Psych Case Readings Quiz

One brain or two: Who were the researchers?

Roger Sperry and Michael Gazzaniga

One brain or two: Who were the subjects?

Patients who had undergone split brain surgery

One brain or two: What happened in the case?

• Sperry and Gazzaniga studied patients who had undergone surgery that severed the bundle of nerves that connect the two brain hemispheres (corpus collosum)

• The procedure was done to treat severe epilepsy

• The researchers conducted experiments to test how each hemisphere of the brain processes information differently. 

One brain or two: What are some examples of what researchers did for the experiments?

• When an image was shown to the left visual field (processed by the right hemisphere), the patient could not verbalize what they saw but could draw or select the object with their left hand.

• When the image was shown to the right visual field (processed by the left hemisphere), patients could name the object because the left hemisphere controls language.

One brain or two: Why is the case significant?

• The case showed that both hemispheres of the brain have different functions.

• It provided strong evidence that conscious awareness is divided between the hemispheres.

One brain or two: What are the two hemispheres of your brain responsible for?

• Your left brain is better at speaking, writing, mathematical calculations, reading, and is the primary language center.

• Your right brain is better at recognizing faces, solving problems involving spatial relationships, symbolic reasoning, and artistic activities

One brain or two: What does the increased knowledge of the two hemispheres allow for?

Better treatments of stroke or head injury patients

More experience=Bigger brain?: Who were the researchers?

Mark Rosenzweig, David Krech, Edward Bennett, and Marian Diamond

More experience=Bigger brain?: Who were the subjects?

Laboratory rats in a controlled environment

More experience=Bigger brain?: What happened in the case?

• Researchers placed rats into two different environments, either an enriched environment or an impoverished environment.

• In the enriched environment, there were other rats, toys, tunnels, and opportunities for physical activity and social interaction.

• In the impoverished environment, the rats were isolated in bare cages without toys or other rats. 

• The rats lived in these conditions for weeks, and after their brains were examined. 

More experience=Bigger brain?: What did the different groups of rats show?

• The enriched rats showed: A thicker cerebral cortex, heavier brains, greater activity of the acetylcholinesterase (a chemical important for learning), and a greater amount of glial cells.

• The impoverished rats showed: A thinner cerebral cortex, lighter brains, fewer synaptic connections, lower levels of acetylcholinesterase, fewer glial cells, and less brain growth overall.

More experience=Bigger brain?: Why is the case significant?

• The case provided biological evidence that the environment affects brain development. 

• It demonstrated neuroplasticity, which is the brain's ability to change based on experience, even in adulthood.

• Challenged the idea that the brain is based solely on genetics.

• Suggested that stimulating environments may enhance intellectual development.

• Showed that behavior and environment can influence brain anatomy.

The Man With No Brain: Who were the researchers?

John Lorber 

The Man With No Brain: Who were the subjects?

Individuals with severe hydrocephalus, in particular a university student whose CAT scan showed extremely reduced brain tissue

The Man With No Brain: What happened in the case?

• Lorber examined brain scans (CAT scans) of patients with hydrocephalus. 

• In one dramatic case, a math student (IQ ~ 126) was found to have “virtually no brain”.

• The scan appeared to show that 95% of his cranial cavity was filled with cerebrospinal fluid, leaving only a thin layer of brain mantle (1 mm or so). 

• Despite this, the student was relatively functional: academically successful, able to live a “normal” life. 

The Man With No Brain: What did these findings show?

• Lorber interpreted the case to suggest that much of the brain might be “redundant” (spare capacity) and that the nervous system might rewire or adapt remarkably to damage or reduction over time.

• However, later critiques note that the apparent reduction might partly reflect compaction of brain matter rather than outright loss, and that imaging limitations of the time make interpretation uncertain. 

The Man With No Brain: Why is the case significant?

• It is a striking example of brain plasticity and the ability of the brain (or nervous system more broadly) to adapt even with extremely reduced “normal” structure.

• It challenges simplistic assumptions about brain volume → cognitive ability (i.e. more brain always equates to higher function).

• Raises questions about localization of function vs distributed processing: how “necessary” are different brain regions?

• It’s often cited in debates about reserve capacity, neural compensation, and how much redundancy the brain might have.

• Also underscores the importance of technological limits and interpretive caution: what appears in scans might not tell the full story of underlying neural structure or function.

The Man Who Lived With A Hole In His Head: The Story Of Phineas Gage: Who are the researchers?

Dr. John Harlow (treated and documented his recovery), later analyzed by researchers and psychologists

The Man Who Lived With A Hole In His Head: The Story Of Phineas Gage: Who are the subjects?

Phineas Gage

The Man Who Lived With A Hole In His Head: The Story Of Phineas Gage: What happened in the case?

• In 1848, Gage was working on a railroad in Vermont.

• While packing gunpowder into a rock with a tamping iron, a spark caused an explosion.

• A 3½-foot-long iron rod (over 13 lbs) shot through his left cheek and out the top of his skull, destroying much of his left frontal lobe.

• Amazingly, he survived, could walk and talk soon after, and recovered physically.

The Man Who Lived With A Hole In His Head: The Story Of Phineas Gage: How did the accident change Gage?

• Before the accident: Gage was described as responsible, hardworking, polite, and well-liked.

• After the accident: Reports say he became rude, impulsive, unreliable, and inappropriate.

• He reportedly couldn’t hold a steady job.

• His personality changed so drastically that people said he was "no longer Gage."

The Man Who Lived With A Hole In His Head: The Story Of Phineas Gage: Why was the case significant?

• First clear evidence linking frontal lobe function to personality, behavior, and decision-making.

• Supported the idea of localization of brain function — that specific parts of the brain control specific psychological processes.

• Suggested that damage to the frontal lobe impairs emotional regulation, impulse control, and judgment.

• Laid early groundwork for the modern field of neuropsychology.

The twins case: David Reimer, The Boy Who Was Never A Girl: Who were the researchers?

Dr. John Money

The twins case: David Reimer, The Boy Who Was Never A Girl: Who were the subjects?

David Reimer (born Bruce Reimer)

The twins case: David Reimer, The Boy Who Was Never A Girl: What happened in the case?

• Bruce Reimer suffered a botched circumcision that destroyed his penis.

• His parents consulted Dr. John Money, who believed gender identity is learned (nurture over nature).

• Money advised them to raise Bruce as a girl, renamed Brenda

• Dr. Money reported the case as a success, claiming it proved gender identity was socially constructed.

• However, Brenda never identified as female

• She experienced severe emotional distress, social difficulties, and identity confusion

• At age 14, she was told the truth and chose to re-transition to male, taking the name David

• David later married and tried to live a normal life, but continued to suffer psychologically

• David died by suicide in 2004

The twins case: David Reimer, The Boy Who Was Never A Girl: Why was the case significant?

• Initially used to support the idea that gender identity is entirely learned, but the eventual outcome strongly contradicted that claim

• Provided powerful evidence that biology plays a key role in gender identity

• Challenged extreme nurture-based theories of gender development

• Sparked major ethical debates in psychology and medicine, such as informed consent, deception, and long-term harm in research