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Do Blind People See Things in Their Dreams?

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A question from reader Josiah: "Do blind people see when they dream? I think there are two sides to the question, dealing with people who were born blind, and those who used to be able to see."


Whether visual imagery is present in the dreams of the blind has been pondered by scientists since the early 19th century. Josiah is right about that last part. People who are sighted, people who were born sighted but were blinded later in life, and people who were born blind all dream differently. As the Royal National Institute of the Blind in London puts it, "Dreams are experienced in the same way as life is lived." (Some people over 55 occasionally dream in black and white, while younger people who grew up with color television tend to dream only in color.1) How much visual imagery someone has experienced in their waking life—if they've experienced it at all—affects how much visual imagery is in their dreams.

A series of questionnaire and interview studies conducted in the 1970s2 led to four generalizations about the dreams of the blind:

1. People born blind, and who never experienced visual imagery in waking life, have no visual images in their dreams.

2. People who became blind before the age of five rarely experience visual imagery in their dreams.

3. People who became blind between the ages of five and seven sometimes retain some visual imagery and experience it in their dreams.

4. Most people who became blind after the age of seven continue to experience at least some visual imagery in their dreams, but the clarity and frequency of the imagery is often reduced with time.

Several studies in sleep laboratories, in which blind participants were woken up during REM sleep for the collection of dream reports, reported similar results.

A more recent study3 analyzed a sample of 372 dreams from 15 blind adults—some born blind, and others who went blind later in life. Again, the study found that people blind since birth or very early childhood experienced no visual imagery, and people blinded later in life did retain some visual imagery from their sighted waking lives and experienced it while dreaming.

One participant in the study, though, reported visual imagery inconsistent with the trends described in previous findings. Participant 13, a 24-year-old man blinded at age four, reported that he was able to see objects "clearly" or "plainly" during the dream, so it is possible that some people who became blind before the age of five can experience visual imagery in dreams.

The study also expanded upon the previous research and revealed two interesting things:

1. While less than one percent of sighted participants surveyed in two previous studies reported experiencing gustatory, olfactory, or tactual sensations in dreams, all but three of the blind participants in this study reported experiencing them. One participant, who has been blind since birth, reported that 48 percent of the sensations in his dreams were auditory and the other 52 percent were a mix of taste, smell and touch sensations.

2. Sixty percent of the blind men's dreams that involved locomotion or transportation, and 61% of the blind women's, had at least one incident of "dreamer-involved misfortune" (the norms for sighted men and women are 31 percent and 28 percent, respectively), which the researchers hypothesize is a continuation of the waking-life concerns that the blind have about getting from place to place.

1 Murzyn E. (2008). Do we only dream in colour? A comparison of reported dream colour in younger and older adults with different experiences of black and white media. Consciousness and cognition. Dec;17(4):1228-37.
2 Kirtley, D. (1975). The psychology of blindness. Chicago: Nelson-Hall.
3 Hurovitz, C., Dunn, S., Domhoff, G. W., & Fiss, H. (1999). The dreams of blind men and women: A replication and extension of previous findings. Dreaming. 9:183-193.

[Image courtesy of Christophe Moustier.]

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Big Questions
What Is the Difference Between Generic and Name Brand Ibuprofen?
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What is the difference between generic ibuprofen vs. name brands?

Yali Friedman:

I just published a paper that answers this question: Are Generic Drugs Less Safe than their Branded Equivalents?

Here’s the tl;dr version:

Generic drugs are versions of drugs made by companies other than the company which originally developed the drug.

To gain FDA approval, a generic drug must:

  • Contain the same active ingredients as the innovator drug (inactive ingredients may vary)
  • Be identical in strength, dosage form, and route of administration
  • Have the same use indications
  • Be bioequivalent
  • Meet the same batch requirements for identity, strength, purity, and quality
  • Be manufactured under the same strict standards of FDA's good manufacturing practice regulations required for innovator products

I hope you found this answer useful. Feel free to reach out at www.thinkbiotech.com. For more on generic drugs, you can see our resources and whitepapers at Pharmaceutical strategic guidance and whitepapers

This post originally appeared on Quora. Click here to view.

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Health
8 Potential Signs of a Panic Attack
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It's not just fear or worry. In fact, many panic attacks don’t look like panic at all. Panic attacks come on rapidly, and often at times that don't seem to make sense. The symptoms of panic disorder vary from person to person and even from attack to attack for the same person. The problems listed below are not unique to panic attacks, but if you're experiencing more than one, it's a good idea to talk to your doctor either way.

1. YOU'RE DIZZY.

Doctors sometimes call the autonomic nervous system (ANS) the "automatic nervous system" because it regulates many vital bodily functions like pumping blood all on its own, without our having to think about it. Panic attacks often manifest through the ANS, leading to increased heart rate or decreased blood pressure, which can in turn lead to feeling lightheaded or faint.

2. YOU'RE LOSING YOURSELF.

Feeling detached from yourself is called depersonalization. Feeling detached from the world, or like it's fake or somehow unreal, is called derealization. Both forms of dissociation are unsettling but common signs that a panic attack has begun.

3. YOU'RE QUEASY.

Our digestive system is often the first body part to realize that something is wrong. Panic sends stress hormones and tension to the gut and disrupts digestion, causing nausea, upset stomach, or heartburn.

4. YOU FEEL NUMB OR TINGLY.

Panic attacks can manifest in truly surprising ways, including pins and needles or numbness in a person's hands or face.

5. YOU'RE SWEATY OR SHIVERING.

The symptoms of a panic attack can look a lot like the flu. But if you don't have a fever and no one else has chattering teeth, it might be your ANS in distress.

6. YOU KNOW THE WORST IS COMING.

While it may sound prophetic or at least bizarre, a sense of impending doom is a very common symptom of panic attacks (and several other conditions). 

7. BREATHING IS DIFFICULT.

The ANS strikes again. In addition to the well-known problems of hyperventilation or shortness of breath, panic attacks can also cause dyspnea, in which a person feels like they can't fill their lungs, and feelings of choking or being smothered.

8. YOU'RE AFRAID OF HAVING A PANIC ATTACK. 

Oddly enough, anxiety about anxiety is itself a symptom of anxiety and panic attacks. Fear of losing control or getting upset can cause people to avoid situations that could be triggering, which can in turn limit their lives. 

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