Merging brains symbolizing cognitive aging and individual differences.

Unlocking the Aging Brain: How Sex and Handedness Impact Language Skills

Nico Varela in Health & Wellness December 2025 • 5 min read.

"New research reveals surprising insights into how age, sex, and handedness influence language lateralization in the brain, challenging conventional models."

For years, scientists have strived to understand how our brains handle language, one of the most complex functions we possess. Think about how effortlessly you string words together, understand conversations, or read articles like this one. But what happens to this ability as we age? Does everyone experience these changes in the same way? Recent research is shedding light on these questions, revealing that sex and handedness play significant roles in how our language skills evolve over time.

Historically, studies have often overlooked the nuances of individual differences, particularly the roles of sex and handedness. Early research often treated these factors as mere variables, failing to appreciate how they might uniquely shape language processing in the brain. This new study addresses these gaps by examining a large group of participants with a relatively even distribution of ages and handedness, aiming to provide a more complete picture of language lateralization – the tendency for certain brain functions to be localized to one side of the brain.

At the heart of this exploration is the 'HAROLD' model (Hemispheric Asymmetry Reduction in Older Adults), which suggests that as we age, our brains become less specialized, using both hemispheres more equally to compensate for declining function. However, the latest findings challenge this model, suggesting that the relationship between aging and language lateralization is more complex and varies significantly between individuals.

The Surprising Differences in Language Lateralization Between Men and Women

Merging brains symbolizing cognitive aging and individual differences.

The study, led by Rodolphe Nenert and colleagues, used functional magnetic resonance imaging (fMRI) to observe brain activity during semantic decision and verb generation tasks. Participants included 99 healthy men (33 left-handed) and 125 healthy women (44 left-handed), with ages ranging from 18 to 76. This diverse group allowed researchers to explore how age, sex, and handedness interact to influence language processing.

One of the key findings was that language lateralization decreases with age only in right-handed men and specifically in the temporo-parietal cortical area. This means that as right-handed men age, they tend to use both sides of their brains more equally when processing language. In contrast, this pattern was not observed in women or left-handed individuals, suggesting that the aging process affects language skills differently based on sex and handedness.

Men vs. Women: The study found that the proportion of atypical language lateralization was similar between men and women, challenging previous assumptions about sex-based differences in brain function.
Right-Handed vs. Left-Handed: Atypical language lateralization was more common in left-handed participants, which aligns with previous research. This suggests that handedness is a significant factor in how the brain organizes language processing.
Age-Related Changes: The decrease in language lateralization with age was only observed in right-handed men, indicating that the aging brain adapts differently based on sex and handedness.

These results challenge the traditional HAROLD model, which posits a general reduction in hemispheric asymmetry with age. Instead, the study suggests a more nuanced relationship where the influence of age on language lateralization is contingent on sex and handedness. The researchers propose that the brain's functional organization and compensatory mechanisms may differ significantly between these groups.

What This Means for You

While this research is primarily for the scientific community, its findings offer valuable insights for everyone. Understanding how our brains change as we age—and how these changes differ between men and women, right-handers and left-handers—can help us develop more effective strategies for maintaining cognitive function. It also underscores the importance of considering individual differences in future research and clinical practice. By recognizing these nuances, we can create more tailored approaches to support brain health and language skills throughout life.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1016/j.brainres.2017.08.021, Alternate LINK

Title: Age-Related Language Lateralization Assessed By Fmri: The Effects Of Sex And Handedness

Subject: Developmental Biology

Journal: Brain Research

Publisher: Elsevier BV

Authors: Rodolphe Nenert, Jane B. Allendorfer, Amber M. Martin, Christi Banks, Jennifer Vannest, Scott K. Holland, Jerzy P. Szaflarski

Published: 2017-11-01

Everything You Need To Know

What is language lateralization and why is it important?

Language lateralization refers to the brain's tendency to process language predominantly in one hemisphere. This is significant because understanding how language lateralizes helps us understand how our brains organize complex functions. The degree to which language is lateralized can vary, and atypical lateralization (where language is processed more evenly across both hemispheres or predominantly in the right hemisphere) can impact language skills.

What is the 'HAROLD' model, and why is it significant?

The 'HAROLD' model (Hemispheric Asymmetry Reduction in Older Adults) suggests that as people age, their brains rely less on one specific hemisphere for certain functions, using both hemispheres more equally to compensate for any decline. This model is important because it attempts to explain how the brain adapts to aging. However, recent research suggests that the HAROLD model may be too simplistic and that the changes that occur depend on factors such as sex and handedness.

What is fMRI and how was it used in the study?

The fMRI (functional magnetic resonance imaging) is a neuroimaging technique used to measure brain activity by detecting changes associated with blood flow. This is significant because it allows researchers to observe which parts of the brain are active during specific tasks, such as language processing. In this instance, it was used to observe the language processing of different sexes with different hand dominance and how aging changes the brain usage.

How does aging affect language lateralization differently in men and women?

The study highlights that language lateralization decreases with age only in right-handed men, specifically in the temporo-parietal cortical area. This implies that as right-handed men age, they use both sides of their brains more equally when processing language. This is significant because it challenges the idea that aging affects everyone's brain in the same way, suggesting that sex and handedness play a crucial role in how the brain adapts over time. The study found that women and left-handed men did not demonstrate the same trend.

Why is handedness an important factor to consider in brain function and language processing?

Handedness, whether someone is right-handed or left-handed, appears to play a significant role in how the brain processes language. Atypical language lateralization is more common in left-handed individuals. This finding is important because it suggests that the brain's organization for language may differ depending on handedness, and it underscores the need to consider individual differences when studying brain function. The interaction of how the sex differences and the hand dominance differences is still not completely understood, and more studies are needed.