1. Near Death Experiences
Common Experiences
Physical trauma
Feeling of floating
See your body from outside, i.e., above and looking down
Sense of euphoria, calm, etc.
Begin moving/travelling
Tunnel
Meet deceased people
Normally in perfect condition – no physical deformities
Meet religious figures
Return to your body
Afterwards, the subject is likely to make life-changing choices

2. Factors for Consideration
Physical conditions
Usually the body is physically drained – weak
Brain may be suffering from oxygen shortage or even complete lack of oxygen
Though not always
Brain may have high levels of carbon dioxide
Body may be filled with painkillers or anesthesia

3. Hallucination or Real Experience?
Arguments it is real
Subjects insist the event felt very real to them, not a hallucination
Similar stories are told by people from different cultures
“Tunnel” is an almost universal feature
Accurate description of events that occurred while patient is unconscious
Accurate descriptions of words, procedures, etc. during surgery
Rarely, accurate views of objects not visible to the patient
Outside views from hospital, for example
Argument it is a hallucination
Details vary by culture
Christians meet Jesus; Buddhists meet Buddha
Some events are not accurate descriptions
Detailed but incorrect descriptions of what people look like

4. Tunnel Vision How can we account for the tunnel experience?
Under conditions of low oxygen, the senses cease to function properly
For sight, the effect is that the peripheral vision is lost first, and the central portion last
Example – after I exercise
Dehydrated – low blood pressure
Drive home from health club
Stand and my vision becomes tunnel vision
Different senses are affected differently under conditions of low oxygen or anesthesia
Sight is lost before hearing
Not uncommon that people can still hear when they are completely blind

5. Other Common Aspects of Stories
Many similarities to dreaming
Very common to see deceased people in dreams
My sister, my parents
Many of these people lack physical deformities that they had in life
My sister is usually not blind in my dreams
Floating and flying
These are common features in my dreams – how about yours?
Religious themes
Even people who are not religious often see religious figures
Nonetheless, we are all culturally aware of religions themes
My nightmare
Seeing your body from outside
For true memories, we tend to picture things in first person
When we reconstruct memories, we tend to view them in third person

6. Reminder – How Memory Works
How can we explain often accurate descriptions of events?
Recall how memory works
An initial event occurs
This gets recorded as an engram
You later recall the information, and reconstruct the event in your mind
You repeat this over many cycles
Eventually, you can’t distinguish between which aspects are real and which were reconstructed
Those who have experienced trauma tend to have incomplete and confusing memories
When they recall it, they try to assemble it into a coherent whole
Over time, their stories become a single consistent narrative
Initial Source
Engram
Recall
Engram
Recall

7. How to Account for Information
How can we account for the accurate information later?
Description of information by people later, etc.
Recall, we are better at remembering data than what its source is
Source confusion
Lucky guesses and logical deductions
Most of us have some idea of what surgery looks like
And often, many details of these descriptions are inaccurate
Under-anaesthetized patients
It is not uncommon for patients to wake up during surgery
Fortunately, we usually don’t remember this
Hearing is the last sense to go
Common for people to correctly report exact words spoken by doctors in surgery

8. Distinguishing Reality from Fantasy
How do we distinguish memories from fantasies?
Both real events and imagined events produce engrams
Some clues that events are real are:
The event is connected with other events you know are real
People who experienced severe trauma did have real trauma
Seeing things from third-person vs. first-person perspective
But near death experiences are normally out of body (of course)
Real events get confirmed by those around us
But since they are partly reconstructed from real events, such confirmation is not surprising

9. The Effects of Drugs Most of these people are drugged
Some of the effects of drugs include:
Perception that the world is shrinking or enlarging
This can account for the sense of motion
Age regression
Brings back old memories
Hallucinations
Euphoria/sense of calm

10. A Single Coherent Picture?
Can we put together a single coherent picture of these stories?
Patients have real memories of things said or done, or even seen during surgery
They also have information given to them after the fact by their doctors and visitors
And some idea what was involved
They also may have experienced
Tunnel vision
Hallucinations
Dreams
These all form engrams which they combine to make a coherent story
At first possibly incomplete, but over time it becomes more complete

11. Artificially Induced Near Death Experiences
Scientists have found that out of body experiences can be induced by stimulating the right temporoparietal junction of the brain
This portion of the brain is responsible for joining together all your senses into a single coherent view of “self”
Hormones released during extreme stress can cause feelings of euphoria
Dopamine, which is released in traumatic situations, can also cause hallucinations

12. In Summary
There are many accounts of near death experiences, from many cultures
They have similarities, but some differences, that presumably represent cultural differences
When you read popularized accounts of these events, they are rarely done from an objective viewpoint
Only the most remarkable stories tend to be published
Only the “hits” tend to be recorded, not the “misses”
It is impossible to analyze statistically/scientifically, because of the difficulty of reproducing results
Any failures can be rationalized as hallucinations, while successes are touted as proof