Snack Judgment


We are told from our mother’s knee, and the health websites that we are increasingly taking as our source of wisdom, that we should start the day right with a good breakfast and then eat small regular meals throughout the day. Browsing on the odd snack with a blowout in the late evening is the way to perdition.

Well, it turns out that if we take the unhealthy route, the road to perdition might be the correct description, but not necessarily for us if we are the judge, but likely for those being judged. Danziger et al studied the parole decisions handed down by 8 judges as a function of the time of day (1,2).

The judge’s days were hard with about 28 cases to make judgments on. They also had a few which the prosecutor and the defense attorney already agreed on and these were taken out of the analysis. The judges had a snack break mid-morning and then a lunch break, so their judging day was split into three sessions.

The results of the study were startling. If your application for parole came up at the start of a session, you would have a 60 to 65% chance of being granted parole. But if the snack time was nigh, your chances were down to less than 20% and with some judges, close to 0%.

But that’s not all. Letting people out of jail is hard work – a big responsibility, and a judge, like the rest of us, gets tired during a hard days work so your chances of going home decrease as the day progresses notwithstanding that just after a good lunch your chance is a little better than 50/50. By the end of the day, things look very bleak.

We are left to speculate how the trend goes with the day of the week. Would Wednesday be a bad choice as it looks like there’s still a long way to the weekend and is there a TGIF bit of frivolity in the court-room? Or does dressing down Friday mean something else?

  1. S. Danziger, J. Levav and L. Avnaim-Pesso, PNAS, 108, 6889, (2011)
  2. AIR, 17, 23, (2011).

Model Trees


How big is a tree, is a similar question to how long is a piece of string? But how big should it be seems to be just as intangible. Species is the first thing that comes to mind, although the quality of the soil, the rainfall, sunlight and temperature come fast behind.

A great deal of effort has already been expended on computer modeling of the growth of trees and the density of forests. Most of this is either very expensive in computer time or too specific. Either way, there is always room for one more computer model to add to the debate.

The new one is by Kempes et al and makes use a standard mathematical tree – a fractal design with a series of scaling rules for local meteorology and the flow of water through the structure (1). The more favorable the energy budget, the bigger the dendritic superstructure of the tree, and hence, the taller it grows.

Of course, a pre-requisite is good local information. Species can be allowed for if average heights are scaled in. The model is remarkably successful at predicting the maximum heights across the various regions of the US.

If the local meteorology is changed, to account for some trait such as global warming, a concomitant variation in tree size is seen. An added bit of information is the density of the cells controlling the water flow in the canopy along with the density of the canopy.

 This in turn can be used to calculate the reflectivity of the canopy, carbon sequestration and all sorts of scary information that most of us will ignore and then look surprised. Rather like the changes in the local climate in southern Somalia due to the decimation of the acacia forest to satisfy the charcoal export trade. Some joined up thinking about all our futures is long overdue.

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0020551

Ouch!


Empathy for our fellow person's condition is something that we should all cultivate, but how far down the road will we travel? Not many as far as Sidney carton in “Tale Of Two Cities” as he heads off to the guillotine (sorry, but some puns are just irresistible) with the phrase “it’s a far, far better thing that I do now …..” and leaves Darnay free to lose his head over his wife, Lucie.

Us lesser mortals can do our bit though, given the opportunity. Grit et al used increases in skin conductance as a measure of empathy when a group of young women saw each other getting electric shocks (1). Young women were chosen so as not to bring the complicating factor of gender into the discussion. It seems that they may only have half the story, but perhaps they’ll extend the work to young men and get some shocking results.

The participants were each subjected to electric shocks ranging in pain levels from very mild to ouch!! The magnitude was displayed on a computer screen as a visual to any observer. The skin conductance of observers was measured to give an empathy strength reading. The more severe things looked, the sweatier the observers became

So far, so good. Nothing surprising, but this was just the baseline. The interesting experiment came when the observers could do a Sidney Carton, and offer to take the shock themselves and relieve the burden on the subject.

Two interesting finding turned up. The first is that those who showed more empathy were more likely to step up and volunteer to “take one for the team.” When shocked, the participants skin conductance increased, but the smaller the difference between the skin conductance between them being shocked and watching someone else suffering was a good predictor of their volunteering do a Carton.

These guys really need to do the same experiment with men and then with people from an older age group. Do empathic tendencies increase with age?

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022759

Moaning Moose


Female moose from Alaska go for the big guy. The bigger and tougher the better in that wild part of the world and, in turn, the big guy keeps his girls together and defends them from other ‘big guys’.  Of course, thing aren’t all that simple as he has to take time out to eat and dream like guys everywhere. Other moose will come calling and hang around in a purely conversational way, but will then take liberties if he is off tending to important matters elsewhere.

As we all know, it takes two to tango. The females in the harem can get very sniffy about whose going to be the father of their youngsters. Many other species have females who are much more willing than moose to have the odd fling and keep the gene pool wide.

With the Alaskan moose, Bowyer et al have picked up on their behavior and reported on it in the current issue of Behavioral Ecology and Sociobiology. The found that if another male comes courting them, the females moan loudly in protest. The effect of a moaning female is that the males start to fight, egged on by the moaning protests at the liberty that was suggested.

If the females stop moaning, the guys settled down and there was much less fighting going on. Hence, a lot of moaning got the guys on edge and started fights, but the females moaned a lot more if the lothario was a small guy than if he was a big guy. The bigger he was the less moaning went on about the whole tedious business. I guess they were less offended and would possible wander off with him, if he were big enough. There would be no protesting and moaning about headaches then.

  1.  http://www.springerlink.com/content/0340-5443

Wise Sheep


Plants have quite a struggle to get the best spots with plenty of light and water to put down roots and get established in the good life. As if that weren’t enough, many members of the animal kingdom are addicted to herbivory and will suck the sap or chew the leaves. A defensive mechanism of the plants is to produce tannins. These polyphenols are a good insect deterrent but are not so effective against vertebrate munchers.

The arms race is on and mammalian herbivores, as well as some marsupials, produce some proline rich salivary proteins that bind to the polyphenols and take them out of the picture – up to a point, that is. Being stuck with a diet that is high in tannins is not a pleasant option.

So what is a sheep to do if she is stuck in a pen with a high tannin diet? She’ll rely on chemistry and self-medicate with high molecular weight polyethylene glycol, PEG, as available in over the counter laxatives. That of course means that she will have to raid her shepherd’s bathroom cabinet. Sanga et al of Utah State U have reported on a study of this behavior (1). The big question they wanted answered was what did they tell their offspring?

Two groups of ewes were picked and one group was fed tannin-rich feed and the other was on normal rations. The tannin-rich group quickly learned to self medicate and now the scene was set. The alternative to PEG was a placebo in the form of grape pomace. When both groups were subsequently stuck on the high-tannin feed and offered PEG or pomace, the wise old gals munched away heartily and choose PEG dessert. Not so with the naïve ones they didn’t eat much were a bit slow on the laxatives.

After their lambs were weaned, the ones with wise moms had no trouble and got stuck into PEG dessert and even the ones with the relatively naïve moms tried that route too. A group of young lambs on their own had trouble as no one had told them to eat their PEG.

I guess it is a reminder to us all to talk to our kids about the junk food their eating and to keep our bathroom cabinets stocked up.

  1. U.Sanga, F.D.Provenza & J.J.Villalba, Animal Behavior, 82, 219, (2011).

Robot Softies


Robots currently fall into three categories. The most widely used are no-nonsense machines that we use but don’t feel very much affection for. A second category is the cuddly therapeutic machines that respond to touch and sound but don’t really do anything expect make us feel better. The third category is those cute-looking little humanoid machines that do things like play world-cup soccer. None of these quite cut it, though, when it comes to machines that we would really like to interact with.

What we need are machines which can do things for us, but which feel and look organic. This brings us into the current research area of soft robotics, which is covered by the journal Bioinspiration and Biomimetics.

Calisti et al, have made a start on building a robotic octopus (1). At the current state it is a monopus with only one tentacle, but that tentacle can wave around, grip an object or make a good start at crawling. The tentacle is made of a silicone elastomer. It doesn’t have suckers, but doesn’t suck at gripping so don't get too close.

Running about is a good way to get over rough ground, which is why so many animals like us have legs. Running is a complex process and requires a sophisticated control strategy. Andrews et al have built a one legged planar robot that can change it’s leg length as a sinusoidal function of time (2). So it can stand, or hop like mad with different frequencies. Once it gets it’s other leg, it will be able to step over obstacles. Jumping hurdles may take a little longer.

The last bit of bioinspiration that I want to draw to your attention to, is the build of micro air vehicles by Shang et al (3) that have flapping wings. We have met these before in an earlier blog in connection with the experimental humming bird spybots built for the guys in dark grey suits and sunglasses. What is new here, though, is that the wings are modeled on those of insects and the progressive flexibility that is needed to simulate insect wing shape when flapped, is built in with the vein structure.

Can you picture the world tomorrow where we could have robot mosquitos about a centimeter in length chasing fast running robots who, if they jump into water to avoid the robomozzies, will get grabbed and consumed by an octibot? Will we see robot chimera? Say a robomozzie with tentacles?

  1. http://iopscience.iop.org/1748-3190/6/3/036002
  2. http://iopscience.iop.org/1748-3190/6/2/026009
  3. http://iopscience.iop.org/1748-3190/6/3/036002