Hemispheric Lateralisation

Question 1

Define Hemispheric Lateralisation

Answer 1

The two hemispheres of the brain are functionally different
Certain processes are mainly controlled by one hemisphere rather than the other

Question 2

Which hemisphere controls language

Answer 2

Left (Broca’s and Wernicke’s areas)

Question 3

Sensorimotor Processing (wiring)

Answer 3

Contralateral wiring
Motor and sensory areas are controlled by both hemispheres
The motor area is cross-wired (contralateral wiring)

Question 4

Visual Processing (wiring)

Answer 4

Contralateral and Ipsilateral wiring
Visual area has contralateral and ipsilateral wiring (opposite and same-sided)
Similar arrangement for auditory area

Question 5

Evaluation (STRENGTH) - Lateralisation in the connected brain

Answer 5

Research showing two hemispheres process information differently

Gereon Fink et al (1996) - used PET scans to identify which brain areas were active during visual task. Ppts had connected brains. Right hemisphere was more active. When required to focus on finer details, Left hemisphere dominated

Suggests that hemispheric lateralisation is a feature of both connected and split-brain

Question 6

Evaluation (LIMITATION) - One brain

Answer 6

Idea that the left hemisphere is the analyser and right hemisphere is the synthesiser may be wrong
Research suggests people do not have a dominant side of their brain

Jared Nielson et al (2013) - analysed brain scans from over 1000 people age 7-29. Found that people used certain hemispheres for certain tasks. However no evidence of a dominant side

Suggests the notion of right or left brained people is wrong and both hemispheres work together

Question 7

Evaluation - Lateralisation VS Plasticity

Answer 7

Lateralisation is adaptive as it enables two tasks to be performed simultaneously with greater efficiency

Lesley Rogers et al (2004) - showed that lateralised chickens could find food while watching for predators but ‘normal’ chickens couldn’t

Neural Plasticity could also be seen as adaptive. Following damage through illness or trauma, some functions can be taken over by non-specialised areas in the opposite hemisphere

Holland et al (1996) - language function can switch sides