Cognitive Neuroscience of Memory

The title of this post is the same as the title of an important book by Scott D. Slotnick. He writes in the preface, “The human brain and memory are two of the most complex and fascinating systems in existence. Within the last two decades, the cognitive neuroscience of memory has begun to thrive with the advent of techniques that can non-invasively measure human brain activity with spatial resolution and high temporal resolution.

Cognitive neuroscience had not been created when HM was a graduate student. The field is quite new. In cognitive psychology we studied cognitive processes, of which memory was central, but little was known about the neuroscience underlying memory.

Before getting into neuroscience it is important to understand what memory encompasses. Most people think of memory as something they need to use to pass exams, are frustrated by exam failures, and by an inability to remember names. Readers should be aware of the function of memory. Memory is a tool for time travel. We use it to help us predict and deal with the future. The more we learn, the more we have information for dealing with the future. Moreover, there are many types of memory.

The first pair of memory types is explicit memory and implicit memory. These refer to conscious memory and nonconscious memory. They differ in that all forms of explicit memory are associated with conscious experience/awareness of previously experienced memory, whereas all forms of implicit memory are associated with a lack of conscious experience/awareness of the previously experienced information.

Skills are one type of implicit of memory. After a skill is learned, performance of that skill reflects nonconscious memory. Once a person has learned to ride a bike, she doesn’t think about rotating the pedals, steering, breaking, or balancing. Rather, their conscious experience is dominated by where she wants to ride or whatever else she happens to be thinking about. Repetition priming is another type of implicit memory that refers to more efficient or fluent processing of an item when it is repeated. When a television commercial is repeated, that information is processed more efficiently (and when the item from the commercial is seen again while shopping, implicit memory presumably increases the chance that it will be purchased.) Skill learning can be assumed to be based on repetition priming.

The remaining memory types are types of explicit memory. A second pair of memory types is long-term memory and working memory. Working-memory is often referred to as short-term memory. A recognition memory experiment will be described to help make the distinction between long-term memory and working memory. During the study phase of both long-term memory and working memory, items such as words or objects are presented. After the study phase, there is a delay period that will last as a function of specific amount(s) of time. During the test phase, old items from the study phase and new items are presented, and participants make “old” or “new” judgments for each item. This is termed old-new recognition. A greater proportion of “old” responses to old items than “old” responses to new items indicates the degree of accuracy of the memories.

Long-term memory and working memory differ with regard to whether or not information is kept in mind during the delay period. Typically there are many items in the study phase and the delay period is relatively long (typically minutes to hours). Obviously participants do not actively maintain information from the study phase during the delay period. In working memory experiments, there are typically a few items in the study phase, the delay period is in seconds and participants are instructed to actively maintain information from the study phase in their mind.

Another pair of memory types is episodic memory and semantic memory. Episodic memory consists of the memories we have of our experiences. Semantic memory refers to retrieval of, hopefully, factual memory that is learned over periods of time such as the definition of a word. Unfortunately, semantic memory also consists of misinformation and erroneous beliefs. And, unfortunately, this misinformation and erroneous beliefs can be further amplified via technology and social media.

Another pair of memory types is “remembering” and “knowing.” “Remembering” refers to the subjective mental experience of retrieving details from the previous experience, such as someone retrieving where they parked their car in a parking lot. If any details are recalled from a previous experience, this constitutes “remembering.” “Knowing” is defined by the lack of memory for details from a pervious experience, such as when someone is confident they have seen someone before but not where or when they saw them. Remembering is usually assumed to be related to context memory, as it is thought to occur whenever contextual information is retrieved. “Knowing” is typically assumed to be related to item memory and semantic memory. The last pair of memory types is recollection and familiarity. The terms recollection and familiarity can refer to mathematical models of these two kinds of memory, but more commonly refer to all the forms of detailed memory (episodic memory, context memory and “remembering”) and non-detailed memory (semantic memory, item memory, and knowing). Dr. Slotnick writes, “It may be useful to think of context memory and item memory as measures of task performance, “remembering” and “knowing” as measures of subjective experience, and recollection and familiarity as general terms that describe strong memory and weak memory, respectively.”

Tags: , , , , , , , , , , ,

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: