In this series, I dig a little deeper into the meaning of psychological terms.
This week’s term: memory
Memory is highly complex. There are multiple different types of memory, and multiple areas of the brain that are involved. Memories not only need to be encoded in the first place, but they also need to be stored and then retrieved when needed in the future. Retrieval can involve either recognition (recognizing a stimulus when presented) or recall (spontaneously producing information). Recall may be easier in the same physical location where the learning occurred.
Explicit memory comes under conscious control, and includes semantic memory (general knowledge) and episodic memory (memories of events). Types of episodic memory include autobiographical memory (things related to the self), and flashbulb memories, which involve important events at a specific point in time.
Implicit memory is what’s humming along behind the scenes. Procedural memory is a type of implicit memory that allows us to go on autopilot with routine tasks, like brushing our teeth. With priming, retrieval of a task-associated memory speeds up after doing the task.
Short-term memory is limited to around 18 seconds. Experiments have found that when recalling numbers, such as a ten-digit phone number, it is easier to remember numbers in chunks of 3+3+4 digits rather than trying to remember the 10 digits as a single unit. When trying to recall a phone number we may repeat it to ourselves over and over in order for to hold it in working memory; this is referred to as a phonological loop.
Working memory is a type of short-term memory that holds material available for processing and manipulation. Working memory capacity is correlated with complex cognitive task performance, including reading comprehension and problem solving. Working memory function tends to decline in advanced age.
Another type of short-term memory is sensory memory, which holds sensory details from the massive amount of stimuli picked up by our senses for a very brief time, around one second.
Our long-term memory capacity is enormous. Sleep enhances memory encoding in long-term memory, and allows neural connections to be strengthened.
Different types of memory work occur in different areas of the brain. The prefrontal cortex and parietal lobe are involved in working memory, while the hippocampus is the major structure involved in long-term memory. The amygdala is involved in emotional memory, and plays a significant role in trauma memories.
Stress can interfere with working memory, memory encoding, and the functioning of the hippocampus. Intensely stressful events may be so intolerable to the mind that they are repressed from conscious awareness.
There are a broad range of illnesses that can affect memory. In Alzheimer’s Disease, protein plaques invade the brain. In traumatic brain injury, there may be physical damage to areas of the brain involved in memory. Bipolar disorder and major depressive disorder have both been associated with decreases in size of the hippocampus. Abnormalities in the hippocampus have also been associated with PTSD and anxiety disorders.
I’ve definitely noticed that depression has an effect on my memory. I do much better with recognition than I do with recall. Spontaneously trying to fish things out of the recesses of my memory can be problematic, but I know the information (at least some of it) is still in there, because it’ll sometimes pop up unannounced when I’m not looking for it. I’ve learned to make note of things quickly because I know my working memory isn’t going to hold onto it very long.
Is memory something that’s a problem for you? Do you have any tricks you use?
You can find the rest of the What Is series on my blog index.