Tag Archives: Global versus local visual processing

Australian study finds evidence suggesting that use of recreational drug ecstasy will damage face perception ability

White, Claire, Edwards, Mark, Brown, John and Bell, Jason The impact of recreational MDMA ‘ecstasy’ use on global form processing. Journal of Psychopharmacology. August 20, 2014

Published online before print August 20, 2014, doi: 10.1177/0269881114546709

http://jop.sagepub.com/content/early/2014/08/18/0269881114546709.abstract?rss=1

 

Yeang, Lily Ecstasy use affects ability to detect faces, shapes and patterns. ScienceNetwork Western Australia.

http://www.sciencewa.net.au//topics/health-a-medicine/item/3085-ecstasy-use-affects-ability-to-detect-faces-shapes-and-patterns

 

One should bear in mind that this study only used a small number of long-term ecstasy users as subjects (6) and these people also used other drugs, which could have had an influence, and it appears that actual faces or images of faces were not a part of the study, which tested the type of visual processing of which face processing is apparently one example. The full text of the study is behind a paywall, so I’ve not yet read it in full. The study is certainly interesting, as it displays internal consistency in the findings which are also apparently compatible with the findings of other studies.

This study is just another good reason why the testing of visual processing, including abilities such as face memory and global form processing, should ideally be an element of the job recruitment selection process for many jobs. “If global form processing is damaged or deficient then our speed and accuracy in recognizing objects in the environment, and our ability to navigate amongst those objects, will be impaired.” So does that mean that long-term ecstasy users aren’t OK to operate heavy machinery or to drive? I think it is anyone’s guess, and there is no law enforcement or job screening process that I am aware of that is likely to detect people with this kind of visual processing disability, until they have a crash. If you know otherwise, please leave a comment and we we’ll all be the wiser.

UWA seminar on Tuesday could be interesting

“In this seminar, I will present data on three inter-related aspects of attentional focusing: the spatiotemporal dynamics of focusing, object representations and their role in focusing, and the consequences of focusing on visual processing.”

I’m quite interested in visual processing, although I’m not a professional researcher in psychology. I’m not a professional researcher in anything at all. I don’t get paid, I think in my own time. If I were to follow the current zeitgeist I’d be playing sport instead of thinking (Australia has a federal minister for sport but none for science I believe), but I’m not one to follow trends.

The speaker of this upcoming seminar at UWA is Dr. Lisa Jefferies. Unless I am mistaken, another area of research that she has explored is face perception, but there is no hint that face perception will be covered in this seminar.

To be (broad) or not to be (broad): The dynamics of attentional focusing. Science Network Western Australia. http://www.sciencewa.net.au/component/ohanah/to-be-broad-or-not-to-be-broad-the-dynamics-of-attentional-focusing.html

Lisa Jefferies http://www2.psych.ubc.ca/~ennslab/Vision_Lab/Lisa_Jefferies.html

Colloquium:  To be (broad) or not to be (broad).  http://events.uwa.edu.au/event/20130910T045244Z-2131-4946@events.uwa.edu.au/whatson/Faculty%20of%20Education

Face recognition and the Navon Task

I was looking at a Wikipedia article and discovered a claim that priming with Navon figures aides the recognition of faces, which seems like something that might be a clue to understanding prosopagnosia or a treatment for it, but then I noticed that this entire section appears to be based on the findings of only one study:  http://en.wikipedia.org/wiki/Global_precedence#Faces

Dr Ashok Jansari’s search for super-recognizers finds seven – article in Der Spiegel

According to the English translation of this article, which is available through the Superrecognizers website belonging to Dr Jansari and his team at the University of East London, the search for super-recognizers in London that was conducted late last year into early 2012 yielded 7 super-recognizers out of the 725 people who participated in the testing study at the Science Museum in London, including a surprising find that the brother of Dr Jansari is one of the seven. How strange is that? So, we know that one of the seven super-recognizers is male. What are the genders of the others? I don’t think it says in this article.

Also of interest in the article is information about the elite group of super-recognizer police in London’s Metropolitan Police, with interviews with super-super-recognizer Idris Bada and Detective Chief Inspector Mick Neville.

Hoflinger, Laura Hirnforschung – Superhelden aus dem Museum. Der Spiegel. Volume 11 2012 p.129-131.  http://www.superrecognizers.com/storage/Der%20Spiegel_super-recognizers_March2012.pdf

An English translation can be accessed from here:  http://www.superrecognizers.com/in-the-news/

This is a quote from the translation:

“The neuropsychologist Jansari suspects that his brother and the other super-recognizers process faces in a rather holistic way; they do not focus as much on single parts of the face, like the nose, mouth or eyes.”

If I’m a super-recognizer, then I don’t know if this idea of super-recognizers having more holistic perception with less focus on individual elements explains the difference between us and people with normal levels of ability. I do very much notice individual elements of faces, consciously and unconsciously, as well as recognizing whole faces in a way that feels automatic and uncontrolled. I will notice if different people have mouths or ears that look similar and also distinctive. I recall that a boy I knew when I was a teen and he was a child had a William Shatner mouth, which is a quite an unusual type of mouth where the upper lip looks the larger. Barack Obama and Nelson Mandela seem to have very similar smiles and lower faces, but not identical faces. I think the difference between a super-recognizer and a regular recognizer might be that the former does both holisitc and detailed perception well and also in a well-integrated manner. I believe enhanced brain wiring akin to synaesthesia might be the basis of this enhanced integration of both modes of perception. I suspect that an emphasis on perceiving faces feature-by-feature might be more characteristic of poor face recognition than good face recognition. In the recent CBS 60 Minutes story about prosopagnosia and super-recognizers the prosopagnosic artist Chuck Close was asked to identify the faces of some famous people. He did manage to identify some of the faces and he explained how he did it. He identified Jay Leno from his very unusual chin and picked Tiger Woods from his lips.

It is interesting to see for the first time researchers giving estimates of how common (or rare) super-recognizers might be in the population at large. The seven in seven hundred and twenty-five people tested in the London study suggests that super-recognizers are made by mother nature at a rate of just over 1% of the population, while Dr Jansari’s team give an estimate of 2% for super-recognizers at their website http://www.superrecognizers.com/about/  I guess it all depends on definitions and cut-off points, which are arbitrary. At levels of one or two percent super-recognizers are rare enough to constitute some kind of elite, worth identifying or recruiting if the trait is found to have some value or utility, but are also not so rare that anyone can dismiss the possibility that one could encounter or find a super-recognizer in their community or workplace or social circle. Perhaps super-recognizers should form some kind of association or society or club. The future is anyone’s guess, as this area of scientific inquiry is shiny and new, and we are dealing with a concept that is only a few years old.

At the beginning of the Der Spiegel article there are six photographs of famous people when they were children, which can be used as a mini Before They Were Famous Test if you don’t scroll down too soon and see who they are. How many of them are you able to identify? I picked three of them correctly, and couldn’t guess at the others who were not unknown to me but weren’t hugely familiar either, as I’m not as European as the magazine is. I had seen the photo of the little boy with the big hat before and knew who it is. The thing that really struck me about this photo is the apparent abnormality with the child’s eyes. They don’t match – one is much darker than the other, which seems rather worrying. Some people naturally have irises of different colours, but it isn’t a good thing if pupil sizes don’t match.

I’ve not mentioned before that there are three different types of things to look at which seem to catch my eye in ways that are a maybe bit extreme or distracting. These things are faces (animals and human), cars travelling at a speed of around 40 KPH (especially the wheels), and eyes. I simply cannot abide the sight of eyes that point in different directions, even in the slightest. Glass eyes are the worst, and lazy eyes make me feel ill, even if the owner of them is the nicest person in the world. And some apparently healthy and normal people have eyes that seem to be very slightly out. This seems to happen more often in people whose eyes protrude slightly, for whatever reason, and this type of thing seems to be unusually common among a particular ethnic group from the South Pacific. Another eye issue that sets me on edge is eyes with pupils that don’t look right, because one looks bigger in one eye than the other, or they both seem to be too dilated, bringing to mind the image of a pet cat in an aggressive mood. Have you ever read the classic short story The Tell-Tale Heart by Edgar Allan Poe? A bad eye can certainly be quite a distraction, but it isn’t only eye imperfection which catches my eye. I can also become quite distracted by the perfection of good eyes in some circumstances. Newborn babies are such lovely little things with soft, perfect skin, but they are quite limited in things that they can do to express themselves physically. Their limb movements seem random and quite uncontrolled, but the way their eyes move is a display of how perfectly a baby has been put together by nature, because even though the baby might look around in an apparently uncontrolled manner, his or her eyes will usually match perfectly in their movements. This I find fascinating, in a way that seems to owe more to instinct than to intellect. Maybe all mothers find the eyes of young babies fascinating in a way that is strangely compelling. I’m just glad that I don’t live on an island in the South Pacific.