False Memories Are Made Of This.


Memories are sometimes good and sometimes bad, but they may not be accurate. Sometimes we compress things and even remember the wrong person being present. Worst of all, we can feel convinced we did something which it turns out we didn’t actually do.

We can believe strongly in these false memories, but what happens when we find out that some of those fond memories (or bad ones) didn’t actually occur? Do we abandon them entirely so they are forgotten, or have those pesky neurons got those robust connections so the pictures still play across the screen in our head even though we know it didn’t happen?

It turns out that we don’t have to believe something happened to picture it happening to us. This week Clark et al report on their experiments to create false memories in 20 of their unsuspecting students (1). The memories weren’t of anything memorable. They had the students copy the experimenter doing simple actions such as clapping their hands, rubbing the table with the palms of their hands or covering their faces. All the while they were video taped.

After one session they introduced some fake shots of the experimenter doing things that they hadn’t done in the monkey see – monkey do session. After giving them some anagrams to solve to help put their memories into the closet, they were shown the tapes of the experimenter and had to say which they had seen and copied.

After a four-hour break, the experimenters ’fessed up and then got the students to rate their memories of performing the actions. So, what were the results? Firstly, the false memories were easily and effectively planted. Secondly, even after they were told about the fakes and they didn’t believe that they had completed those particular actions, they still had memories of doing them.

This result has some really scary implications as it seems that we can easily be fooled into remembering we done something when we have not done it and don’t even believe we have, but that worrying little picture is playing among our brain cells.

I guess it is even more important than ever to remind our politicians about what they actually did to help demolish their false memories of doing a splendid job for us all.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032998


Trading Up


More and more of us follow the gyrations of the stock market on a regular basis, usually with hope rather than conviction that we know what to expect from it. Now, it has long been a business axiom that hope is not a strategy for success, but nevertheless we harbor it as we think what to do about any savings that we have still managed to cling to.

Trading is a practice, which we indulge in early in our lifetimes and we sometimes learned to be fair and to trust our trading partners, those of us who didn’t, either came to a bad end or became super rich or politicians. At what age do we learn to be canny but honest (of course) traders?

The answer to that telling question is at hand. Steelandt and her colleagues from U de Strasbourg have published their research on trading youngsters in this week’s PloSONE (1). They played a trading game with 3-year olds, 5-year olds, 7-year olds and 10-year olds. They didn’t play for money, of course, but the played for small candies.

Each child was introduced to two trading partners sequentially. One partner offered a return of double the number of candies invested, while the other offered a fixed return regardless of how much was invested. In addition the youngsters had the choice of eating into their assets. Sixteen little girls and sixteen little boys don’t make a large trading floor, but it’s a start.

To maximize one’s profits the trading strategy with one partner was to maximize the investment to get double, but with the other partner the minimum investment got the same pay out so profits were maximized by minimum outlay. The 7 and 10-year olds were all able to grasp that concept, although they sometimes didn’t follow the logic and gave a justification for a bad-trading decision.

About a third of the 5-year olds managed to do well as successful traders but none of the 3-year olds managed to optimize their returns by adjusting their offers. They seemed to trust the trading floor to treat them generously and took what they were handed down without question.

Similar experiments with non-human primates, namely capuchins and macaques resulted in similar performance traits to the 3-year old humans. Having read some investment proposals over the past years, I wonder if some of the financial wunderkinder think we are either all 3-year olds or monkeys.


  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0033239


Ant Navigators


The ant with the rather impressive name Cataglyphis lives in the Sahara desert and lives on insects that have died from heat exhaustion. They can cope with temperatures up to 50 °C and have their nest in the ground which they enter through a small hole.

So when an ant goes walkabout in the search for food it has to know how far it has gone and in what direction; quite a challenge for a small creature. They use the polarization of sunlight to give them a direction and (apparently) count steps to estimate how far they have walked. Like dead reckoning, this navigational practice is not always accurate.

So what else do they have in their armory? Buehlmann et al from the Jena Max Planck have give us the answer. They set up an ant training establishment were the ants learned to find food in a feeding trough. They then transferred the ants into a parallel trough with a series of landmarks to help them get oriented.

The landmarks were i. a black signpost, ii. A drop of a methyl salycilate solution to give a nice olefactory experience, iii. a vibrating rod and finally iv. an electromagnet. In each case they watched as the ants try and find their way home.

Those ants who had worked with dead reckoning got confused and still tried to use that to get home although they had been displaced without their consent. Those that had been trained with the landmarks at their nest entrance, in each case homed in on the landmark in favor of the dead reckoning.

It is worthwhile noting that none of the landmarks where attractive to the ants. They needed several runs to understand that the landmark was in fact an indictor of their nest entrance location. First timers missed the point.

So it seems that ants are very capable little navigators, which are versatile in using different senses for navigational aids, as well as be good at dead reckoning. It makes those of us who are reliant on their GPS systems to find our cars in large car parks out to be somewhat navigationally challenged.


  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0033117


Speaking At The Preferred Frequency


Once again the pitch of peoples voices is the subject of a research project. This time the pitch has been progressively manipulated over a wide range to see how people respond. Previous work has already established how the pitch of a voice is perceived in terms of authority – a lower pitch carries more weight than a higher pitch, but what do we find attractive?

Re at al from McMaster U have decided to let us in on their results from a study with 10 male and 9 female students (1). The students listened to the pronunciation of simple vowels sounds that were electronically manipulated over 2 Hz steps from very low pitches to very high pitches. The full human range was investigated.

But what question was asked? What did their 19 human lab rats prefer for male and female voices. Note: the men weren’t asked to rate the men’s voices and the women didn’t have to worry about the women’s voices. The choice was the preferred pitch of the opposite sex.

The results? The men preferred women’s voices at the high end of the pitch range. Now, for the women the preferred frequency for men’s voices was a low frequency, but not too low, certainly not at the extreme.

I’m left wondering what this means. Does an extremely low male voice sound too authoritative for a rebellious student? Maybe. And why would the guys prefer an extremely high-pitched women’s voice? What’s happened to the attraction of the husky woman’s voice whispering in the ear? Are the winters in Ontario to cold to think of such things? I doubt it. There must be some other explanation at work for such an odd result.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032719


They Saw A Sawfish's Saw At Work


The freshwater sawfish is a highly endangered species of fish that is trying to make a living in rivers and estuaries, but many have been sent to aquarium prisons and others are finding their habitat disappearing. They are related to sharks and rays and like them and sturgeons they are sensitive to electric fields produced by fish.

 The head of a sawfish has an elongated length of cartilage, which has teeth sticking out along the length. A new study of these creatures has just been published in Current Biology by Wueringer et al which describes how they use their saw (1, 2).

The saw has electric field detectors along its length which helps the fish find its lunch, which may consist of catfish, mullet or freshwater prawns. But just as many things in nature are dual or more purpose, so is the saw.

When a nice juicy catfish is detected, a vicious sideways swipe impales the prey fish and the sawfish then manipulates the fish to a head on position for gulping down. Eating catfish whole this way is a must as it has poisonous spines pointing backwards along its dorsal surface.

So nature has provided the sawfish with combined lunch detector and weapon, which is ever ready for action. It is readily sharpened by honing it on the bottom of the river. The big downside is that nobody has taught it about fishing nets. A fishing net full of wriggling fish can be too tempting and a quick slash at the captured fish can end with the sawfish’s saw entangled.

  1. http://www.cell.com/current-biology/fulltext/S0960-9822(12)00085-1
  2. http://www.bbc.co.uk/news/science-environment-17258808


From Draglines For Timbre To Spider Ranching


Spiders put a great deal of effort into spinning silk, building webs and the keeping them in good repair. Not all their threads are the same though. The thickest and strongest is their dragline silk. Over the centuries we have looked at the silk and tried to make use of it.

Wound dressing is one application that was tried many years ago with some success and it has been used as cross hairs in some scientific equipment, but not many other practical uses have been devised. The main reason is the collection of large enough quantities that would be required for commercial exploitation.

However, a new high-end use has been tried out by Osaki at Nara Med. U (1, 2). Dr. Osaki has been ranching a brand of golden orb-weaver spiders in his lab in Japan. With three hundred of these working hard, he has collected dragline silk to twist into fibers.

Up to 5,000 strands were twisted together first and then three of these fibers were twisted together in the opposite direction. The resulting fibers were used to string Dr. Osaki’s violin. They are strong and elastic; stronger than gut but not as strong as nylon strings.

The twisting process binds them so tightly together that the fibers deform to make intimate contact with their neighbors and leaving no gaps inside the bundle.

The elasticity of the strings is such that the overtones of the notes played are more pronounced than those produced with conventional stringing. This is most marked with the higher notes. The net result in psychoacoustic terms is an enhanced timbre or tonal quality – one of those difficult things to describe but one knows it when one hears it.

Perhaps we will soon hear a Stradivarius strung with dragline silk for the ultimate musical experience.


  1. http://prl.aps.org/accepted/L/25078Ye0Yef1163de18a8722105e7914a797506ee
  2. http://www.bbc.co.uk/news/science-environment-17232058