2nd
How walking through a doorway increases forgetting
“Like information in a book, unfolding events are stored in human memory in successive chapters or episodes. One consequence is that information in the current episode is easier to recall than information in a previous episode. An obvious question then is how the mind divides experience up into these discrete episodes? A new study led by Gabriel Radvansky shows that the simple act of walking through a doorway creates a new memory episode, thereby making it more difficult to recall information pertaining to an experience in the room that’s just been left behind. (…)
The key finding is that memory performance was poorer after travelling through an open doorway, compared with covering the same distance within the same room. “Walking through doorways serves as an event boundary, thereby initiating the updating of one’s event model [i.e. the creation of a new episode in memory]” the researchers said. (…)
Participants were more likely to make memory errors after they’d passed through a doorway than after they’d travelled the same distance in a single room.
Performance was worst of all when in the third, unfamiliar room, supporting the account based on new memory episodes being created on entering each new area.
These findings show how a physical feature of the environment can trigger a new memory episode. They concur with a study published earlier this year which focused on episode markers in memories for stories. Presented with a passage of narrative text, participants later found it more difficult to remember which sentence followed a target sentence, if the two were separated by an implied temporal boundary, such as “a while later …”. It’s as if information within a temporal episode was somehow bound together, whereas a memory divide was placed between information spanning two episodes.”
— Christian Jarrett, How walking through a doorway increases forgetting, BPS Research Digest, 2 November 2011
How is autobiographical memory divided into chapters?
“Autobiographical or ‘episodic’ memory describes our ability to recall past experiences and is distinct from semantic memory, which is our factual knowledge about the world. So far so good, but according to Youssef Ezzyat and Lila Davachi, psychology until now has largely neglected to investigate exactly how the brain organises the continuity of lived experience into a filing system of discrete episodes. (…)
Crucially, a minority of sentences began: ‘A while later …’, thereby conveying a temporal boundary in the narrative; the end of one episode and start of another. For comparison, a small number of control sentences began: ‘A moment later …’, indicating that the ensuing sentence was part of the same episode, not a new one.
After a ten minute break, the participants were given a surprise memory test. Presented with one sentence from the earlier narratives, their task was to recall the sentence that had followed. The key finding here was that the participants were poorer at recalling a sentence that came after a temporal boundary. It’s as if information within an episode was somehow bound together, whereas a memory divide was placed between information spanning two episodes.
A second study was similar to the first except that nineteen participants had their brains scanned during the initial read-through of the sentences. Ezzyat and Davachi identified patterns of neural activity in distinct regions of the prefrontal cortex and the middle-temporal gyrus that either correlated with within-event processing or with forming boundaries between events. These neural activity patterns were more distinct in those participants who showed larger behavioural effects of episode boundaries in their memory performance.
‘Our experiments are an important step toward understanding how event perception and segmentation influence the structure of long-term memory,’ the researchers concluded. ‘The behavioural results support the hypothesis that event segmentation shapes the organisation of long-term memory; the fMRI [brain scanning] results link these memory effects to brain activity consistent with information maintenance and integration within events.’”
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See also:
☞ G. A. Radvansky, S. A. Krawietz & A. K. Tamplin, Walking through doorways causes forgetting: Further explorations, The Quarterly Journal of Experimental Psychology, Volume 64, Issue 8, 2011
☞ Ezzyat, Y., and Davachi, L. What Constitutes an Episode in Episodic Memory?, Psychological Science, 2010
☞ How Does the Brain Retain Information? (infographic)
☞ Daniel Kahneman on the riddle of experience vs. memory
☞ Memory tag on Lapidarium notes
