the alpha and omega : topic:NatScience

Birds plan for future desires

Mahalanobis — 2007-04-29T16:01:00Z

The Economist: HOARDING provisions for future use is not unique to humans. Birds, squirrels and monkeys do it. But the ability to think not just about tomorrow, but to realise how tomorrow's feelings might differ from today's, was thought to be the preserve of people (Bischof-Köhler hypothesis). This week researchers demonstrated that Western scrub-jays, a type of crow, can do it too. <>

To test whether this is so, Nicola Clayton et al. sought to tease apart scrub-jays' momentary desires from their planning for future needs. They let the birds eat as much of one food as they wanted, exploiting a condition called specific satietyonce the birds are full of one food, they show strong preference for something different. They then offered the birds that same food or a second one to store for later.

Initially the scrub-jays behaved as predicted, choosing to stow away the second food, which they had not just eaten. But minutes before allowing the birds to recover their stash, the researchers fed the birds to satiety with that second foodthe one they had already stored. The birds changed their caching preferences on the very next trial. Even though they had just had their fill of the first food, they still cached it, presumably because they thought it would be their preferred choice later. The results are published in this week's Current Biology

The finding matters because the birds seem to plan ahead for what they will want later, even though their choice conflicts with what they want now. [Source]

Kolmogorov scaling in impassioned van Gogh paintings

Mahalanobis — 2006-07-09T10:26:00Z

Nature: Vincent van Gogh is known for his chaotic paintings and similarly tumultuous state of mind. Now a mathematical analysis of his works reveals that the stormy patterns in many of his paintings [The Starry Night (1889), Road with Cypress and Star (1890), and Wheat Field with Crows (1890)] are uncannily like real turbulence, as seen in swirling water or the air from a jet engine.

"We think that van Gogh had a unique ability to depict turbulence in periods of prolonged psychotic agitation," says physicist Jose Luis Aragon. Click here (mirror) to read the whole story.

Pigeon-brained birds can think in logarithms

Mahalanobis — 2006-05-21T21:37:00Z

New Scientist: CONFUSED by logarithms? If so, you'll be surprised to hear they come naturally to pigeons and possibly, subconsciously, to you.

There are asymmetries in the way animals perceive numbers and time, and a recent experiment showed that pigeons underestimate the midpoint between two time intervals.

In the experiment, pigeons were trained to tap one lever when a light flash was "short", perhaps 1 second long, and another lever when the flash was "long", say 16 seconds. When the birds then saw flashes of intermediate length, you would expect them to distinguish long from short around the mid-point of 8 or 9 seconds. But instead they switched at 4 seconds.

Pigeons might perceive time on a logarithmic scale on which higher values are increasingly compressed together. Alternatively, they might perceive time linearly but are confused by longer intervals. If pigeons use a log scale, they will correctly classify 9 and 10-second flashes more often than 7 and 8-second flashes, while if they use a linear model their accuracy should be similar. William Roberts from the University of Western Ontario in London, Canada, has now shown that six pigeons, tapping levers for 20 days, conformed neatly to the logarithmic model (Behavioural Processes, vol 72, p 207).

The results may apply to humans, because brains have to prioritise the small numbers most relevant in life. It might be an evolutionary strategy to discriminate numbers like this, says Roberts. [Source]

In the beginning...

Mahalanobis — 2006-02-19T03:22:26Z

How life on Earth got going is still mysterious, but not for want of ideas

Quicksand can't suck you under

Mahalanobis — 2005-09-29T19:33:26Z

Nature: Although horror films frequently depict victims disappearing in quicksand, the truth is much tamer. People cannot fully sink into this type of soil, and laboratory simulations now bear out this little-known fact.

Click here to read the whole story.

A cosmic hall of mirrors

Mahalanobis — 2005-09-05T20:47:19Z

IOP: People have long been fascinated by the size and shape of the universe. The current consensus among astronomers is that the universe is flat - which means that parallel lines never meet - and that it is infinite in size. Some of the strongest evidence for this view comes from measurements of the cosmic background radiation - a fuzz of microwaves known as the echo of the big bang - made by NASA's WMAP satellite. However, when the results from WMAP are compared with theory at large angles, there is a discrepancy that suggests that the universe might not be flat or infinite after all. Indeed, as Jean-Pierre Luminet of the Observatory of Paris explains, the data might be better explained by a universe that is shaped a bit like a ~~football~~ soccer ball - a Poincaré dodecahedron to be precise. Moreover, the universe resembles a video game in that if you disappear out through one of the "panels" that make up the football, you immediately re-appear through another panel on the opposite side.

The Most Influential Individuals are Generally Bad

HedgeFundGuy — 2005-08-30T19:14:05Z

Arnold Kling asks (see here) who is the most influential person in world history, and suggests names like Locke, Smith, and Marx.

In my opinion this general question is biased towards the knuckleheads like Marx who were fabulously influential and wrong. This is because influential mistakes create something neither anticipated nor inevitable, while right ideas are somewhat inevitable. Thus good ideas are not so dependent on "great men" because there are lots of smart people and they eventually find the truth (witness the simultaneous discovery of things like evolution by Wallace and Darwin, calculus by Newton and Leibniz, or marginal analysis in economics by Menger, Jevons, and Walras). Bad ideas, in contrast, are infinite in number, and require a special magnetism and impenetrable self-assurance by their champions in order to become influential. Freud is a perfect example, a charlatan who befuddled two generations via his implacable self-esteem. Marx was similar, and Ayn Rand was cut from the same cloth but fortunately her radical ideas against empiricism never had as deleteriously wide an impact as Marx or Freud.

So for an individual to have great impact, it is probably in some wrong-headed idea about something not obviously falsifiable.

Quiz :: The Power of Tiny Things

Mahalanobis — 2005-08-04T03:27:40Z

Have you ever thought about the power of a paper clip? If you could convert the mass of a paper clip entirely to energy, how big a punch would it pack? In this quiz, discover the answer and explore other examples of what scientists call mass-energy equivalence.

E = mc² Explained: Hear how 10 top physiciststwo Nobel Prize winners among themdescribe the equation in a few minutes or less. Click here to listen directly to Einstein.

Get the learning habit

Mahalanobis — 2005-07-30T22:58:38Z

Nature: Habit memory is acquired subconsciously and slowly, by trial-and-error. It is more easily studied in animals than in humans, because of our strong tendency to acquire information as conscious (declarative) knowledge. Yet our capacity for unconscious learning is a vital aspect of the human condition, facilitating many routine tasks. Now it can be confirmed that humans do have a robust capacity for habit learning. Two patients with large medial temporal lobe lesions and profound amnesia were asked to acquire a task that is ordinarily learned by conscious memory. They learned gradually, in the way that monkeys learn the same task, and without being aware of what was being learned. The knowledge was rigidly organized, and performance collapsed when the task format was altered. Click here to read the story.

Fingernails store personal information

Mahalanobis — 2005-07-21T15:36:14Z

PhysicsWeb: Secure optical data storage could soon literally be at your fingertips thanks to work being carried out in Japan. Yoshio Hayasaki of Tokushima University and colleagues have discovered that data can be written into a human fingernail by irradiating it with femtosecond laser pulses. Capacities are said to be up to 5 mega bits [655 360 bytes] and the stored data lasts for 6 months -- the length of time it takes a fingernail to be completely replaced (Optics Express 13 4560). Continue Reading

via jupe

125 Questions: What don't we know?

Mahalanobis — 2005-07-02T02:23:46Z

In a special collection of articles published beginning today, Science Magazine and its online companion sites celebrate the journal's 125th anniversary with a look forward at the most compelling puzzles and questions facing scientists today.

via The Presurfer

No paradox for time travellers

Mahalanobis — 2005-06-19T15:25:13Z

New Scientist: THE laws of physics seem to permit time travel, and with it, paradoxical situations such as the possibility that people could go back in time to prevent their own birth. But it turns out that such paradoxes may be ruled out by the weirdness inherent in laws of quantum physics.

Some solutions to the equations of Einstein's general theory of relativity lead to situations in which space-time curves back on itself, theoretically allowing travellers to loop back in time and meet younger versions of themselves. Because such time travel sets up paradoxes, many researchers suspect that some physical constraints must make time travel impossible. Now, physicists Daniel Greenberger of the City University of New York and Karl Svozil of the Vienna University of Technology in Austria have shown that the most basic features of quantum theory may ensure that time travellers could never alter the past, even if they are able to go back in time. Click here to read the story.

Watching New Love as It Sears the Brain

Mahalanobis — 2005-06-03T23:02:56Z

The Age: When it strikes, romantic love can feel like a kind of madness. Infatuated people act irrationally. They lose concentration. They feel giddy, wretched and wonderful. It is one of life's most powerful experiences. Emily Dickinson described it as "a perfect - paralysing bliss - contented as despair".
For centuries, we've looked to philosophers and poets to parse the mysteries of the human heart. Now it is science's turn. [login and pwd: dailykos]

via Abiola Lapite ("One thing this does illustrate is the wisdom of the advice of being the first to dump the other in a romantic relationship one senses is bound for the rocks, even if one would prefer that the relationship continue." - Yeah, tit for tat isn't always the optimal strategy...)

related items:
Reward, Motivation and Emotion Systems Associated with
Early-Stage Intense Romantic Love

Man liebt zuletzt seine Begierde, und nicht das Begehrte. -- Friedrich Nietzsche

Scientists Discover Trust Potion

Mahalanobis — 2005-06-01T19:13:06Z

LiveScience: <> Scientists discovered that inhaling the chemical made people more trusting in social situations with random people.

Researchers know very little about the biological basis of trust. Michael Kosfeld and his colleagues at the University of Zurich believed oxytocin a chemical widely known to enhance social bonding in animals and currently used to induce labor and lactation in human mothers might play a role.

So Kosfeld and his colleagues set up a game involving two people one playing the role of an anonymous trustee who asked an investor for money for a risky scheme. Investors who sniffed oxytocin trusted the trustee significantly more and handed over their money much more readily, the scientists found. To determine whether this result was truly trust oriented, the researchers did a control experiment that replaced the trustee with a computer. Investors even those given oxytocin were not as likely to risk their money to the automaton. Researchers say this result shows oxytocin enhances trust between individuals rather than just making people less averse to risks.

This study will be detailed in the June 2 issue of the journal Nature.

"The finding opens up possibilities for investigating conditions in which trust is either diminished, as in autism, or augmented," said Antonio Damasio, a University of Iowa researcher who was not involved in the research. |Source|

related items:
A Bayesian Truth Serum for Subjective Data, Mahalanobis

His Brain, Her Brain

Mahalanobis — 2005-05-16T23:38:29Z

Scientific American: [O]ver the past decade investigators have documented an astonishing array of structural, chemical and functional variations in the brains of males and females. These inequities are not just interesting idiosyncrasies that might explain why more men than women enjoy the Three Stooges. They raise the possibility that we might need to develop sex-specific treatments for a host of conditions, including depression, addiction, schizophrenia and post-traumatic stress disorder (PTSD). Furthermore, the differences imply that researchers exploring the structure and function of the brain must take into account the sex of their subjects when analyzing their data--and include both women and men in future studies or risk obtaining misleading results. Click here to read the whole story.

addendum :: related items:
This Is Your Brain, On Sex :: Let's Fly Under the Bridge