The Science of Memory: Fun Facts about memory

8 fun facts introducing the science of memory

What did you eat for dinner one week ago? What is your name? Who are you? When answering these questions, we are always referring to our memory, where information is actively encoded, stored and retrieved in the brain. Without memory, people are unable to learn, build on past experiences or develop the skills they need, whether in the present or when thinking about the future. As memory plays such a vital role in human life, psychologists have been actively researching this area for decades.

1. Memory with meaning is better remembered.

Memories are better kept with semantic encoding, which involves elaborating on the meaning of the information. Elaborating on meaning creates stronger links in the brain and deepens the level of information processing, so the memory tends to be stronger and last longer.

!! Additionally, repeated rehearsing may aid the retention of information in memory.

2. Some memories only last for a fraction of a second.

Sensory memory holds information from our senses (e.g., eyes, ears, skin) for a very short time. It includes iconic memory (sight), echoic memory (hearing) and haptic memory (touch). Old information is quickly replaced by new information coming in, a process related to masking. Iconic memory lasts for less than a second; George Sperling’s classic 1960 experiments, which studied iconic (visual) memory, showed how quickly this visual trace fades. Echoic memory, for what a person has heard, can last a few seconds (around 3–4 seconds), and haptic memory, the brief memory of touch, is thought to last around 2 seconds.

3. Loss of vision may disrupt memory ability.

A loss of vision is associated with changes in the brain through synaptic plasticity, a process that enables experience-dependent adaptation, learning and memory. Researchers from Ruhr-University Bochum found that after the onset of blindness, there are changes in the density of neurotransmitter receptors that are crucial for synaptic plasticity. As synaptic plasticity in the hippocampus becomes more impaired, spatial memory may be affected in the following months (Ruhr-University Bochum, 2018).

4. The memory retrieved can be false.

A human mind can create, exaggerate, or re-invent a memory. In Loftus and Palmer’s experiment on the distortion of memory, participants watched videos of car accidents and then answered the question “How fast were the cars going when they smashed into each other?” For different groups, the word “smashed” was replaced with other verbs such as “collided”, “bumped”, “hit” or “contacted”. Participants estimated higher speeds when researchers used a harsher word in the question. In other words, the way a memory is “reactivated” can change what we remember.

5. Hot flashes impair memory performance.

Previous studies have shown that women going through menopause with vasomotor symptoms, including hot flashes, may experience a decline in memory for verbal material such as words and stories. Functional Magnetic Resonance Imaging (fMRI) studies suggest that physiological hot flashes are associated with poorer memory performance and changes in brain function, specifically in the hippocampus and prefrontal cortex.

6. Short-term memory can only hold a handful of items.

Our attention lets us focus on a small part of all the sensory input around us, and short-term memory can only hold a limited amount of it. In a famous 1956 paper, George Miller suggested that short-term memory holds about seven plus or minus two items, or “chunks”, of information. Newer research suggests the true capacity of working memory is smaller, about four chunks (Cowan, 2001). Information in short-term memory may be held for up to around 30 seconds, and longer if we keep rehearsing it.

7. Sleep deprivation may lead to memory loss

Sleep was first thought to help memory mainly by protecting memories from interfering stimuli. We now know that sleep also plays an active role in helping different types of memories undergo consolidation. Sleep is usually described in four stages: N1 (the lightest sleep), N2 (light sleep), N3 (deep sleep, also called slow-wave or delta sleep) and REM (rapid eye movement) sleep (Sleep Foundation, n.d.). Older textbooks split deep sleep into two stages, which is why you may still see five stages listed.

During slow-wave sleep (N3), declarative memory (memory that can be consciously recalled) is held in a temporary store in the hippocampus, then repeatedly reactivated and redistributed to long-term storage in the cortex. REM sleep, in contrast, has been linked with the consolidation of procedural memory: unconscious memory of skills and how to do or use things, as well as movement of the body. This is one reason why sleep deprivation is associated with poorer memory.

For a short explanation of how a good night’s sleep benefits memory, watch the TED-Ed video The benefits of a good night’s sleep (Shai Marcu).

8. Drawing is better than writing

Many studies have found that memory retention tends to decline in older adults, partly due to age-related shrinkage of the brain, which affects structures involved in memory such as the hippocampus. However, research by Melissa Meade and colleagues at the University of Waterloo found that drawing information helped people remember it better than writing it out, even if they were not good at drawing, and that this benefit was especially large in older adults (University of Waterloo, 2018). Meade also suggested that drawing could be explored as a therapeutic intervention to help people with dementia hold on to valuable episodic memories.

If you have noticed changes in your own memory or concentration that worry you, a psychological assessment can help clarify what is going on. Only a qualified professional can make a diagnosis.

References

• Brain Made Simple. (2019). Human memory – facts. Retrieved from brainmadesimple.com/human-memory-facts/
• Cowan, N. (2001). The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24(1), 87–114. https://doi.org/10.1017/S0140525X01003922
• McLeod, S. A. (2013, August 05). Stages of memory – encoding, storage and retrieval. Simply Psychology. https://www.simplypsychology.org/memory.html
• Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Psychological Review, 63(2), 81–97. https://doi.org/10.1037/h0043158
• Ruhr-University Bochum. (2018, December 19). How the brain reacts to loss of vision: Going blind affects all senses, and disrupts memory ability. ScienceDaily. www.sciencedaily.com/releases/2018/12/181219115622.htm
• Sleep Foundation. (n.d.). Stages of sleep. https://www.sleepfoundation.org/stages-of-sleep
• Sperling, G. (1960). The information available in brief visual presentations. Psychological Monographs: General and Applied, 74(11), 1–29. https://doi.org/10.1037/h0093759
• University of Waterloo. (2018, December 6). Drawing is better than writing for memory retention. ScienceDaily. www.sciencedaily.com/releases/2018/12/181206114724.htm

This article is for general education only and is not a substitute for professional assessment, diagnosis or treatment.

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