Saturday, October 22, 2011

Computers Knowing How Humans are Remembering

Standing in the grocery store, trying to remember the shopping list left at home, our brains employ a variety of memory systems to assist in the recall process. Now researchers are finding that they can use computers to model these same memory systems humans use to remember an event.

When the brain is attempting to remember an event, it is retrieving from memory not just that single event, but also everything surrounding that event, the context. By studying the contexts applied in remembering, the computer models are able to replicate human data, according to the study published in Neuropsychologia in January 2012.

According to Ehren Newman, a memory researcher at Boston University, “Computational models provide a means to understand un-intuitive patterns in the data.” By better understanding human memory systems, there are hopes that researchers will be able to hone in on understanding specific aspects of memory.

One such aspect includes tracking changes in memory retrieval as our brains age. As we age, our ability to recall memories generally decreases, but with this computer model it may be possible to identify which memory systems are not being employed as they were in younger years. Looking at younger and older memory data for a patient allows researchers to compare what changes in brain activity create the memory deficiencies. Understanding and being able to predict typical memory decline may lead to being able to identify unusual decline and use that identification to predict potential memory-related illnesses.

In addition to using this understanding to see how our memory systems change over time, this information could be used to see how the recall process is different for schizophrenic or amnesic patients, and address the cognitive problems associated with those illnesses.

“Many researchers are looking at how the brain is organizing recall underlying the memory process,” says researcher Joshua McCluey, “But not many are looking at free recall with an fMRI.” By looking at blood flow to the brain, an fMRI makes it possible to look more closely at what the brain is doing and monitor neural activity, which leads to better results. Because the results found are for free recall, which is when a participant remembers items in no particular order, the data gathered is more complex and representative of human experience.

To better understand how memory works and hopes to apply this understanding to issues like memory loss, schizophrenia, and amnesia, researchers at Vanderbilt University are studying the brain both when an event occurs and when it retrieves that same event from memory. This data is then used to develop a computer model of human memory.

The researchers generated memories for each participant by having her read a list of 12 words and mentally decide whether the object would fit in a shoebox or mentally decide whether the object is alive for each item on the list. Making this judgment serves to help solidify the memory in the brain. Meanwhile, an fMRI machine scanned each participant’s brain to see how it stored those memories. Later each participant was asked to recall every item on the list to the best of her ability. Again, during this recall portion of the test, the brain was scanned to see how the memories were retrieved.

Patterns that were observed and modeled by the computer include recency effect, which shows memory preference for items at the end of the list, the items most recently read. They also found a contiguity pattern, where participants are more likely to remember the word appearing immediately around, especially after, the previously recalled word. When they applied all the different patterns they discovered to the computer model, they were able to see that the computer, with good accuracy, could replicate the way that the human brain remembers events.

While this computer model can duplicate human memory, it cannot serve as a substitute for human memory and won’t help you suddenly remember those grocery items you’ve forgotten to purchase. It may, however, serve as a way to better understand what goes into making and recalling memories as researchers try to wrap their minds around the brain and how it functions.  

No comments:

Post a Comment