Memory Manipulated After The Event

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Memories are delicate and can easily be changed after the event.

This is the seventh nomination for the top ten studies in psychology. After a look at Miller’s magical number seven, we return to memory but this time not to the information processing capacity of memory. Instead we examine the quality of our memories, in particular the ways in which memory can be changed after the event we are remembering. The work of Elizabeth Loftus has been extremely influential in this area as one of her early studies demonstrates.

First, a snippet of my personal history. I have a memory from when I was three years old of playing in a sandpit. I don’t remember much else about it other than this sandpit was outside the building in which I lived. For years I used to think this was my earliest memory, now I’m not so sure and here’s why.

A car crash

Like some of the best experiments, although Loftus and Palmer’s (1974) study was quite simple, its implications were profound. In the first of two experiments, 45 participants watched a film of a car accident. Nine of these were then asked this specific question: “About how fast were the cars going when they hit each other?”. The other four groups of nine were asked an almost identical question but with one important difference. Instead of the word hit, the words ‘smashed’, ‘collided’, bumped, and ‘contacted’ were used.

The participants who were asked the question using the word ‘smashed’ as opposed to ‘contacted’, estimated the cars were travelling, on average, almost 10mph faster. The other words were fanned out in between.

So, what is this telling us? Probably, that because people are not good at gauging the speed of a car, the cue comes from the experimenter. If the experimenter asks the question using the word ‘smashed’, the participant assumes it was going faster than if they say ‘contacted’.

“It’s in the follow-up study that things get interesting.”It’s in the follow-up study that things get interesting. The same experiment was repeated roughly as before, but with 150 participants. This time, however, participants filled out a questionnaire about the crash and were then asked to return in a week. As before, the question about the speed of the crash was varied between groups. Some read ‘hit’, some ‘smashed’ and so on.

One week later participants returned and were asked to fill out a questionnaire about the accident in which was hidden a crucial question: “Did you see any broken glass?”. As broken glass is indicative of a more serious accident, so greater speed, Loftus and Palmer expected the group in which the word ‘smashed’ had been used would be more likely to indicate there was broken glass. This was exactly what they found.

Malleable memories

Reporting their experiment Loftus and Palmer adopt a cautious tone as befits a journal article. For them it is a replication of a fact already known. That the phrasing of a question about an event can affect our memory for that event. For me, although the experiment is deceptively simple, it goes to the heart of how memories are constructed. It makes me wonder if that childhood sandpit in my mind’s eye is really something I can remember.

What about your childhood memories? What about your memory for last week? To what extent are things you remember happening a week ago affected by intervening events and people? The beauty of Loftus and Palmer’s experiment is it shows how important other people can be in shaping our own memories.

Whether or not my memory is real or a construction isn’t so important in the context of that sandpit, but what if I’m an eyewitness to a serious crime, called to testify in court? What if an adult ‘recovers’ a memory of being abused by their parents as a child? The answers to these questions have vital impacts on the lives of all those involved. Loftus’ later work has taken in both of these highly controversial questions, and more.

Still, my thoughts often return to this original study in more mundane, personal terms. Do I really remember that sandpit? I can see myself sitting there, playing, looking up past the building, into the sky. If that memory is false, can I ever really remember anything?

Image credit: Joel Bedford

About the author


Dr Jeremy Dean is a psychologist and the author of PsyBlog. His latest book is "Making Habits, Breaking Habits: How to Make Changes That Stick". You can follow PsyBlog by email, by RSS feed, on Twitter and Google+.

Published: 2 March 2007

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