Showing posts with label Memory. Show all posts
Showing posts with label Memory. Show all posts
Tuesday, March 23, 2010
Monday, December 7, 2009
Photo is Worth a Thousand Ways to Change Your Memory by David DiSalvo
This article has a lot to say to actors because it reinforces the need for images of the given circumstances.
Most of us realize that memory is fallible. We forget things all the time–car keys, passwords, whether we turned off the oven, etc. But how many of us would admit that our memory is susceptible to change from the outside? That’s different from simply forgetting–something everyone does on their own–because someone else changing our memory requires “getting in our heads” so to speak, right?
If you’ve read this blog for any length of time, you know I’m about to tell you that not only is it possible, it’s probable. And it doesn’t even take very much effort to accomplish–just a few images and a little time.
A recent study in the journal Applied Cognitive Psychology tested whether showing people photos of completed actions–such as a broken pencil or an opened envelope–could influence them to believe they’d done something they had not, particularly if they were shown the photos multiple times.
Participants were presented with a series of objects on a table, and for each object were asked to either perform an action or imagine performing an action (i.e. “crack the walnut”). One week later, the same participants were brought back and randomly presented with a series of photos on a computer screen, each of a completed action (i.e. a cracked walnut), either one, two or three times. Other participants were not shown any photos.
One week later, they were brought back to complete a memory test in which they were presented with action phrases (i.e. “I cracked a walnut”) and asked to answer whether they had performed the action, imagined performing it, or neither, and rate their confidence level for each answer on a scale of one to four.
The results: the more times people were exposed to a photo of a completed action, the more often they thought they’d completed the action, even though they had really only imagined doing it. Those shown a photo of a completed action once were twice as likely to erroneously think they’d completed the action than those not shown a photo at all. People shown a photo three times were almost three times as likely as those not shown a photo.
Two factors in this study speak to the malleability of memory. The first is duration of time. The experiment was carried out with a week between each session, enough time for the specific objects and actions to become a little cloudy in memory, but not enough time to be forgotten. This lines up well with real-world situations, such as someone providing eye-witness testimony, in which several days if not weeks might elapse between recollections of events.
The second factor is repeat exposure to images. The study showed that even just one exposure to a photo of a completed action strongly influenced incorrect memory. Multiple exposures significantly increased the errors. One real-world takeaway from this result is potentially alarming: the possibility of using images to alter someone’s memory of a face or other critical element such that his/her testimony is tainted.
A similar study discussed here tackled the same sort of memory issues with video instead of photos, and found a similar result. Both studies point to a realization becoming clearer with time: memory is far more changeable than most of us realize.
Henkel, L. (2009). Photograph-induced memory errors: When photographs make people claim they have done things they have not Applied Cognitive Psychology DOI: 10.1002/acp.1644
Photo is Worth a Thousand Ways to Change Your Memory
Most of us realize that memory is fallible. We forget things all the time–car keys, passwords, whether we turned off the oven, etc. But how many of us would admit that our memory is susceptible to change from the outside? That’s different from simply forgetting–something everyone does on their own–because someone else changing our memory requires “getting in our heads” so to speak, right?If you’ve read this blog for any length of time, you know I’m about to tell you that not only is it possible, it’s probable. And it doesn’t even take very much effort to accomplish–just a few images and a little time.
A recent study in the journal Applied Cognitive Psychology tested whether showing people photos of completed actions–such as a broken pencil or an opened envelope–could influence them to believe they’d done something they had not, particularly if they were shown the photos multiple times.
Participants were presented with a series of objects on a table, and for each object were asked to either perform an action or imagine performing an action (i.e. “crack the walnut”). One week later, the same participants were brought back and randomly presented with a series of photos on a computer screen, each of a completed action (i.e. a cracked walnut), either one, two or three times. Other participants were not shown any photos.
One week later, they were brought back to complete a memory test in which they were presented with action phrases (i.e. “I cracked a walnut”) and asked to answer whether they had performed the action, imagined performing it, or neither, and rate their confidence level for each answer on a scale of one to four.
The results: the more times people were exposed to a photo of a completed action, the more often they thought they’d completed the action, even though they had really only imagined doing it. Those shown a photo of a completed action once were twice as likely to erroneously think they’d completed the action than those not shown a photo at all. People shown a photo three times were almost three times as likely as those not shown a photo.
Two factors in this study speak to the malleability of memory. The first is duration of time. The experiment was carried out with a week between each session, enough time for the specific objects and actions to become a little cloudy in memory, but not enough time to be forgotten. This lines up well with real-world situations, such as someone providing eye-witness testimony, in which several days if not weeks might elapse between recollections of events.
The second factor is repeat exposure to images. The study showed that even just one exposure to a photo of a completed action strongly influenced incorrect memory. Multiple exposures significantly increased the errors. One real-world takeaway from this result is potentially alarming: the possibility of using images to alter someone’s memory of a face or other critical element such that his/her testimony is tainted.
A similar study discussed here tackled the same sort of memory issues with video instead of photos, and found a similar result. Both studies point to a realization becoming clearer with time: memory is far more changeable than most of us realize.
Henkel, L. (2009). Photograph-induced memory errors: When photographs make people claim they have done things they have not Applied Cognitive Psychology DOI: 10.1002/acp.1644
Sunday, September 13, 2009
Saturday, September 12, 2009
Eye Movements Give Away Memories
September 10, 2009
Your eye movements can show that the elements of a memory are in place
even when you cannot consciously recall it or when you get it wrong, according
to a new study from the UC Davis Center for Neuroscience. The findings,
published Sept. 10 in the journal Neuron, could have several practical
applications.
It has been known for some time that a part of the brain called the
hippocampus is necessary for the conscious recall of memories, but Debbie
Hannula, a postdoctoral researcher at UC Davis, and Charan Ranganath,
associate professor of psychology, addressed the controversial question of
whether the hippocampus can support memories even when people are
unaware of them.
Hannula and Ranganath tracked the eye movements and scanned brain activity
of volunteers using a functional MRI (fMRI) machine while they performed a
simple memory test. The volunteers were briefly shown a scene, then a face
superimposed on the scene. To test their recall, they were shown the same
scene again, but with three faces on it, and asked which one they associated
with the scene.
Previous work conducted by Hannula and her colleagues had shown that the
eyes move to the correct face before the volunteer is aware of recalling the
memory. In the new experiments, the hippocampus lit up with activity seconds
before the eyes fixated on the correct face, even when participants failed to
explicitly recall it.
"The signal in the hippocampus was closely tied to how long people spent
looking at the right face," Ranganath said. “So even when your conscious
memory is wrong, the eyes (and the hippocampus) may have it.” Ranganath
said.
The fMRI images also showed more activity in another part of the brain, the
prefrontal cortex, when memories were correctly recalled. The scans showed
that communication between the hippocampus and the prefrontal cortex was
increased when people accurately recalled the face.
"We think that conscious memory comes from communication between the
hippocampus, prefrontal cortex, and other parts of the brain," Ranganath said.
"But the hippocampus may be able to support memories, even when you can't
recall them."
The eye-movement technique could have a range of uses. For example, it could
be used to look for evidence of memories in people who are unable or unwilling
to consciously recall them, to study hippocampal function in patients or young
children, and in studies aimed at developing new drugs to improve memory
function, Ranganath said.
9/12/09 8:52 AMUC Davis News & Information :: Printable news
Page 2 of 2http://www.news.ucdavis.edu/search/printable_news.lasso?id=9230&table=news
The work is funded by grants from the National Institutes of Health.
About UC Davis
For 100 years, UC Davis has engaged in teaching, research and public service
that matter to California and transform the world. Located close to the state
capital, UC Davis has 31,000 students, an annual research budget that exceeds
$500 million, a comprehensive health system and 13 specialized research
centers. The university offers interdisciplinary graduate study and more than
100 undergraduate majors in four colleges — Agricultural and Environmental
Sciences, Biological Sciences, Engineering, and Letters and Science — and
advanced degrees from six professional schools — Education, Law,
Management, Medicine, Veterinary Medicine and the Betty Irene Moore School
of Nursing.
Media contact(s):
• Charan Ranganath, Center for Neuroscience, (530) 757-8750, cranganath@ucdavis.edu
• Andy Fell, UC Davis News Service, (530) 752-4533, ahfell@ucdavis.edu
Return to the previous page
Current News | UC Davis in the News | Publications | Broadcast | Multimedia | Related News | News
Service Resources
Search/Archives | Facts & Figures | UC Davis Experts | Seminars/Events
Subscribe to:
Posts (Atom)
