IB Psych Biological Approach - Studies/People

Paul Broca (1861)

The case of “Tan” - found that the loss of articulate speech (aphasia) was linked to damage in the left side of the brain, known as Broca’s area, first anatomical proof of cerebral localization of function

Karl Lashley

performed surgical experiments on rats to locate the “engram” or the physical seat of memory, he also trained rats in mazes and removed parts of their cortex and discovered that memory is not stored in one specific area - opposed the idea of strict localization

proposed mass action, the impairment of function depends on how much cortex is removed, and equipotentiality, if one part of the cortex is damaged others will take over it’s functions

Roger Sperry

demonstrated that left and right cerebral hemispheres have distinct, specialized cognitive roles, left hemisphere is dominant for language, speech, and analytical processing while the right is dominant for non verbal processing, spatial tasks, and visual recognition, proved that high level cognitive functions are localized and lateralized (meaning certain parts of the brain are responsible for specific functions)

Michael Gazzaniga

did split-brain research with Roger Sperry, further demonstrated that the two sides of the brain work independently and also discovered that the left-brain has an “interpreter” module which attempts to make sense of the world by constructing explanations for behavior even when information is incomplete

Sharot et al (2007)

aim

• the researchers wanted to investigate the potential biological factors in the creation of flashbulb memories

  • highly vivid and long lasting memories of a shocking event

procedure

• study included 24 individuals from NYC who were present during 9/11, conducted 3 years after the attacks

• it was a quasi-experiment, IV: location of participant during 9/11, DV: memory of the events

• participants were placed in an fMRI and shown word cues on a screen to prompt either memories of 9/11 (direct/emotional) or memories from the summer before (control/baseline)

  • while the memories were being recorded the researchers recorded information about the amygdala

findings

• Participants who were downtown (closer to World Trade Center) showed higher amygdala activation when recalling 9/11 compared to when recalling the previous summer

• Participants who were further away showed equal levels of response in the amygdala when recalling both events

• concluded that close personal experience is critical for forming vivid flashbulb memories

limitations

• the study is correlational, sample size was small and only from the US making it hard to generalize

Saxe and Kanwisher (2003)

aim

• to find out if there is a specific area of the brain that is dedicated to Theory of Mind (cognitive ability to understand that other people have beliefs, desires, intentions, and perspectives that are different from one's own)

  • also wanted to determine if this region is distinct from areas involving general social processing or language

procedure

• labratory experiment with fMRI scanning

• Participants were placed in an fMRI and asked to read different types of stories

  • false stories (about someone holding an incorrect belief)

  • True-belief stories

  • Physical stories (about outdated physical representations, like an old photograph or map)

• after reading each story patients answered comprehension questions

• Researchers measured blood oxygen level dependant (BOLD) signals to see which brain areas were activated during each condition

• Brain activation during belief reasoning was compared to activation during non-mental reasoning

findings

• when participants reasoned about false beliefs compared to true beliefs or physical representation the right temporo-parietal junction has significantly greater activation

  • activation was highly selective, did not respond strongly to general social information or language processing

• results suggest that rTPJ localizes the ability to tell whether someone is wrong and is associated with Theory of Mind and understanding other’s beliefs

limitations

• sample size was small, correlation was proven not causation, lab environment could reduce ecological validity

Maguire et al (2000)

aim

• to investigate if spatial navigation experience is associated with structural changes in the hippocampus

procedure

• quasi experiment using MRI scans, IV: taxi drivers vs. bus drivers DV: volume of the hippocampus

• 55 male volunteers, 18 were London taxi drivers

• structural MRI scans were taken to measure the density of grey matter in the brain

findings

• taxi drivers had increased grey matter in the posterior hippocampus while they had reduced grey matter in the anterior hippocampus

  • posterior hippocampus specializes in spatial navigation and detailed memory retrieval, showing that taxi drivers are good at storing memories

    • supports localization of function because it demonstrates that the posterior hippocampus is specialized for storing and navigating spatial information

  • anterior hippocampus specializes in encoding new memories, showing that taxi drivers had trouble creating new memories

• the longer the taxi-driving experience, greater the posterial hippocampus volume

limitations

• sample was all male and from London, not very generalizable, correlational

Draganski et al (2004)

aim

• to investigate whether learning a new motor skill can produce measurable changes in brain structure

procedure

• 24 volunteers, 21 female and 3 male, aged 20-24, and all non-jugglers

• participants were randomly allocated into two groups: jugglers and non-jugglers (control)

• a baseline scan was done for both groups, then the jugglers were taught a 3 ball routine and asked to practice until mastery of the skill

• 3 months after the first scan another scan was done, then jugglers were instructed to stop practicing for 3 months

• scan 3 was performed 3 months after the second scan, MRI scans were then analyzed for differences in grey matter

findings

• In the 2nd scan jugglers showed signficantly more grey matter in the mid-temporal area of both hemispheres

  • mid-temporal area specializes in processing visual motion, essential for tasks that require tracking moving objects in space

    • supports the idea of functional specialization, because the brain region responsible for processing motion became structurally enhanced when it was repeatedly and intensively used

• in the 3rd scan the amount of grey matter in the mid-temporal area decreased but remained higher than baseline scan

  • shows experience dependant neuroplasticity

• control group showed no change

limitations

• small sample size and mostly female, effects were very short term

Merzenich et al (1984)

aim

• to investigate whether the somatosensory cortex is capable of reorganizing itself after sensory loss

procedure

• controlled animal experiment with adult monkeys

• researchers first mapped the monkeys somatosensory cortex using microelectrode recordings to identify which cortical neurons responded to simulation of each finger

• the sensory input from one or more fingers was removed (either by amputation or severing sensory nerves) creating a region of cortex that no longer received its normal input

• after a period of recovery, cortical maps were recorded again to see how the brain responded to the loss of sensory input

findings

Paul Bach-y-Rita

Thaler, Arnot and Goodale, 2011

Crockett et al (2010)

Fisher, Aron and Brown (2005)

Freed et al (2001)

Draganski (2006)

Romero et al (2014)

Kosfeld et al (2005)

Scheele et al (2012)

De dreu et al (2012)

Lundstrom and Olsson (2005)

Hare et al (2017)

Cutler, Friedmann and McCoy (1998)

McCoy and Pitino (2002)

Kendler et al (2015)

Bouchard and McGue (1981)

Scarr and Weinberg (1983)

The Adolescent Adoption Study

The Transracial Adoption Study

Weaver et al (2004)

Miller et al (2009)

McGowan et al (2009)

Kaminsky et al (2008)

Curtis, Aunger and Rabie (2004)

MacLean (1990)

Premack (2007)

Romero (2014)