Featured Research

from universities, journals, and other organizations

How Believing Can Be Seeing: Context Dictates What We Believe We See

Date:
February 19, 2008
Source:
University College London
Summary:
Scientists have found the link between what we expect to see, and what our brain tells us we actually saw. The study reveals that the context surrounding what we see is all important -- sometimes overriding the evidence gathered by our eyes and even causing us to imagine things which aren't really there.

The same dim vertical target rectangle centered in two different contexts is more visible in the left vague context.
Credit: Image courtesy of University College London

Scientists at UCL (University College London) have found the link between what we expect to see, and what our brain tells us we actually saw. The study reveals that the context surrounding what we see is all important -- sometimes overriding the evidence gathered by our eyes and even causing us to imagine things which aren't really there.

Related Articles


The paper reveals that a vague background context is more influential and helps us to fill in more blanks than a bright, well-defined context. This may explain why we are prone to 'see' imaginary shapes in the shadows when the light is poor.

Eighteen observers were asked to concentrate on the centre of a black computer screen. Every time a buzzer sounded they pressed one of two buttons to record whether or not they had just seen a small, dim, grey 'target' rectangle in the middle of the screen. It did not appear every time, but when it did appear it was displayed for just 80 milliseconds (80 one thousandths of a second).

"People saw the target much more often if it appeared in the middle of a vertical line of similar looking, grey rectangles, compared to when it appeared in the middle of a pattern of bright, white rectangles. They even registered 'seeing' the target when it wasn't actually there," said Professor Zhaoping, lead author of the paper. "This is because people are mentally better prepared to see something vague when the surrounding context is also vague. It made sense for them to see it -- so that's what happened. When the target didn't match the expectations set by the surrounding context, they saw it much less often.

"Illusionists have been alive to this phenomenon for years," continued Professor Zhaoping. "When you see them throw a ball into the air, followed by a second ball, and then a third ball which 'magically' disappears, you wonder how they did it. In truth, there's often no third ball - it's just our brain being deceived by the context, telling us that we really did see three balls launched into the air, one after the other.

"Contrary to what one might expect, it is a vague rather than a bright and clearly visible context that most strongly permits our beliefs to override the evidence and fill in the blanks. In fact, a bright and clearly visible context actually overrides the evidence in the opposite direction - suppressing our 'seeing' of the vague target even when it is present.

"Mathematical modelling suggests that visual inference through context is processed in the brain beyond the primary visual cortex. By starting with a relatively simple experiment such as this, where visual input can be more easily and systematically manipulated, we are gaining a better understanding of how context influences what we see. Further studies along these lines can hopefully enable us to dissect the workings behind more complex and wondrous illusions."

Journal reference: Filling-in and suppression of visual perception from context -- a Bayesian account of perceptual biases by contextual influences, by Professor Li Zhaoping and Dr Li Jingling appears in the 15 February issue of the journal PLoS Computational Biology.

The research was funded by the Gatsby Charitable Foundation and a Cognitive Science Foresight Grant.


Story Source:

The above story is based on materials provided by University College London. Note: Materials may be edited for content and length.


Cite This Page:

University College London. "How Believing Can Be Seeing: Context Dictates What We Believe We See." ScienceDaily. ScienceDaily, 19 February 2008. <www.sciencedaily.com/releases/2008/02/080215103210.htm>.
University College London. (2008, February 19). How Believing Can Be Seeing: Context Dictates What We Believe We See. ScienceDaily. Retrieved January 26, 2015 from www.sciencedaily.com/releases/2008/02/080215103210.htm
University College London. "How Believing Can Be Seeing: Context Dictates What We Believe We See." ScienceDaily. www.sciencedaily.com/releases/2008/02/080215103210.htm (accessed January 26, 2015).

Share This


More From ScienceDaily



More Mind & Brain News

Monday, January 26, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

How Technology Is Ruining Snow Days For Students

How Technology Is Ruining Snow Days For Students

Newsy (Jan. 25, 2015) More schools are using online classes to keep from losing time to snow days, but it only works if students have Internet access at home. Video provided by Newsy
Powered by NewsLook.com
Weird Things Couples Do When They Lose Their Phone

Weird Things Couples Do When They Lose Their Phone

BuzzFeed (Jan. 24, 2015) Did you back it up? Do you even know how to do that? Video provided by BuzzFeed
Powered by NewsLook.com
Smart Wristband to Shock Away Bad Habits

Smart Wristband to Shock Away Bad Habits

Reuters - Innovations Video Online (Jan. 23, 2015) A Boston start-up is developing a wristband they say will help users break bad habits by jolting them with an electric shock. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Amazing Technology Allows Blind Mother to See Her Newborn Son

Amazing Technology Allows Blind Mother to See Her Newborn Son

RightThisMinute (Jan. 23, 2015) Not only is Kathy seeing her newborn son for the first time, but this is actually the first time she has ever seen a baby. Kathy and her sister, Yvonne, have been legally blind since childhood, but thanks to an amazing new technology, eSight glasses, which gives those who are legally blind the ability to see, she got the chance to see the birth of her son. It&apos;s an incredible moment and an even better story. Video provided by RightThisMinute
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins