Understand the lateralisation of function in the hemispheres, including:…

The idea

Lateralisation means the brain is asymmetrical, with specific processes dominant in one hemisphere. The left hemisphere controls the right side of the body and dominates language and logic. The right hemisphere controls the left side and excels in spatial awareness and creativity. The corpus callosum connects the hemispheres, enabling communication. Lateralisation is used to explain sex differences, suggesting males have greater right-hemisphere dominance for spatial skills and females greater left-hemisphere dominance for language. A strength is support from brain imaging. A weakness is that it oversimplifies complex behaviours and ignores neuroplasticity and environmental factors in shaping cognitive differences between males and females.

What earns the marks

• Define lateralisation as the asymmetrical distribution of functions between the left and right hemispheres.
• Identify the left hemisphere's role in language processing and controlling the right side of the body.
• Identify the right hemisphere's role in spatial awareness and controlling the left side of the body.
• Describe the corpus callosum as the structure that facilitates communication between the two hemispheres.
• Evaluate lateralisation as an explanation for sex differences by citing biological evidence as a strength and reductionism as a weakness.

Common mistakes and how to put them right

• Confusing which hemisphere controls which side of the body.

  Put it right: Control is contralateral, meaning the left hemisphere controls the right side and vice versa.

• Assuming one hemisphere is solely responsible for a complex task.

  Put it right by understanding that while one may be dominant, both hemispheres communicate via the corpus callosum to complete tasks.

• Stating that lateralisation perfectly explains all sex differences.

  Put it right by acknowledging that environmental factors and neuroplasticity also play significant roles.

Exam tips

• When evaluating lateralisation as an explanation for sex differences, always provide both a strength (e.g., scientific imaging) and a weakness (e.g., ignores socialisation).
• Use the term 'contralateral control' to describe how each hemisphere controls the opposite side of the body to demonstrate precise psychological vocabulary.
• Remember that the corpus callosum is a bridge; if it is severed, the hemispheres cannot share information, which is key in split-brain research.