Aesop’s Fable Unlocks How Crows and Kids Think

ScienceDaily (July 25, 2012) — Cambridge scientists have used an age-old fable to help illustrate how we think differently to other animals.


 

Lucy Cheke, a PhD student at the University of Cambridge’s Department of Experimental Psychology, expanded Aesop’s fable into three tasks of varying complexity and compared the performance of Eurasian Jays with local school children.

The task that set the children apart from the Jays involved a mechanism which was counter-intuitive as it was hidden under an opaque surface. Neither the birds nor the children were able to learn how the mechanism worked, but the children were able to learn how to get the reward, whereas the birds were not.

The results of the study illustrate that children learn about cause and effect in the physical world in a different way to birds. While the Jay’s appear to take account of the mechanism involved in the task, the children are more driven by simple cause-effect relationships.

Lucy Cheke said, “This makes sense because it is children’s job to learn about new cause and effect relationships without being limited by ideas of what is or is not possible. The children were able to learn what to do to get the reward even if the chain-of-events was apparently impossible. Essentially, they were able to ignore the fact that it shouldn’t be happening to concentrate on the fact that it was happening. The birds however, found it much harder to learn what was happening because they were put off by the fact that it shouldn’t be happening.”

The tasks were a variation of Aesop’s fable that consisted of using a tube of water containing an out-of-reach prize. The subjects were required to use objects to displace the water so that the prize could be reached.

The first task involved two tubes, one filled with a prize amongst sawdust while the other tube contained a prize floating out of reach in water. The subject was presented with objects and was to choose which tube with which to drop the objects into: the sawdust or the water. Dropping objects into the tube containing sawdust obviously did not raise the level of the prize, whereas dropping the objects into the tube containing water created displacement and raised the prize within the reach of the subject.

The second task involved only one tube of water with a floating prize, but the subject was given a choice of what type of object to drop into the tube: an object that floats or another that sinks.

The final task presented the subject with an apparatus that consisted of one u-shaped tube with a wide arm and one narrow arm, and one single straight tube. These were imbedded in an opaque base so that the joining of the U-tube was hidden and the apparatus appeared to consist of two identical wide tubes with a narrow tube between them. Both the u-tube and the straight tube were filled with water such that the level was equal between them. The prize was inside the narrow arm of the u-tube, too narrow for the subject to insert an object to create displacement. Therefore, the subject was forced to pick one of the wider tubes on either side. If they picked the Wide arm of the u-tube, then the level of the prize would rise, but if they picked the single tube, it would not. Because the join of the u-tube was hidden, it appeared to the subjects as if dropping an item in one tube caused the level of water in a different tube to rise: which is impossible.

The birds were unable to complete this task, whereas the children performed at the same level as in the previous tasks, easily determining which tube raised the level of the water through trial and error.

Lucy added, “The Aesops fable paradigm provides an incredibly useful means by which to compare cause-effect learning with understanding of underlying mechanisms, i.e. folk physics. We are planning on extending this paradigm to really try to understand what’s going on in the heads of adults, children and animals when they deal with problems in the physical world.”

Lucy continued, “We would like to thank the staff, children and parents at Godmanchester community primary school for taking part in the study.”

Link:

http://www.eurekalert.org/pub_releases/2012-07/uoc-afu072512.php

Journal Reference:

  1. Lucy G. Cheke, Elsa Loissel, Nicola S. Clayton. How Do Children Solve Aesop’s Fable? PLoS ONE, 2012; 7 (7): e40574 DOI: 10.1371/journal.pone.0040574

Citation:

University of Cambridge (2012, July 25). Aesop’s fable unlocks how crows and kids think. ScienceDaily. Retrieved July 27, 2012, from http://www.sciencedaily.com­ /releases/2012/07/120725200330.htm

Increasing Dopamine in Brain’s Frontal Cortex Decreases Impulsive Tendency

ScienceDaily (July 25, 2012) — Raising levels of the neurotransmitter dopamine in the frontal cortex of the brain significantly decreased impulsivity in healthy adults, in a study conducted by researchers at the Ernest Gallo Clinic and Research Center at the University of California, San Francisco.


 

“Impulsivity is a risk factor for addiction to many substances, and it has been suggested that people with lower dopamine levels in the frontal cortex tend to be more impulsive,” said lead author Andrew Kayser, PhD, an investigator at Gallo and an assistant professor of neurology at UCSF. “We wanted to see if we could decrease impulsivity by raising dopamine, and it seems as if we can.”

The study was published on July 4 in the Journal of Neuroscience.

In a double-blinded, placebo-controlled study, 23 adult research participants were given either tolcapone, a medication approved by the Food and Drug Administration (FDA) that inhibits a dopamine-degrading enzyme, or a placebo. The researchers then gave the participants a task that measured impulsivity, asking them to make a hypothetical choice between receiving a smaller amount of money immediately (“smaller sooner”) or a larger amount at a later time (“larger later”). Each participant was tested twice, once with tolcapone and once with placebo.

Participants — especially those who were more impulsive at baseline — were more likely to choose the less impulsive “larger later” option after taking tolcapone than they were after taking the placebo.

Magnetic resonance imaging conducted while the participants were taking the test confirmed that regions of the frontal cortex associated with decision-making were more active in the presence of tolcapone than in the presence of placebo.

“To our knowledge, this is the first study to use tolcapone to look for an effect on impulsivity,” said Kayser.

The study was not designed to investigate the reasons that reduced dopamine is linked with impulsivity. However, explained Kayser, scientists believe that impulsivity is associated with an imbalance in dopamine between the frontal cortex, which governs executive functions such as cognitive control and self-regulation, and the striatum, which is thought to be involved in the planning and modification of more habitual behaviors.

“Most, if not all, drugs of abuse, such as cocaine and amphetamine, directly or indirectly involve the dopamine system,” said Kayser. “They tend to increase dopamine in the striatum, which in turn may reward impulsive behavior. In a very simplistic fashion, the striatum is saying ‘go,’ and the frontal cortex is saying ‘stop.’ If you take cocaine, you’re increasing the ‘go’ signal, and the ‘stop’ signal is not adequate to counteract it.”

Kayser and his research team plan a follow-up study of the effects of tolcapone on drinking behavior. “Once we determine whether drinkers can safely tolerate this medication, we will see if it has any effect on how much they drink while they’re taking it,” said Kayser.

Tolcapone is approved as a medication for Parkinson’s disease, in which a chronic deficit of dopamine inhibits movement.

Co-authors of the paper are Daicia C. Allen, BS, Ana Navarro-Cebrian, PhD, Jennifer M. Mitchell, PhD and senior author Howard L. Fields, MD, PhD, of the Gallo Center and UCSF.

The study was supported by funds from the Wheeler Center for the Neurobiology of Addiction, the U.S. Army Telemedicine and Advanced Technology Research Center, the Alcoholic Beverage Medical Research Foundation/The Foundation for Alcohol Research and the State of California.

Link:

http://www.ucsf.edu/news/2012/07/12408/increasing-dopamine-frontal-cortex-decreases-impulsive-tendency-ucsf-gallo

Journal Reference:

  1. Andrew S. Kayser,    Daicia C. Allen,    Ana Navarro-Cebrian,    Jennifer M. Mitchell,    and Howard L. Fields. Dopamine, Corticostriatal Connectivity, and Intertemporal Choice. The Journal of Neuroscience, 4 July 2012, 32(27):9402-9409 DOI: 10.1523/JNEUROSCI.1180-12.2012

Citation:

University of California – San Francisco (2012, July 25). Increasing dopamine in brain’s frontal cortex decreases impulsive tendency. ScienceDaily. Retrieved July 27, 2012, from http://www.sciencedaily.com­ /releases/2012/07/120725132443.htm

Piglets in Mazes Provide Insights Into Human Cognitive Development

ScienceDaily (July 25, 2012) — Events that take place early in life almost certainly have consequences for later cognitive development. Establishing the connections is difficult, however, because human infants cannot be used as laboratory subjects.


Rodney Johnson and his collaborators have developed an alternative model for studying infant brain development. “Assistant professor Ryan Dilger and I became interested in establishing the neonatal piglet as a model of human brain and cognitive development 3 or 4 years ago,” he said.

The idea came to Johnson when a former student, who was working for an infant formula company, asked about finding ways to determine differences in cognitive development between breast-fed infants and infants fed on formula.

“Human breast milk is the gold standard, but not every infant can be breast fed. A major goal for many infant formula companies is to improve the formulation to capture all of the benefits of breast milk,” he explained.

Johnson and his group had been working with rodent models to study learning and memory; they also had done some research looking at infectious disease in pigs. They wondered if it would be possible to develop tests to look at learning and memory using neonatal piglets.

It seemed like a reasonable idea because the growth and development of the piglet brain is similar to that of the human brain. The brain growth spurt is a perinatal event in both humans and pigs. At birth, the human brain is about 25 percent of adult size. In the first 2 years of life, it reaches 85 to 90 percent of adult size. The piglet brain grows in a similar way in a shorter time.

Johnson’s team first developed structural MRI methods for quantifying brain volume in the neonatal piglet. They then used these techniques to determine total brain and brain region volumes in a cohort of male and female domestic pigs, taking repeated measurements every 4 weeks starting at 2 weeks of age and finishing at near sexual maturity at 24 weeks of age.

They found that at 4 weeks, the piglet brain had grown to approximately 50 percent of its maximum volume, and it continued to grow rapidly for the next 8 weeks. Human infant brains grow in a similar way in the postnatal period. The results suggested that environmental insults during this period could affect brain structure and function.

The researchers’ next task was to develop a test to assess the piglets’ learning and memory, using a T-maze. They thought that this would be easy. They were wrong.

“It actually turned out to be very complicated because there were a lot of things that went wrong that we didn’t predict,” said Johnson. “For example, when we first started these studies, we used things like Skittles and apple slices as a reward because that’s what people using older pigs had done.”

The piglets, which were being fed on infant formula, had no interest in solid food, nor were they motivated to perform the tasks if the reward was the same as their regular food. They were, however, very willing to work for chocolate milk, specifically Nesquik™.

They did not receive the Nesquik™ anywhere else. “The idea is that piglets see chocolate milk only during the test and then it’s back to the standard formula,” said Johnson. “It helps increase their precision because it’s something they look forward to.”

Tests were conducted in a plus-shaped maze with one arm blocked off to leave a ‘T’ shape. Piglets were trained to locate the milk reward in a constant place in space as well as direction, using visual cues from outside the maze. When they learned to perform the task correctly the reward location was reversed, and the piglets were retested to assess learning and working memory. Correct choices decreased in the reversal phase but improved over time.

The results demonstrate that the T-maze can be used to measure cognitive abilities. Johnson and his collaborators will use these new tests to examine how stressors such as nutrient deficiencies and infections affect the human brain during this time of early, rapid growth.

“We want to know if this will alter the trajectory of normal development in a way that makes them more susceptible to behavioral disorders that occur later in life, such as autism and depression,” Johnson said. “Exposure to environmental insults early in life may also reduce stress resilience,” he added.

“There is a lot of interest in the concept of programming, the notion that things that occur early in life set that individual up for problems that occur many years later,” he continued. “Because the pig brain grows so much like a human brain, we thought this could be a very attractive model.”

The researchers have used the piglet model to demonstrate that an iron-deficient diet causes iron depletion in specific brain areas and is accompanied by cognitive deficits. They are using structural MRI and the T-maze task to study how viral pneumonia in the early neonatal period affects brain and cognitive development.

These data are complemented by measures of neuroinflammation, neurogenesis, and neuron morphology, procedures Johnson’s group has established in the neonatal piglet. Ryan Dilger is developing novel MRI procedures to measure biochemicals in the brain and to reveal how neural connections develop.

They are hoping to receive NIH funding to look at maternal viral infections. “We will infect pregnant gilts at the beginning of what would be the third trimester in humans and then study brain and cognitive development in the offspring,” Johnson said. “This is the type of interesting question we can pursue now that the piglet model is in place.”

Johnson said that it would be difficult to do this kind of research anywhere else.

“The Beckman Institute has been wonderful. We’re not MRI experts, nor do we want to be. However, we had a hypothesis and thought MRI technology could help us address it,” he said. “The support staff at Beckman has been really critical to helping develop the protocols.”

Johnson said that the other major advantages of the U of I are that the College of Agricultural, Consumer and Environmental Sciences has a unique research facility for housing pigs, and the Department of Animal Sciences maintains several swine farms that produce piglets on a regular basis.

The most recent research has been published online in Developmental Neuroscience.

The research is described in more detail in the following articles:

Conrad, M.S., R.N. Dilger and R.W. Johnson. 2012. “Brain growth of the Domestic Pig (Sus scrofa) from 2 to 24 weeks of Age: A Longitudinal MRI Study.” Developmental Neuroscience (in press, online first).

Elmore, M.R.P., R.N. Dilger, R.W. Johnson. 2012. “Place and Direction Learning in a Spatial T-maze test.” Animal Cognition 15:667-676.

Conrad, M.S., R.N. Dilger, A. Nickolls, and R.W. Johnson. 2012. “Magnetic Resonance Imaging of the Neonatal Piglet Brain.” Pediatric Research 71:179-184.

Link:

https://shared.aces.illinois.edu/content/piglets-mazes-provide-insights-human-cognitive-development

Citation:

University of Illinois College of Agricultural, Consumer and Environmental Sciences (2012, July 25). Piglets in mazes provide insights into human cognitive development. ScienceDaily. Retrieved July 27, 2012, from http://www.sciencedaily.com­ /releases/2012/07/120725132221.htm

Force of Habit: Stress Hormones Switch Off Areas of the Brain for Goal-Directed Behavior

ScienceDaily (July 25, 2012) — Cognition psychologists at the Ruhr-Universität together with colleagues from the University Hospital Bergmannsheil (Prof. Dr. Martin Tegenthoff) have discovered why stressed persons are more likely to lapse back into habits than to behave goal-directed. The team of PD Dr. Lars Schwabe and Prof. Dr. Oliver Wolf from the Institute for Cognitive Neuroscience have mimicked a stress situation in the body using drugs. They then examined the brain activity using functional MRI scanning.


 

The researchers have now reported in the Journal of Neuroscience that the interaction of the stress hormones hydrocortisone and noradrenaline shut down the activity of brain regions for goal-directed behaviour. The brain regions responsible for habitual behaviour remained unaffected.

Two stress hormones in use

In order to test the different stress hormones, the cognition psychologists used three substances — a placebo, the stress hormone hydrocortisone and yohimbine, which ensures that the stress hormone noradrenaline stays active longer. Part of the volunteers received hydrocortisone alone or just yohimbine, others both substances. A fourth group were administered a placebo. Altogether, the data of 69 volunteers was included in the study.

Goal-directed behaviour and habits investigated in the experiment

In the experiment, all participants — both male and female — learned that they would receive cocoa or orange juice as a reward if they chose certain symbols on the computer. After this learning phase, volunteers were allowed to eat as many oranges or as much chocolate pudding as they liked. “That weakens the value of the reward,” explained Schwabe. “Whoever eats chocolate pudding will lose the attraction to cocoa. Whoever is satiated with oranges, has less appetite for orange juice.” In this context, goal-directed behaviour means: Whoever has previously eaten the chocolate pudding, chooses the symbols leading to cocoa reward less frequently. Whoever is satiated with oranges, selects less frequently the symbols associated with orange juice. Based on previous results, the scientists assumed that only the combination of yohimbine and hydrocortisone attenuates goal-directed behaviour. They have now confirmed this hypothesis.

Combined effect of yohimbine and hydrocortisone

As expected, volunteers who took yohimbine and hydrocortisone did not behave goal-directed but according to habit. In other words, satiation with oranges or chocolate pudding had no effect. Persons who had taken a placebo or only one medication, on the other hand, behaved goal-directed and showed a satiating effect. The brain data revealed: The combination of yohimbine and hydrocortisone reduced the activity in the forebrain — in the so-called orbitofrontal and medial prefrontal cortex. These areas have been already previously associated with goal-directed behaviour. The brain regions which are important for habitual learning, on the other hand, were similarly active for all volunteers.

 

Link:

http://aktuell.ruhr-uni-bochum.de/pm2012/pm00253.html.en

Journal Reference:

  1. L. Schwabe, M. Tegenthoff, O. Höffken, O.Wolf. Simultaneous glucocorticoid and Noradrenergic activity disrupts the neural basis of goal-directed action in the human brain. Journal of Neuroscience, 2012 DOI: 10.1523/JNEUROSCI.1304-12.2012

Citation:

Ruhr-Universitaet-Bochum (2012, July 25). Force of habit: Stress hormones switch off areas of the brain for goal-directed behaviour. ScienceDaily. Retrieved July 27, 2012, from http://www.sciencedaily.com­ /releases/2012/07/120725090042.htm