Working-memory capacity protects model-based learning from stress.

Working-memory capacity protects model-based learning from stress.
Proc Natl Acad Sci U S A. 2013 Dec 24;110(52):20941-6.
Otto AR, et al.

Accounts of decision-making have long posited the operation of separate, competing valuation systems in the control of choice behavior.
Recent theoretical and experimental advances suggest that this classic distinction between habitual and goal-directed (or more generally, automatic and controlled) choice may arise from two computational strategies for reinforcement learning, called model-free and model-based learning. Popular neurocomputational accounts of reward processing emphasize the involvement of the dopaminergic system in model-free learning and prefrontal, central executive-dependent control systems in model-based choice.
Here we hypothesized that the hypothalamic-pituitary-adrenal (HPA) axis stress response–believed to have detrimental effects on prefrontal cortex function–should selectively attenuate model-based contributions to behavior.
To test this, we paired an acute stressor with a sequential decision-making task that affords distinguishing the relative contributions of the two learning strategies. We assessed baseline working-memory (WM) capacity and used salivary cortisol levels to measure HPA axis stress response. We found that stress response attenuates the contribution of model-based, but not model-free, contributions to behavior. Moreover, stress-induced behavioral changes were modulated by individual WM capacity, such that low-WM-capacity individuals were more susceptible to detrimental stress effects than high-WM-capacity individuals. These results enrich existing accounts of the interplay between acute stress, working memory, and prefrontal function and suggest that executive function may be protective against the deleterious effects of acute stress.

Abductive reasoning: taking your best shot

Abductive reasoning: taking your best shot
Butte College. 10/28/08

Abductive reasoning typically begins with an incomplete set of observations and proceeds to the likeliest possible explanation for the set. Abductive reasoning yields the kind of daily decision-making that does its best with the information at hand, which often is incomplete.

A medical diagnosis is an application of abductive reasoning: given this set of symptoms, what is the diagnosis that would best explain most of them?

While cogent inductive reasoning requires that the evidence that might shed light on the subject be fairly complete, whether positive or negative, abductive reasoning is characterized by lack of completeness, either in the evidence, or in the explanation, or both.
A patient may be unconscious or fail to report every symptom, for example, resulting in incomplete evidence, or a doctor may arrive at a diagnosis that fails to explain several of the symptoms. Still, he must reach the best diagnosis he can.

The abductive process can be creative, intuitive, even revolutionary.
Einstein’s work, for example, was not just inductive and deductive, but involved a creative leap of imagination and visualization that scarcely seemed warranted by the mere observation of moving trains and falling elevators.
In fact, so much of Einstein’s work was done as a “thought experiment” (for he never experimentally dropped elevators), that some of his peers discredited it as too fanciful.
Nevertheless, he appears to have been right-until now his remarkable conclusions about space-time continue to be verified experientially.

Thagard, Paul and Cameron Shelley.
“Abductive reasoning: Logic, visual thinking, and coherence.”
Waterloo, Ontario: Philosophy Department, Univerisity of Waterloo,
1997. June 2, 2005.

In abductive reasoning, unlike in deductive reasoning, the premises do not guarantee the conclusion.

cited by:
University of Pennsylvania
7.1 The Design Process > Design Thinking
Balance of analytical & creative:
– Abductive reasoning

cited by:
Data Visualization (July 2015)
by John C. Hart
University of Illinois at Urbana-Champaign

Rise of the Robots

Rise of the Robots
Mar 29, 2014

Special report: Robots

Immigrants from the future

The build-up
Good and ready

Business service robots
The invisible unarmed

Labour markets
A mighty contest

Domestic service robots
Seal of approval

That thou art mindful of him

Synthesis of a Designer Eukaryotic Chromosome

Total Synthesis of a Functional Designer Eukaryotic Chromosome
Science. 27 March 2014

Rapid advances in DNA synthesis techniques have made it possible to engineer viruses, biochemical pathways and assemble bacterial genomes. Here, we report the synthesis of a functional 272,871–base pair designer eukaryotic chromosome, synIII, which is based on the 316,617–base pair native Saccharomyces cerevisiae chromosome III.
Changes to synIII include TAG/TAA stop-codon replacements, deletion of subtelomeric regions, introns, transfer RNAs, transposons, and silent mating loci as well as insertion of loxPsym sites to enable genome scrambling.
SynIII is functional in S. cerevisiae. Scrambling of the chromosome in a heterozygous diploid reveals a large increase in a-mater derivatives resulting from loss of the MATα allele on synIII.
The complete design and synthesis of synIII establishes S. cerevisiae as the basis for designer eukaryotic genome biology.

related articles:

Scientists Move Closer to Inventing Artificial Life
Synthetic biology advances with a man-made chromosome inserted into live brewer’s yeast.
National Geographic. March 27, 2014

Student Assembly Drives Yeast Project
Science 28 March 2014: 343(6178):1429 (PAID)

Building the Ultimate Yeast Genome
Elizabeth Pennisi
Science 28 March 2014: 1426-1429. (PAID)



We want to increase our loyalty and engagement with strong gamification platform to further incentivize our already loyal fan base to visit Pley for more than just LEGO rental, but to have a complete 360 experience from picking their set to sharing their experience with other members through fun interactive features.


Collaborative pioneer: Inside interview with Ruxandra Creosteanu at Babele
What tools do you use to foster collaboration between entrepreneurs?
The other key tool is gamification: which is a way to make the whole process more meaningful and fun for everyone. To incentivize people to work together in the most effective way, the platform will include a credit system. This system will reward mentors and entrepreneurs according to the level of contribution to the projects inside the platform. It will enable entrepreneurs to find valuable team members among fans and supporters.

Mai Nozipo, For Ngoma, Hosho …

Mai Nozipo, For Ngoma, Hosho & String Quartet (“Mother Nozipo”)
by Maraire, Dumisani
on Kronos Quartet, Pieces Of Africa


Similar Composers:

  • Nick Takenobu Ogawa
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