HomeLatest ThreadsGreatest ThreadsForums & GroupsMy SubscriptionsMy Posts
DU Home » Latest Threads » CatLady78 » Journal
Page: « Prev 1 2 3 4 5 6 7 8 Next »


Profile Information

Gender: Female
Current location: India
Member since: Thu Jun 18, 2020, 11:40 AM
Number of posts: 497

About Me

I am an old-timer. I posted here as nam78_two for 4-5 years (2004 or 5 to 2009-10) in the Bush, Obama years.

Journal Archives

Visual Working Memory is Hierarchically Structured


According to the hierarchical encoding framework, it will be easier to recall the items in the first picture, rather than in the third one, due to the lower range of triangle orientations. Credit: Utochkin, I. S., & Brady, T. F. (2020). Individual representations in visual working memory inherit ensemble properties. Journal of Experimental Psychology: Human Perception and Performance, 46(5), 458-473.

Visual working memory is hierarchically structured

Researchers from HSE University and the University of California San Diego, Igor Utochkin and Timothy Brady, have found new evidence of hierarchical encoding of images in visual working memory. It turns out that the precision of remembering and recalling individual objects in a group is affected by ensemble representations—the mean and standard deviation of all objects in the group. The study has been published in Journal of Experimental Psychology: Human Perception and Performance.

Visual working memory stores information about a limited number of perceived objects during a short period of time while we are involved in a task exploiting this information. For example, you will be using visual working memory if you are asked to memorize circles on the screen and then recall the size of one of them.

It is known that working memory capacity is limited: we are capable of remembering about three or four objects on average. Many theories assume that each object is memorized, stored and forgotten in working memory independently of the other objects. In contrast, proponents of the hierarchical encoding framework do not agree with this assumption. According to this framework, memory encodes not only the information on each item separately, but also the information on the group of objects together. This generalized representation about the group is coded in ensemble summary statistics. The visual system can calculate the mean and standard deviation of all features of the items present.

The researchers carried out a series of experiments that demonstrate a strong impact of ensemble statistics on individual items' memory. In one of the experiments, the participants were shown a group of four isosceles triangles with different apex orientations. The range of apex orientations varied: they were pointing in about the same direction, or in completely different ones. The higher the variability, the more difficult it is to calculate the mean orientation.

"This says for a fact that even as we try to memorize items individually, our working memory also stores the summary of the whole group," commented Igor Utochkin, professor at the HSE School of Psychology. If precise information about a specific item isn't in memory, one uses the ensemble statistics to recall the approximate characteristics of the object. The more precise these statistics are, the more precise the response concerning that object is.

Hmm...see I would have thought that middle image would be the hardest to keep in memory. There is almost a clockwise rotation pattern in the 3rd that makes it easier to recollect than that middle one which is just chaotic (but then again I am not measuring it with any precision).

Thank you-this is so disturbing

Humane slaughter and humane living conditions are the minimum.

This is completely irrational. As a society we are too glib about animal suffering. The animals lowest in our messed up hierarchy are no less sentient than cats or dogs. This should shock and disturb any civilized society. People are suffering too but that does not excuse torture on this scale.
A society with access to technology imho is on a very messed up track if we don't see something very wrong with cruelty like this inflicted on living organisms this large (chickens, pigs) and on this scale.

That doesn't bode well for humans either..sigh..

This is horrible-we are a nightmarishly cruel species

This has to be stopped.


I suppose this will be the next 100 years...more articles about one species after another going extinct...


I actually post science here to an extent to force myself to read more stuff and in more depth.
I made an embarassing error in an article I just posted on something I have a passing familiarity with-hair cell stereocilia. But it is making me read that paper properly.
Or I increasingly never do any reading outside a very narrow area in science and tied to specific problem solving.

As long as I don't leave anything inaccurate up here, it is an exercise that helps me. I'd hate to give people wrong information. So it forces me to check my work.

I am glad you contacted them and made these points

Thank you for doing that. I disagree very little with your points or with those by RobinA. I hope you prevail.

That said, I do still support PP for the simple reason that they are the most high profile organization that does the work they do. If they diluted their actual positions on birth control, abortion, gave a wider berth to religion/superstition/ anti science etc that would cause me real concern.

I simply do not know another org of that stature. They face constant smearing (as does Sanger) by religious zealots who are fairly tolerant of actual racists but suddenly become concerned about racism or the poor, when it is PP, Sanger, Paul Ehrlich, David Attenborough, Michael Moore...just about any feminist, environmentalist, scientist or liberal they can smear.
It is as hollow as Tucker Carlson's populism.

It is a cynical ploy and has little to do with concerns over the rights of the poor, racism etc.

Love Bill Nye.nt

This is a great post

Thank you for expressing these ideas so well. If we have lost the ability to comprehend shades of grey as a species, that is net a win for rightist thinking.

The Gliding Motion of Toxoplasma gondii

This is neat. These scientists have further characterized the movement of Toxoplasma gondii, which uses a type of gliding movement that is faster than a lot of cell movement (which is analogous to crawling). The cell anchors itself at a couple of points on a surface which mimics the exterior of the cell. It contracts and builds up spring energy in its cytoskeleton, which it then uses to propel itself forward upon the breaking of those same attachments.
(Apologies for the clumsiness in my writing-my scientific communication skills are a work in progress. I am still a little confused by this paper. I will update this if I have said anything inaccurate.)


Image credit: The Tardieux lab (it is from the paper).

If you're a cat owner, you might have heard of Toxoplasma gondii, a protozoan that sometimes infects humans through contact with contaminated feces in litterboxes. Although harmless to most people, T. gondii can cause serious illness or death in immunocompromised individuals or fetuses of infected pregnant women. Now, researchers reporting in ACS Nano have studied how the microorganism glides so swiftly through mammalian tissues during an infection.

To find out, the researchers combined several types of high-resolution and high-speed 2-D and 3-D live imaging with force microscopy methods. They examined the parasites' movements through collagen fibers that mimicked the extracellular matrix—a dense network of proteins that surrounds cells in tissues. Tachyzoites squeezed through the collagen meshwork by first pausing and forming a kink in the front part of their bodies. Then, the cell bodies contracted, and the parasites surged forward with a spring-like motion. Delving deeper with the help of photomicropatterning and machine learning approaches, the researchers found that these movements were caused by the formation and breakage of specific attachments between the protozoans and collagen fibers, resulting in the buildup of contractile forces in the parasites' cytoskeletons. When the front tip of a parasite released its hold on the fibers, it sprung forward with a super-fast, helical glide.

Neat video:

I disagree with the attacks on Sanger

Anti-abortion groups have been attacking her for a long time:


I get why PP has to do this. However, I disagree with the attacks on Sanger. They lack perspective. If she was alive today I would imagine she would be staunchly opposed to racism. She was a progressive leader by the standards of her time. The attacks on her are mostly driven by actual racists. Where that is not the case, I just have a different view-point. Fifty years from now a lot of us will be condemned for our beliefs and ways today-especially the ignoring of environmental issues and our lack of concern for other species and for future generations.
Go to Page: « Prev 1 2 3 4 5 6 7 8 Next »