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Brain Academy -Exploring Some Popular Myths about the Brain

Wednesday, 31 March 2010

Prof. Aidan Moran

What's the danger of popular myths?

They impede scientific understanding and can be harmful/costly (e.g., investing in expensive products that "boost our brain-power" is usually a waste of time - there are plenty of inexpensive ways of increasing one's cognitive skills)

How do they arise?

Exaggeration of a grain of truth .Word of mouth. we all have a desire/hope for a quick fix . selective perception (we see what we want to see)

Why are they so tenacious/resistant to change?

Because critical thinking/weighing up the evidence is hard work . Bertrand Russell (philosopher) once said that "Most people would sooner die than think, and in fact they do"!

5 Myths about the Brain:-

Myth 1:- "We only use 10% of our brains"

Myth 2:- "Are we in our right minds? Some people are left-brained (verbal, rational, scientific) whereas others are right-brained (intuitive, emotional, artistic)"

Myth 3:- "Memory is like a box in which we store things and works like a tape recorder or video camera"

Myth 4:- "People's memories decline dramatically with age" (only partly true - children forget as many things as adults but they don't worry about it!. Although some types of memory decline with age, other don't)

Myth 5:- "There is no limit to our multi-tasking skills" - this claim is exaggerated: there are definite limits on the types of jobs that what we can and cannot do at the same time"

Exercise:- While sitting down, lift your right foot off the floor and make clockwise circles with it. Then, while doing this draw the number "6" in the air with tour right hand. Notice that your foot will suddenly change direction - and there's nothing you can do about it"!

Myth 1:- "We use only 10% of our brains" (would you be ok if we removed 90% of your brain?!!)

Good overview of the myth: See http://faculty.washington.edu/chudler/tenper.html

Origin of the Myth:-

Two sources:

1. Probably began with a misquote from the famous American psychologist William James (who had Irish ancestry) who claimed that the average person uses only about 10% of his or her potential - not brain: "We are making use of only a small part of our possible mental and physical resources" (from The Energies of Men, 1908, p. 12).

Also appears in the preface to Dale Carnegie's (1936) book "How to win friends and influence people'. Also attributed to Albert Einstein - but never actually said by him. This "10% myth" also influenced by a misunderstanding of early neuroscience research findings: Early brain researchers said that they couldn't "map" the precise function of 90% of brain - but that's not the same as saying that 90% of brain does NOTHING!

Evidence against the Myth:-

. Modern brain imaging techniques have helped to identify specific psychological functions that are performed by specific areas of the brain (e.g., occipital lobe and vision/visual imagery) - there are very few, if any, "quiet" areas (let alone 90% "quiet areas").

. The brain has evolved though natural selection - why would it have adapted so that 90% of it is 'silent'?

What we know now: It's not literally true but there is a grain of truth to it. As we have LOTS of potential room for improvement mentally - e.g., our long term memory system has no known capacity limit. Also, we can improve the efficiency of our brain's activities by strategic or "deliberate" practice.
Myth 2:-"Are we in our right minds? Is it true that some people are left-brained (logical, verbal, rational, scientific) whereas others are right-brained (intuitive, emotional, artistic)?"

Origin of the Myth:-

There is evidence from research by Roger Sperry (who won the Nobel prize for his 'split brain' studies in the 1960s) that the two sides of the brain (called "hemispheres") differ in their functions. The right hemisphere controls the movement of the left side of the body and spatial perception and the left hemisphere controls the right side of the body.

In general, the hemispheres are specialized for different skills. For example, language and logic and thinking are predominantly located in the left side of our brains - BUT this specialization does not mean that the right hemisphere has no language powers at all.

The Facts:-

The brain works in a very integrated manner. Need both working parallel to do virtually every function. So, the idea that people are EITHER left-brained OR right-brained is simply not true. Can be more-right brained or left brained but not either left or right brained.

And you can improve each area. As long as the bridge ("corpus callosum") between the hemispheres is intact, the two hemispheres share information extensively. Modern psychology research shows that the two hemispheres are more similar than different in their functions.

Myth 3:- "Memory is like a box in which we store things and works like a tape recorder or video camera."

In 2000: Eleanor Maguire study of London Taxi drivers and their brains (hippocampus) expanded as a result of the memorizing of the geographical layout of the city. Practice can also expand the mind. Memory is a living thing and the more you feed it the more it will expand. http://news.bbc.co.uk/2/hi/677048.stm

Origin of the Myth:-

Many people believe that their memories operate like boxes, tape recorders, video cameras or DVDs - storing and replaying events exactly as they happened. Brains are not. They are more like a computer but our brain can also store more things like smells, sounds. An infant's brain is far more sophisticated than a computer.

Facts:-

Many people look upon memory as a container like a filing system. Unfortunately, this analogy breaks down when we discover that, unlike a container, our memory system never fills up completely. In fact, it actually expands to accommodate new knowledge.
The more you know about a field, the more you will be able to remember in that area.

How about regarding memory as a video-recorder? Unfortunately, this analogy is also false because research shows that what our minds "play back" is not necessarily the same.

As what went in originally. In other words, our minds register what we think happened - not what actually occurred. This finding means that we store interpretations of events - not the events themselves.

So, remembering is a constructive process as we fill in the gaps in our memories with our knowledge and expectations. Therefore, many of our cherished memories of events are mixtures of what actually happened and what we imagine should have happened.

Finally, our memory is not like a computer for several reasons. For example, we search our "knowledge base" differently from the way in which computers retrieve memories.

For example, if a computer were asked "What is Shakespeare's telephone number?" it would search its memory files for entries under "saints" and "telephone numbers". But when faced with the same question, people would use their reasoning processes to decide not waste any time in consulting their memories.

And that brings us to a critical difference between our minds and computers: We tend to get faster as doing things as we acquire more knowledge whereas computers slow down with increases in the size of their knowledge base.

Our memories are mixtures of fact and interpretation/imagination.
Memory is inseparable from thinking: What we recall is influenced greatly by what we already believe or know: Much of what we remember is constructed from prior knowledge or from our imagination, rather than from what we actually experienced
e.g., can be illustrated by simple story:

"Mary heard an ice-cream van coming down the road. She ran inside to get her money"


Why is this story so important to memory researchers? What does it tell us about how the mind works? Most people assume that Mary is a little girl (not stated) and that because children like ice-cream (not stated), that she is going inside to get money to buy ice-cream . notice all the assumptions/implications that are added and subsequently "remembered" by the person hearing his story .

Myth 4:-"People's memories decline dramatically with age" (only partly true - children forget as many things as adults but they don't worry about it! Although some types of memory decline with age, others don't)

Although some types of memory decline with age (e.g., formation of new memories), other types of memory don't (e.g., "procedural" memory - memories for skills & early experiences). Our understanding of the meaning of words doesn't decline.

Also, research shows that children forget almost as much as older people but the difference is that they don't worry about it!

Fact: Our memory system is remarkably good - most of the time!

We tend to notice our memory system only when it lets us down in some way (e.g., we fail to recall someone's name although we know that we know it)- but it actually gets through an enormous amount of hidden work in any given day.

Maintaining our sense of identity - who we are - "autobiographical memory" - early experiences - look at a photo and remember being there. "Flashbulb memory" - where you were when you heard of the death of Diana, Twin Towers, assassination of JFK for example, who you were with, what you were doing.

Recalling facts and rules such as word meanings/basic maths (e.g., 2+2=4) - "semantic memory."

Remembering everyday actions/skills (e.g., how to make a cup of tea; how to ride a bicycle) - "procedural memory."

Helping us to "see" movement in television/cinema - there is a time-lag between what is shown to us on screen (a series of still images) and what our brain interprets (movement between these stills). Can be illustrated by the "RUBBERY PENCIL" effect - hold a pencil between two of your fingers at arm's length and shake it gently so that it appears to be flexible/rubbery .our mind's ability is slightly time lagged, slightly behind reality.


Myth 5:- "There is no limit to our multi-tasking skills" - this claim is exaggerated: there are definite limits on the types of jobs that what we can and cannot do at the same time" Though self help books might tell you differently.

Exercise:-

While sitting down, lift your right foot off the floor and make clockwise circles with it. Then, while doing this draw the number "6" in the air with tour right hand. Notice that your foot will suddenly change direction - and there's nothing you can do about it"!

We can do pairs of tasks if they use different sensory systems (e.g., reading the paper and listening to music) but we find it very difficult to do two tasks at the same time if they occupy the same sensory system - see From my book "Sport and Exercise Psychology" (2004, p. 143): Example of difficulty of listening to football match on car radio while driving!

Why you should not listen to football commentaries while driving: interference between imagery and action.

It has long been known that people have great difficulty in perceiving and imagining information presented in the same sensory modality. For example, try to form a mental image of your friend's face while reading this page.

If you are like most people, you should find this task rather difficult because the cognitive activities of forming a visual image and reading text on a page draw upon the same neural pathways. Another example of this "like-modality" interference problem occurs if you try to imagine your favourite song in your "mind's ear" while listening to music on the radio.

Just as before, auditory perception and auditory imagery interfere with each other because both tasks compete for the same processing pathways on the brain.

An interesting practical implication of this interference phenomenon is that you should not listen to football matches while driving your car because both tasks require visual processing. This time, unfortunately, cognitive interference could result in a nasty accident!

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