In this series, I dig a little deeper into the meaning of psychological terms. This week’s term is memory.
Memory is highly complex. There are multiple different types, 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 is under conscious control. It includes semantic (general knowledge) and episodic (memories of events) memories. Episodic includes autobiographical (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 one type of this, and it allows us to go on autopilot with routine tasks, like brushing our teeth. With priming, retrieval of task-associated memories 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 to hold it in working memory; this is referred to as a phonological loop.
Working memory holds material in the short-term for processing and manipulation. Its capacity is correlated with complex cognitive task performance, including reading comprehension and problem-solving. Functioning tends to decline in advanced age.
Sensory memory is also short-term, and 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 encoding for long-term storage and allows neural connections to be strengthened.
Regions of the brain
Several different areas of the brain can be involved in managing particular types of memories. The prefrontal cortex and parietal lobe are involved in working memory, while the hippocampus is the major structure involved in creating long-term memories.
The amygdala is involved in emotional memory and plays a significant role in trauma memories.
Factors that can have an impact
Stress can interfere with working memory, the encoding of memories, and the functioning of the hippocampus. Intensely stressful events may be so intolerable to the mind that they are repressed from conscious awareness.
Effects of illness
There is a broad range of illnesses that can have an impact. 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 the formation and retention of memories.
Bipolar disorder and major depressive disorder have both been associated with decreases in the size of the hippocampus. Abnormalities in the hippocampus have also been associated with PTSD and anxiety disorders.
Living with depression
I’ve definitely noticed that depression has an effect on my ability to remember. I do much better with recognition than I do with recall. Spontaneously trying to fish things out of the recesses of my mind can be problematic, but I know the information (at least some of it) is still in there, as 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 brain 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 may also be interested in my review of Lisa Genova’s book Remember.
The Psychology Corner has an overview of terms covered in the What Is… series, along with a collection of scientifically validated psychological tests.