BIOPSYCHOLOGY Flashcards
Explain Lashley’s study (1950) using rats
- trained rats to navigate a maze, then surgically removed 10-50% of their cerebral cortex (involved in memory) to see how it affected their memory of the task
- the more brain tissue he removed (regardless of location), the worse the rats performed.
- He found that no single area of the brain was solely responsible for maze learning (opposing localisation theory)
-> memory and learning are distributed across the brain, supporting the holistic theory rather than localisation.
Lashley suggested that if one part of the brain is damaged, other parts can take over its functions (equipotentiality)
❌ findings may be reductionist as they have been generalised to humans, and this simplifies human behaviour
What evidence is there for recruitment of homologous areas (functional recovery)
Name the patients
Patient EB, who had a hemispherectomy (part of brain is removed) at 2.5 years old, showed the right hemisphere was able to develop language abilities after some initial aphasia (loss of ability express or understand language)
Describe Czeisler et als findings (circadian rhythm)
The role of artificial lighting was previously underestimated during the time in which Siffre carried out his research, however research has since shown it can have an impact on results.
Czeisler found that circadian rhythms could be altered from 22 hours to 28 hours just by using dim artificial lighting.
Explain Siffre (1962) cave study
AIM - to see what his natural sleep wake cycle was when deprived of external environmental cues
PROCEDURE - Siffre spent two months in a cave in the French Alps with no natural light. he had no clock to check the time. The absence of natural light allowed his biological clock to run at its natural rate
The findings were that his sleep-wake cycle settled naturally at around 25 hours. This supports an innate, biologically determined circadian rhythm because he maintained this rhythm in the absence of external zeitgebers.
Describe Maguire et Al’s taxi study (2000)
- MRI scans of 16 licensed male London taxi drivers who had studied for ‘the knowledge’ (learning all the streets and routes of London) were compared with 50 matched controls who had never driven taxis
-> significantly more grey matter in right posterior hippocampus in the taxi driver group compared to control
-> additionally, the increased size was relative to the length of time the taxi driver had been working
Describe Sperry’s (1968) research into hemispheric lateralisation
Sperry studied 11 split brain patients who had undergone surgery to sever the corpus callosum as a medical treatment for severe epilepsy.
- an image or word was quickly projected to the patient’s right visual field (which is processed by the left hemisphere), another image was projected to the left visual field (processed by the right hemisphere).
- In a split-brain patient, information cannot be transmitted from one hemisphere to another, so the effects of this was studied.
Findings:
When a picture was shown to the right visual field, the patient could describe it easily. When the image was shown to the left visual field, the patient found it difficult to describe it, or couldn’t see anything there.
- This is likely due to the lack of language processing ability in the right hemisphere.
- The left hemisphere was unable to receive the information due to the separation of the hemispheres.
Part 2 involved a ‘tactile’ task where an object that they couldn’t see was placed in their right or left hand and the participant had to describe what they felt. When the object was in their right visual field, they could describe it, when the object was in their left visual field they couldn’t describe it.
Part 3 was a drawing task where participants were presented with a picture in either their left or right visual field. Hey then had to simply draw what they saw. When the image was presented to the left hemisphere, they could draw it easily, when the image was presented to the right hemisphere, the image was never as clear
-> this concluded that the left hemisphere is responsible for language while the right hemisphere is responsible for visual-motor skills eg. drawing
Summarise Broca’s research (1861)
- studied a patient named Tan, who could only say the word “tan” but could understand speech perfectly. After Tan’s death, Broca carried out a post mortem to examine his brain and found a lesion in the left frontal lobe (now known as Broca’s area), linking it to speech production difficulties.
-> supports localisation theory
Summarise Wernike’s research (1874)
- Karl Wernicke studied patients with fluent but nonsensical speech, now known as Wernicke’s aphasia.
- He discovered that damage to the left temporal lobe (now known as Wernicke’s area) caused issues with speech comprehension
Summarise Phineas gage (1848) incident
- was a railroad construction foreman who survived a severe brain injury from an iron rod that went through his skull, and damaged his frontal lobe.
- he survived, but faced personality changes: he became short-tempered and irritable after once being known as a hard working, pleasant man.
- suggesting that mood regulation may be the responsibility of the frontal lobe.
-> supports localisation theory
Evaluate Sperry (1968) split brain research
✅ lab study so scientific and objective
✅ • Luck et al. 1989 - Split-brain participants were faster at identifying the odd one out from visual tasks than controls (twice as fast)-> Supports that Left brains and right brains are distinct in terms of functions and abilities
✅ Broca supports localisation theory
❌ Michael Gazzaniga (1998) - patient J.W developed the ability to speak from his right hemisphere
❌ Lashley (1950) holistic theory rats study
❌ small sample size, all epileptic patients and control contained no epileptic patients so differences in results could be caused by this
❌ the disconnection between hemispheres was greater in some individuals
