, and processing speed. Neuromodulation, particularly dopamine, declines with age, affecting cognitive functions. Dopamine receptor loss in the prefrontal cortex and striatum is associated with cognitive deficits. Computational theories link deficient neuromodulation to increased neural noise and less distinctive cortical representations, which may explain cognitive aging. Recent computational theories suggest that reduced dopaminergic modulation leads to decreased signal-to-noise ratio, affecting neural information processing. This results in less distinct cortical representations, impacting working memory and attention. Simulations show that reduced responsivity and increased noise in neural processing lead to less distinct internal representations, making cognitive functions more impaired. Theoretical models suggest that deficient neuromodulation may be linked to cognitive aging deficits. Computational simulations support this, showing that reduced dopaminergic modulation leads to increased neural noise and less distinct cortical representations. These findings highlight the importance of neuromodulation in cognitive aging and suggest that further research is needed to understand the mechanisms involved. The authors propose a paradigm shift towards cross-level integration of cognitive aging phenomena. This approach could lead to a better understanding of cognitive aging and inform interventions. Future research should explore the role of neuromodulation in cognitive development and disorders, as well as the effects of dopamine on cognitive functions. The integration of different levels of analysis is essential for a comprehensive understanding of cognitive aging.