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Do Blind People See Things in Their Dreams?

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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New Patient Test Could Suggest Whether Therapy or Meds Will Work Better for Anxiety
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Like many psychological disorders, there's no one-size-fits-all treatment for patients with anxiety. Some might benefit from taking antidepressants, which boost mood-affecting brain chemicals called neurotransmitters. Others might respond better to therapy, and particularly a form called cognitive behavioral therapy, or CBT.

Figuring out which form of treatment works best often requires months of trial and error. But experts may have developed a quick clinical test to expedite this process, suggests a new study published in the journal Neuropsychopharmacology.

Researchers at the University of Illinois at Chicago have noted that patients with higher levels of anxiety exhibit more electrical activity in their brains when they make a mistake. They call this phenomenon error-related negativity, or ERN, and measure it using electroencephalography (EEG), a test that records the brain's electric signals.

“People with anxiety disorders tend to show an exaggerated neural response to their own mistakes,” the paper’s lead author, UIC psychiatrist Stephanie Gorka, said in a news release. “This is a biological internal alarm that tells you that you've made a mistake and that you should modify your behavior to prevent making the same mistake again. It is useful in helping people adapt, but for those with anxiety, this alarm is much, much louder.”

Gorka and her colleagues wanted to know whether individual differences in ERN could predict treatment outcomes, so they recruited 60 adult volunteers with various types of anxiety disorders. Also involved was a control group of 26 participants with no history of psychological disorders.

Psychiatrists gauged subjects’ baseline ERN levels by having them wear an EEG cap while performing tricky computer tasks. Ultimately, they all made mistakes thanks to the game's challenging nature. Then, randomized subjects with anxiety disorders were instructed to take an SSRI antidepressant every day for three months, or receive weekly cognitive behavioral therapy for the same duration. (Cognitive behavioral therapy is a type of evidence-based talk therapy that forces patients to challenge maladaptive thoughts and develop coping mechanisms to modify their emotions and behavior.)

After three months, the study's patients took the same computer test while wearing EEG caps. Researchers found that those who'd exhibited higher ERN levels at the study's beginning had reduced anxiety levels if they'd been treated with CBT compared to those treated with medication. This might be because the structured form of therapy is all about changing behavior: Those with enhanced ERN might be more receptive to CBT than other patients, as they're already preoccupied with the way they act.

EEG equipment sounds high-tech, but it's relatively cheap and easy to access. Thanks to its availability, UIC psychiatrists think their anxiety test could easily be used in doctors’ offices to measure ERN before determining a course of treatment.

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Food
A Pitless Avocado Wants to Keep You Safe From the Dreaded 'Avocado Hand'
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The humble avocado is a deceptively dangerous fruit. Some emergency room doctors have recently reported an uptick in a certain kind of injury—“avocado hand,” a knife injury caused by clumsily trying to get the pit out of an avocado with a knife. There are ways to safely pit an avocado (including the ones likely taught in your local knife skills class, or simply using a spoon), but there’s also another option. You could just buy one that doesn’t have a pit at all, as The Telegraph reports.

British retailer Marks & Spencer has started selling cocktail avocados, a skinny, almost zucchini-like type of avocado that doesn’t have a seed inside. Grown in Spain, they’re hard to find in stores (Marks & Spencer seems to be the only place in the UK to have them), and are only available during the month of December.

The avocados aren’t genetically modified, according to The Independent. They grow naturally from an unpollinated avocado blossom, and their growth is stunted by the lack of seed. Though you may not be able to find them in your local grocery, these “avocaditos” can grow wherever regular-sized Fuerte avocados grow, including Mexico and California, and some specialty producers already sell them in the U.S. Despite the elongated shape, they taste pretty much like any other avocado. But you don’t really need a knife to eat them, since the skin is edible, too.

If you insist on taking your life in your hand and pitting your own full-sized avocado, click here to let us guide you through the process. No one wants to go to the ER over a salad topping, no matter how delicious. Safety first!

[h/t The Telegraph]

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