Memory in humans works most like which of the following?

A: A video recording that plays back exactly what happened

B: A reconstruction that can be influenced and distorted each time we remember

C: A permanent filing system that never loses information

D: A random storage system with no organisation

Correct: A reconstruction that can be influenced and distorted each time we remember

Memory is reconstructive, not reproductive. Each time we recall something, we rebuild the memory using fragments of what actually happened combined with our current knowledge, expectations, and emotions. This is why memories can change over time, why details get added that weren't there, and why two people can have very different memories of the same event. It's a feature, not a bug — but it does make memory less reliable than we tend to assume.

It is possible to have a vivid, detailed memory of something that never actually happened.

Answer: True

Research by Elizabeth Loftus and others has demonstrated that false memories can be implanted — people can be led to "remember" events that never occurred in convincing detail, simply through suggestion. In one study, participants were convinced they had been lost in a shopping mall as a child, an event their families confirmed had never happened. This has important implications for eyewitness testimony and therapy.

What is the difference between short-term and long-term memory?

A: Short-term memory is for happy events; long-term memory is for traumatic ones

B: Short-term memory holds a small amount of information briefly; long-term memory stores information for much longer periods

C: Short-term memory is in the left brain; long-term memory is in the right brain

D: There is no real difference — they are the same system

Correct: Short-term memory holds a small amount of information briefly; long-term memory stores information for much longer periods

Short-term (or working) memory holds a limited amount of information — roughly 7 items — for a short period (seconds to a minute). Long-term memory is a much larger, more durable store. Information moves from short-term to long-term memory through a process called consolidation, which is strengthened by repetition, emotion, and sleep. The distinction was famously demonstrated by patients like H.M., who lost the ability to form new long-term memories after brain surgery.

Why is sleep important for memory?

A: Sleep gives the brain a rest, which prevents overloading

B: During sleep, the brain consolidates and strengthens memories formed during the day

C: Sleep has no proven effect on memory

D: Sleep clears all short-term memories to make room for new ones

Correct: During sleep, the brain consolidates and strengthens memories formed during the day

Sleep is not just rest — it's an active process of memory consolidation. During sleep, particularly during slow-wave and REM sleep, the brain replays experiences from the day, strengthening important connections and clearing out less relevant information. Studies consistently show that people who sleep after learning retain significantly more than those who stay awake. This is why "pulling an all-nighter" before an exam tends to backfire.

Forgetting is a sign of a weak or damaged memory system.

Answer: False

Forgetting is not a flaw — it's a feature. The brain actively filters and discards information that isn't deemed important, which prevents cognitive overload and makes it easier to access the information that matters. In fact, the rare condition known as hyperthymesia — where people remember virtually every detail of their life — is associated with difficulties functioning normally, suggesting that selective forgetting is essential to healthy cognition.

Eyewitness testimony in criminal trials is:

A: Highly reliable because people remember emotionally significant events very accurately

B: The most reliable form of evidence available to courts

C: Often unreliable, as memory can be distorted by stress, suggestion, and the passage of time

D: Only unreliable in elderly witnesses

Correct: Often unreliable, as memory can be distorted by stress, suggestion, and the passage of time

Decades of psychological research show that eyewitness testimony — while persuasive to juries — is one of the least reliable forms of evidence. Stress impairs detailed encoding, leading questions from police or lawyers can alter memories, and confidence does not predict accuracy. Studies of wrongful convictions in the US have found that mistaken eyewitness identification was a contributing factor in over 70% of cases later overturned by DNA evidence.