SUMMARY 11b: Hemispheric specialisation, what is being localised

HANDS & HEMISPHERES

• Right-handedness is dominant in 85-90% of people.

• No significant cognitive differences between right and left-handers.

• Ancient traits indicated by cave paintings and tool usage.

SPECIALISATION MODELS

• Each hemisphere specializes in different psychological processes.

• Left Hemisphere (LH):

  • Specialised for language-related processes, planning motor activity, fine temporal processing.

  • Aphasia (language impairment) and apraxia (difficulty in planned motor tasks) relate to LH damage.

• Right Hemisphere (RH):

  • More diffused processing compared to LH, specialized for spectral resolution.

MOTOR ACTIVITY & PROCESSING

• LH handles planned motor activity, gestures, essential for language evolution from gestural to vocal.

• LH excels in temporal (time and location) resolution; RH focuses on spectral (colour and contrast) resolution in stimuli.

COGNITIVE PROCESSING

• LH operates logically and analytically, processing information in a sequential manner.

• RH is more holistic, focusing on overall configurations of stimuli.

• LH: details

• RH: global

INDIVIDUAL DIFFERENCES

• Hemispheric organization may affect individual behavior.

• Preference for cognitive styles:

  • LH: logical and verbal.

  • RH: intuitive (reasoning) and visual.

COGNITIVE SET (mental strategy/habitual approach) & BIAS

• Individual approach to problems (cognitive set) impacts lateralization (hemisphere specialisation).

• Strategies can shift hemisphere dominance, rather than fixed traits.

• people with similar brains may show different lateralisation patterns depending on their strategy. 

• training or shifting strategies can alter which hemisphere takes the lead.