Predicting combinations of left and right asymmetries

Area of Science:

• Neuroscience
• Human Genetics
• Behavioral Science

Background:

• Human laterality, including handedness and eye dominance, exhibits complex patterns of association.
• Previous models often categorized individuals into distinct 'types' of preference.
• The RS+ gene theory offers a framework for understanding genetic influences on lateralization.

Purpose of the Study:

• To predict and analyze combinations of asymmetries for various laterality variables.
• To investigate the influence of the RS+ gene on the combination of laterality traits.
• To examine the association between handedness, eye dominance, and anatomical asymmetries.

Main Methods:

• Statistical analysis of paired laterality variables (e.g., writing hand, throwing hand, eye dominance, foot preference).
• Application and testing of the RS+ gene theory to observed patterns of asymmetry.
• Replication of analyses to ensure reliability of findings, particularly for hand preferences.

Main Results:

• Many laterality variable pairs combine as expected by chance, influenced by the RS+ gene.
• Stronger associations were found for writing and throwing handedness, and hand/foot preferences, indicating additional factors.
• Patterns of preference (e.g., RRR, RRL) showed orderly relationships with hand differences in peg moving time.

Conclusions:

• The RS+ gene theory successfully explains many observed combinations of laterality asymmetries.
• Individual differences in hand preference are better understood as a continuous distribution of asymmetry rather than discrete types.
• Findings support the role of genetic factors and continuous asymmetry in shaping human lateralization patterns.