FW: Decoupling object detection and categorization.

 

 

Feed: Journal of Experimental Psychology: Human Perception and Performance - Vol 36, Iss 5
Posted on: 23 August 2010 02:00
Author: Mack, Michael L.; Palmeri, Thomas J.
Subject: Decoupling object detection and categorization.

 

We investigated whether there exists a behavioral dependency between object detection and categorization. Previous work (Grill-Spector & Kanwisher, 2005) suggests that object detection and basic-level categorization may be the very same perceptual mechanism: As objects are parsed from the background they are categorized at the basic level. In the current study, we decouple object detection from categorization by manipulating the between-category contrast of the categorization decision. With a superordinate-level contrast with people as one of the target categories (e.g., cars vs. people), which replicates Grill-Spector and Kanwisher, we found that success at object detection depended on success at basic-level categorization and vice versa. But with a basic-level contrast (e.g., cars vs. boats) or superordinate-level contrast without people as a target category (e.g., dog vs. boat), success at object detection did not depend on success at basic-level categorization. Successful object detection could occur without successful basic-level categorization. Object detection and basic-level categorization do not seem to occur within the same early stage of visual processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)

View article...

[MATLAB] My first use of sendmail

The official Matlab blog featured a short article recently on a function that could be of use to some people: ‘sendmail’. If you set it up correctly, Matlab can send out e-mails to keep you updated on its progress while you’re away from your work computer, or automatically e-mail you the data as soon as a subject finishes an experiment.

 

http://blogs.mathworks.com/loren/2010/09/16/my-first-use-of-sendmail/?s_cid=fb_wall_loren_sendmail

 

 

For instance, to send from your kuleuven e-mail, you could use something like this.

 

address = 'yourname@gmail.com';                         % The e-mail address to which to send

subject = 'Matlab progress report';                     % The e-mail subject

message = 'Matlab finished creating your stimuli';      % The body of the message

attachname = 'stimuli.mat';                             % An attachment

mail = 'yourname@psy.kuleuven.be';                      % The e-mail address from which to send

username = 'u0000000';                                  % Your u-number

password = 'mypassword';                                % Your password

 

% Settings for kuleuven e-mail sending

setpref('Internet','E_mail',mail);

setpref('Internet','SMTP_Server','smtps.kuleuven.be');

setpref('Internet','SMTP_Username',username);

setpref('Internet','SMTP_Password',password);

 

props = java.lang.System.getProperties;

props.setProperty('mail.smtp.auth','true');

props.setProperty('mail.smtp.socketFactory.class', 'javax.net.ssl.SSLSocketFactory');

props.setProperty('mail.smtp.socketFactory.port','443');

 

% Sendmail example without attachment

sendmail(address,subject,message)

 

% Sendmail example with attachment

sendmail(address,subject,message,'stimuli.mat')

 

 

Beware though, having your KUL password saved in a plain text m-file can be a security risk. You could try to use a less sensitive e-mail account if this bothers you, or be more inventive in how you enter the password into the program (e.g., load it from a .mat file, make up or download a simple encryption routine,…).

 

Greetings,

Maarten

Fwd: Signal detection theory, uncertainty, and Poisson-like population codes

------- Forwarded message -------
From: "ScienceDirect Publication: Vision Research" <>
To:
Cc:
Subject: Signal detection theory, uncertainty, and Poisson-like population codes
Date: Wed, 08 Sep 2010 06:23:41 +0200

Publication year: 2010
Source: Vision Research, In Press, Accepted Manuscript, Available online 7 September 2010

Wei Ji, Ma

The juxtaposition of established signal detection theory models of perception and more recent claims about the encoding of uncertainty in perception is a rich source of confusion. Are the latter simply a rehash of the former? Here, we make an attempt to distinguish precisely between optimal and probabilistic computation. In optimal computation, the observer minimizes the expected cost under a posterior probability distribution. In probabilistic computation, the observer uses higher moments of the likelihood function of the stimulus on a trial-by-trial basis. Computation can be optimal without being probabilistic, and vice versa. Most signal detection theory models describe optimal computation....

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Article:

• http://www.sciencedirect.com/science?_ob=GatewayURL&_origin=IRSSCONTENT&_method=citationSearch&_piikey=S004269891000430X&_version=1&md5=ab8f30671b3d09ce997d455f3c117f3c

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Suggested reading by Kathleen

Neural bases of the non-conscious perception of emotional signals

Could be relevant for those interested in the influence of emotion on visual perception processes.

 

 

Feed: Nature Reviews Neuroscience - Issue - nature.com science feeds
Posted on: donderdag 2 september 2010 2:00
Author: Marco Tamietto
Subject: Neural bases of the non-conscious perception of emotional signals

 

Neural bases of the non-conscious perception of emotional signals Nature Reviews Neuroscience 11, 697 (2010). doi:10.1038/nrn2889 Authors: Marco Tamietto & Beatrice de Gelder Many emotional stimuli are processed without being consciously perceived. Recent evidence indicates that subcortical structures have a substantial role in this processing. These structures are part of a phylogenetically ancient pathway that has specific functional properties and that interacts with cortical processes. There is now

View article...

Suggested by Maarten

Situating visual search

A review/opinion on visual search tasks and the organization of the visual brain

 

 

Feed: ScienceDirect Publication: Vision Research
Posted on: vrijdag 17 september 2010 6:31
Author: ScienceDirect Publication: Vision Research
Subject: Situating visual search

 

Publication year: 2010 Source: Vision Research, In Press, Accepted Manuscript, Available online 15 September 2010 Ken, Nakayama , Paolo, Martini Visual search attracted great interest because its ease under certain circumstances seemed to provide a way to understand how properties of early visual cortical areas could explain complex perception without resorting to higher order psychological or neurophysiological mechanisms. Furthermore, there was the hope that properties of visual search itself might even reveal new cortical features or dimensions. The shortcomings of this perspective suggest that we abandon fixed canonical elementary particles of vision as well as a corresponding simple-to-complex cognitive architecture for vision. Instead recent research has suggested a different organization of the visual brain with putative high level processing occurring...

View article...

Suggested by Maarten

Nieuwe verkeersremmer: 3D-illusie van spelend meisje

 

 

http://www.standaard.be/artikel/detail.aspx?artikelid=DMF20100909_032

Research on horribly cute kittens is kind of horrible looking

A history lesson, probably not suitable for cat lovers...

 

 

Aan u verzonden door Sander via Google Reader:

 

 

Research on horribly cute kittens is kind of horrible looking

via Boing Boing door Maggie Koerth-Baker op 3-9-10

"In order to study the way that experience can influence the brain, there has been a great deal of research done on the visual cortex of the kitten."

Oh, this is going to end badly, isn't it?

This short documentary from the 1970s explains, in depth, some research that I mentioned earlier this year in a BoingBoing article on fetal senses. Long story short: Kittens are born blind and do a lot of their sight-linked brain development in the first few weeks after birth. Because of this, they make a handy model for studying how the brains of human fetuses form neural connections and how our sense of sight develops in the womb. It's important research that has helped medical science better understand how to care for premature human babies, besides adding valuable details to our understanding of the brain, in general.

Unfortunately, because kittens are adorable, said very important research looks almost comically evil when filmed. Seriously, this video is one "Thittens" joke away from working as a segment of Look Around You.

So, thanks, blorgggg (Thorgggg?), for sending this video in via Submitterator. I'm sure the Moderators will be thanking you (and me) as well. I do ask that, as we get into the inevitable discussion on animal research, you remember that the scientists involved did not raise kittens in completely dark rooms for sociopathic shits and giggles, but because they thought the potential benefits of the research outweighed the (mostly temporary) damage done to the kittens' visual abilities. You may disagree with that calculation—and you're welcome to do so. In fact, I think that complex discussion about ends and means in specific studies is valuable. And interesting. Far more so (on both counts) than simply labeling anyone who uses animals for research as a for-kicks abuser of fluffy baby kitties.

 

 

Dingen die u vanaf hier kunt doen:

• Abonneren op Boing Boing met Google Reader
• Aan de slag met Google Reader om eenvoudig al uw favoriete sites bij te houden

 

 

How neuroscience will change our view on consciousness

Victor Lamme on consciousness.

 

 

Sent to you by Frouke via Google Reader:

 

 

How neuroscience will change our view on consciousness

via : Articles recently published in by Lamme, Victor A. F. on 9/3/10

 

 

Things you can do from here:

• Subscribe to : Articles recently published in using Google Reader
• Get started using Google Reader to easily keep up with all your favorite sites

 

 

Reading between the Lines: How We See Hidden Objects

About amodal completion.

 

 

Sent to you by Frouke via Google Reader:

 

 

Reading between the Lines: How We See Hidden Objects

via Scientific American on 8/30/10

Imagine that you are looking at a dog that is standing behind a picket fence. You do not see several slices of dog; you see a single dog that is partially hidden by a series of opaque vertical slats. The brain's ability to join these pieces into a perceptual whole demonstrates a fascinating process known as amodal completion.

It is clear why such a tendency would have evolved. Animals must be able to spot a mate, predator or prey through dense foliage. The retinal image may contain only fragments, but the brain's visual system links them, reconstructing the object so the animal can recognize what it sees. The process seems effortless to us, but it has turned out to be one of those things that is horrendously difficult to program computers to do. Nor is it clear how neurons in the brain's visual pathways manage the trick.

[More]



Neuron - Brain - Dog - Biology - Animal

 

 

Things you can do from here:

• Subscribe to Scientific American using Google Reader
• Get started using Google Reader to easily keep up with all your favorite sites

 

 

Gestalt Principles Applied in Design

From today's Delicious hotlist.

 

 

Sent to you by Frouke via Google Reader:

 

 

Gestalt Principles Applied in Design

via Delicious hotlist by ani625 on 8/17/10

 Bookmark this on Delicious - Saved by ani625 to design gestalt webdesign psychology principles ui theory article blog reference - More about this bookmark

 

 

Things you can do from here:

• Subscribe to Delicious hotlist using Google Reader
• Get started using Google Reader to easily keep up with all your favorite sites

 

 

[Matlab] Isotropic dilation using the distance transform

Interesting article on Matlab’s official blog: take a binary foreground/background image, and compute for every single pixel whether it is within a certain range of a foreground pixel, really fast.

 

http://blogs.mathworks.com/steve/2010/08/16/isotropic-dilation-using-the-distance-transform/

 

I imagine this could have useful applications for Matlab users, even beyond image processing. For instance, it could be used to randomize positions in grouping displays while respecting a certain minimum distance.

 

Maarten

FW: Dynamic Norm-based Encoding for Unfamiliar Shapes in Human Visual Cortex

Uit eigen huis…

 

Katrien

 

Feed: MIT Press Journals: Journal of Cognitive Neuroscience: Table of Contents
Posted on: 31 August 2010 19:37
Author: journals-info@mit.edu (Sven Panis et al)
Subject: Dynamic Norm-based Encoding for Unfamiliar Shapes in Human Visual Cortex

 

Journal of Cognitive Neuroscience, Volume 0, Issue 0, Page 1-15, Early Access.

View article...

Fwd: Age, eye movement and motion discrimination.

------- Forwarded message -------
From: "Vision Research" <>
To:
Cc:
Subject: Age, eye movement and motion discrimination.
Date: Fri, 20 Aug 2010 00:00:00 +0200

Authors: O'Connor E, Margrain TH, Freeman TC Age is known to affect sensitivity to retinal motion. However, little is known about how age might affect sensitivity to motion during pursuit. We therefore investigated direction discrimination and speed discrimination when moving stimuli were either fixated or pursued. Our experiments showed: 1) age influences direction discrimination at slow speeds but has little affect on speed discrimination; 2) the faster eye movements made in the pursuit conditions produced poorer direction discrimination at slower speeds, and poorer speed discrimination at all speeds; 3) regardless of eye movement condition, observers always combined retinal and extra-retinal motion signals to make their judgements. Our results support the idea that performance in th...

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Article:

• http://www.medworm.com/index.php?rid=3907903&cid=s_35430_30_f&fid=35430&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20732343%26dopt%3DAbstract

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