Chapter 14
Memory
Memory is one of our greatest assets as
a survival tool. It is flexible and adaptable, allowing us to generalize one
skill into many others (e.g., learning piano can help us master other
instruments). It makes connections between different bits of information (e.g.,
a smell or song can trigger vivid memories from childhood). Memory can also
connect us to emotions (e.g., past joys or traumas). It can guide us toward
awaiting pleasures or steer us away from future misery. Memory is constructive.
It can supply us with the raw material we can assemble into new creations or a
vision of a future to seek or avoid.
But, of course, our memory is often
flawed. In the months and years that pass after an experience, our brain’s
housekeeping process drops details, leaving gaps that our imagination fills in
later. The more times we recall an event, the more we misremember details or
even remember things that never happened. The memory of your first kiss is a
memory of many past memories.
Memory tends to be biased. We tend to
remember information that confirms our beliefs (Confirmation bias) or remember
events in a way that boosts our ego - like your 300-foot home run in Little League.
Finally, memory is vulnerable to trauma
and disease. PTSD, concussions, amnesia and Alzheimer’s are just a few
examples.
For those neuroscience nerds amongst
us, here is a quick dip into some of our current understanding of memory: The Hippocampus
is critical for episodic (personal experiences) and spatial memory. The Prefrontal Cortex
supports working memory and the organization of memories. The Cerebellum
and Basal Ganglia assist in procedural memory (skills and habits). And
the Neocortex is where long-term memories are gradually integrated.
Memories shift from short-term to long-term storage through hippocampal-cortical
interactions. Sleep assists this process.
It appears that memories are encoded by
strengthening or weakening synaptic connections between neurons. After repeated
stimulation, synaptic strength can persist. Glutamate, acetylcholine, dopamine, and cortisol (a stress hormone) are neurotransmitters and hormones that play roles in memory. Emotion
significantly enhances consolidation. Research shows that emotionally arousing
events are remembered more vividly due to interactions between the amygdala and
hippocampus.
Now let’s pull back for a more generalized view of how it works.
A stimulus has our attention; at some level of consciousness, we accept it; our brain “chews” on it (i.e., compares it to prior memories), and we store it for future retrieval.
In short:
Attending -> Receiving ->
Processing -> Storing -> Retrieving.
Referring back to the Human Nature
Process, two of the most critical nodes of the model are Knowledge and Beliefs.
Where are they held? In memory, of course. And when I assert that “We know
almost nothing (with certainty), but we can believe almost anything (with
conviction),” I am not just indicting our information sources; I’m implicating
our memory. And just as there are different types of knowledge, so too there are different types of memory.
Here is one schema of categorization.
Sensory Memory:
It captures raw sensory input (like sights or sounds) and lasts for less than a
second. It feeds perception but doesn’t hold or encode information for learning
Short-Term or Working Memory:
It holds information briefly (seconds
to minutes) for immediate tasks like decision-making and conversing.
For example, somebody says something that reminds you of something, but before
you share it, another person speaks, and you forget what you were going to say.
That’s the temporal nature of short-term memory. The popular Working Memory
Model (1974) suggested that working memory is not a single passive “storage
box” but an active, multi-component system that temporarily holds and
manipulates information for thinking, learning, and reasoning. More recently,
even this model is viewed as too simplistic. Today, neuroscientists view the
process elements as: Distributed (involving prefrontal, parietal, and sensory
cortices), Dynamic (with items entering and exiting focus based on attention
and task demands), Integrated (interacting with perception, attention, and
long-term memory), and Context-dependent (where the type of task determines
which neural systems are engaged).
Long-Term Memory
Long-term
memory is the brain’s system for storing information over extended periods -
from hours to an entire lifetime. It allows us to remember our childhood home,
recite a poem learned decades ago, ride a bicycle without conscious effort, and
recognize the face of a close friend. Without long-term memory, identity itself
would fragment. While working memory holds a limited amount of information
briefly, long-term memory has a vast capacity and relative durability.
Once encoded and consolidated, information can persist for years.
Long-term memory is not a
single system but a collection of interacting systems:
Explicit
(Declarative) Memory is
conscious, reportable memory. It includes episodic memory (personal
experiences) and semantic memory (facts and general knowledge)
Implicit
(Nondeclarative) Memory is
unconscious memory expressed through action. It includes procedural skills
(such as riding a bike and typing) and habits.
Long-term memory is not merely storage - it is the narrative backbone of the self. Our remembered past informs our values, motivations, fears, and loyalties. Yet because memory is reconstructive, identity is partly interpretive. We live not only in what happened, but in how we remember what happened. Understanding long-term memory therefore contributes directly to cognitive bias, emotional regulation, moral learning, and personal growth.
Let’s now turn our attention
to the related topic of Knowledge.