Showing posts with label Paranormal. Show all posts
Showing posts with label Paranormal. Show all posts

Thursday, March 18, 2010

Explaining Ghost Sightings (Part 2 – Temporal Lobe Epilepsy)

When I said that pareidolia can explain a lot of ghost sightings, I didn’t mean all of them. Sometimes the environment is bright and clear, you’re fully awake, and yet you still get that “ghostly” feeling. Scary, eh? Well, that may just be a hallucination, and here I shall tackle a common cause for hallucinations – temporal lobe epilepsy.

Defining Temporal Lobe Epilepsy

Temporal Lobe Animation

The temporal lobe would be the part in red. Only the left temporal lobe is shown.

The temporal lobe is separated into 2 parts: right and left. It’s responsible for auditory processing, processing of semantic & lexical information in speech, and long-term memory. On the other hand, epilepsy aka seizure disorder is a common neurological disorder that causes recurrent & unprovoked seizures in patients. These seizures happen when clusters of neurons fire excessively/abnormally/synchronously. Combine these two, and you’ve got temporal lobe epilepsy.

Temporal lobe epilepsy causes simple and complex partial seizures. Simple partial seizures simply cause unusual behaviours and patterns of cognition, including hallucinations and paranormal experiences; complex partial seizures can render the patient disabled and lose awareness temporarily. If one is unlucky though, it may spread and become a tonic–clonic seizure, a type of seizure that affects the entire brain, and is much more lethal.

Causes

Temporal lobe epilepsy may be caused by a variety of factors, including:

1. Hippocampal sclerosis, which is present in 2/3 of patients, and causes mesial temporal lobe epilepsy (MTLE).
2. Infections
3. Febrile seizures
4. Malignancies
5. Vascular malformations
6. Idiopathic (genetic), but it’s rare.
7. Trauma producing contusion/haemorrhage that results in encephalomalacia or cortical scarring
8. Difficult traumatic delivery such as forceps deliveries
9. Hamartomas

Symptoms Related to Ghost Sightings/Paranormal Experiences

Since the temporal lobe is responsible for hearing, information processing, and long-term memory, abnormal functioning in the temporal lobes will also cause these brain processes to function wrongly. Complex partial seizures are unrelated to ghost sightings, so I’ve decided not to write about them.

Simple Partial Seizures/Auras

Just to make it clear, the word “aura” in this context is defined as a “warning” before “a complex partial seizure occurs, not the pseudoscientific human/soul aura or whatever it’s called. For patients with temporal lobe epilepsy, they may have a simple partial seizure, which creates an aura, and usually leads to a complex partial seizure.

Somatosensory and Special sensory phenomena

Auras may come in the form of olfactory, gustatory, auditory, and visual hallucinations and illusions. Auditory hallucinations consist of a buzzing sound, a voice/voices, or muffling of ambient sounds. On the other hand, visual hallucinations may take the form of distortions of shape, size, and distance of objects, shrinking (micropsia) or enlarging of things (macropsia), and also tilting of structures.

Psychic Phenomena

Patients may also feel déjà vu, the feeling that’s you’ve seen something before, although you’ve not, and jamais vu, in which one suddenly feels eerie and unfamiliar to the environment, although he/she has been in the same situation before, and he/she knows it.

Patients may also experience depersonalization (feeling of detachment from oneself) or derealisation (surroundings appear unreal). “Out of body” experiences can also happen to the patient, a phenomenon known as dissociation/autoscopy. Plus, if the seizure arises from the amygdala, the patient will become fearful and anxious, sometimes to the point of having “an impending sense of doom”.

Deja vu

Conclusion

Here, I’ve shown that so-called ghost sightings may be caused by temporal lobe epilepsy instead of a real ghost appearing, which goes against Occam’s razor and science too much (violation of the laws of physics, anyone?)

However, I am aware that not everyone has temporal lobe epilepsy, yet many still experience its symptoms. There’s another similar cause for such experiences – electromagnetic disruption of the temporal lobe, and it’s one that I shall address next.

Tuesday, March 16, 2010

Explaining Ghost Sightings (Part 1 – Pareidolia)

During a debate with my friend on the existence of the soul, he raised ghost sightings as an argument for the soul’s existence. While I quickly refuted his argument, it led me to consider writing a naturalistic explanation for ghost sightings, since they’re frequently used when spiritualists argue against naturalists. I’ll start with pareidolia, a common psychological/neurological phenomenon.

What's Pareidolia?

Did your friends ever said to you: “I saw a ghost when I was walking to the toilet with my own eyes”? Or have you ever heard someone calling your name, but there’s no one around? Meet pareidolia, the tendency to interpret a vague stimulus as something known to the viewer; such as interpreting marks on Mars as canals or seeing shapes in clouds.This phenomenon is extremely common, and can be created easily. Lets see….

Alien on Mars

That's an alien on Mars...... or is it?

Alien or Tree?

That may be an alien disguising as a tree sticking its tongue towards us... Yeah that's obvious.

Evil Spirit in Womb

In addition to the ghostly female face, I also see the head of an avian-like monster beside the face, and a ghost with eyes, hands and a mouth at the centre-right of the 1st image. Something’s definitely wrong, or I simply have a great imagination.

I bet you saw the faces. And if you did, congratulations, for you're a normal human, and like all of us, susceptible to illusions and pareidolia. So if you see a ghostly apparition, don't worry - it's your mind seeing an image that vaguely resembles something you’re familiar with, in which your brain then exaggerates and modifies to be clearer.

Conditions that Cause Pareidolia

Vague Stimuli (Blurry Images/Sounds)

The brain is a gifted interpreter – it’s capable of responding to blurry face-like images and interpreting them rapidly – in fact this study suggests that it takes only 165ms for our ventral fusiform cortex to be activated, compared to 130ms for a true face. This study shows that pareidolia is an instinctive response, and not a late cognitive reinterpretation phenomenon.

Despite that, our first instincts are often wrong, and when the same object is looked more carefully and with more detail, it’s often revealed that the so-called “ghost” is an illusion after all. The best example for this would be the “Face of Mars” in the Cydonia region.

Face on Mars by Viking

Here's part of the Cydonia region, taken by the Viking 1 orbiter and released by NASA/JPL on July 25, 1976. And yes, that's the so-called face of Mars near the top.

Upon seeing the “face”, conspiracy theorists claimed that it was “intelligently designed” by Martians, and that it was located next to a city whose temples and fortifications could be seen. On the other hand, NASA and the skeptics explained that it was simply the effects of light, but the conspiracy theorists took that as a sure sign of a cover up. Until the high-res images appeared.

Face on Mars by MRO

High resolution Mars Reconnaissance Orbiter (2006-present) image of the "Face on Mars". Taken using the onboard HiRISE camera.

Similar high-res images were took by the NASA’s Mars Global Surveyor (1997-2006) and the European Space Agency's Mars Express probe (2003-present). All wild speculations about the “face of Mars” were put to rest, and the conspiracy theorists went silent (if not embarrassed). However, this is not the first case of pareidolia caused by vague stimuli, and will certainly not be the last.

Examples of pareidolia inducing environments (happens especially, if not only at night):

1. Half-lit hallways.
2. Toilets.
3. Dorms.
4. Camping sites.
5. Highways.
6. Quiet parks.

When You're Half-conscious

Sometimes, the stimuli doesn’t have to vague/blurry -  pareidolia can also happen when you’re aren’t fully self-aware (half awake, fatigued, sleepy etc). When we’re not fully conscious, our brains tend to misinterpret things, and pareidolia can occur easily. That’s why ghosts love to come out at night, or when you’re working overtime, or when you wake up at night. Yeah, makes perfect sense.

Evolutionary Origins of Pareidolia

Since pareidolia is literally hardwired into our brains, there must be a evolutionary advantage for our brains to see "faces" or hear "voices" when there are none. A plausible explanation is the false-alarm hypothesis (or whatever it’s called).

The False Alarm Hypothesis

Let's assume that there're 2 individuals, A & B living in the wilds of yesteryear. A is able to respond to familiar stimuli (faces, animal voices) quickly, but is susceptible to pareidolia; B doesn't respond as well, and thus never have any false alarms. In the prehistoric world (perhaps even in the modern world), A would be much more likely to survive by recognizing familiar patterns quickly, and escape on the first sign of a threat. Even it was a false alarm, it wouldn't affect  A negatively. B, on the other hand, failing to recognize patterns quickly, would be less self-aware, and fall prey to sabre-tooth tigers easily.

On a not-so related side note, I propose that we fear ghosts because they look so damn similar to the predators our ancestors had to escape from at night – blurry, vaguely resembling things we’re familiar with, making all sorts of noises, and yes, their ghastly eyes. Those who were afraid of the predators survived, while the others left offspring. Thus, when we see similar images in our lives, we still invoke a “fight or flight” response and get freaked out.

Conclusion

Here, I’ve put forward pareidolia as the first of my explanations for ghostly encounters, and there’s going to more. I just hope that my friends would try and take a look at my explanations, instead of simply repeating the same-ol’ argument every time. I bet they won’t though.

How about you, my fellow readers? Do you think that pareidolia manages to explain some, if not most ghost sightings? If it can’t, then why is it so?