Non-flash index. Recent Horizons. Pick of the archive. Web exclusives. Programme summary. Horizon journeys into the human memory, from how it emerges in childhood, develops through to adulthood, and fades in middle age.
Memory and the senses. Martin Conway reveals how our personal memories are linked to our senses. Can we implant a false memory in you? Professor Dan Schacter has designed a test to illustrate how easily our memory can deceive us. Would you have your memory wiped? A pioneering technique may help to actually forget some events in our lives - simply by taking a pill. Ok that's the end of the list. Now if you have a few seconds, what you might do now is just simply try to remember all the words from the list on your own that you can.
Jot them down there were 15 words should just take you a little bit of time to remember as many words from that list as you can. Now I'll give you a recognition test. I'll say a word and think to yourself was that word on the list, or was it not? If you think it was on the list write down yes and if you don't think it was on the list write down no. You can also indicate how sure you are in your judgement, are you sure it was on the list? Or not on the list or are you not sure?
So the first word is taste, was that one of the words I said just a few minutes ago? Yes it was, no if it wasn't, sure or not sure. The second word is point. Was that one of the words that I just said on the list? Yes if it was, no if it wasn't. Are you sure, or not sure about your judgement?
The next word is sweet is that one of the words I just said on the list? Sure or not sure? That's the end of the test. And what you may find is that if you're like most people you think you think that the first word taste was on the list.
If so very good, pat yourself on the back you got it right it was there. The second word point you probably thought wasn't on the list and indeed it wasn't. The interesting case is the third word, sweet, did you think that one was on the list? Most people think it was and they're very sure that it was in fact it was not. That was not one of the words I said but if you go back to the list, what you'll find is that it's related to all the words I said.
Candy, sour, sugar, bitter, good, taste, tooth, nice, honey, soda, chocolate, heart, cake, eat, pie. Sweet wasn't there but all those words are related to sweet.
So if you thought that sweet was on the list, the reason you did that is that er your memory is kind of recapturing the general gist of what I said.
So for example you might present someone with the word oranges and ask them to recall a memory. On the other hand we might present them with a picture of oranges and ask them to recall a memory or finally we might take a real orange, squash it up, extract its smell and put it in a test tube and present them with the smell of an orange in a test tube and ask them to recall a memory. And that's one way to test these differences in recall to different cues and what we'd be interested in there is how different peoples memories were how emotional they were, and crucially what part in their life the memory dated to.
Visual cues and word cues that are used in these sorts of experiments have found that people over the age of around 35 years of age tend to recall an unexpected amount of memories that date to when they are between 15 and 25 years of age. We get a graph that looks something like this. This period is known as the period of the reminiscence bump.
Which is a strange name, but it simply means that people seem to be able to access more memories from this period. They have a bias to access memories from this period.
And of course the question is why? Well, one fairly obvious explanation why is that lots of novel things happen in that period it's a kind of novelty effect.
But in fact if that were true we'd effect far better recall from these early periods of childhood when things are much more novel, so novelty doesn't actually work as an explanation of the bump. Another explanation is to do with maturation of the brain we now know that the brain goes through a period of development in late adolescence, early adulthood and probably what's happening is that it's increasing its efficiency it just might be the case and we don't know if this is true or not yet, but it just might be the case that the brain is simply working more efficiently in that period.
And so there's some special encoding that makes it especially available throughout the rest of one's life.
Another account and this isn't necessarily excluding the brain maturation hypothesis is that the events that occur at this time relate to a special period in development of the self. A period in late adolescence, early adulthood that the self finally coalesces, it comes out of childhood becomes a stable mental representation and will remain that way pretty much for the rest of our lives and what's important here is the events that are encoded are encoded because they represent enduring themes throughout out life.
Those themes may not be that self evident to the individual, who knows you might need a therapist to point them out but none the less they are there. Certain cues are more likely to take you back to early childhood memories than others.
We explore the role of smell in our memories. When the memories are cued by smells rather than in some other way, the distribution is really very similar, except that the bump now occurs earlier. And that just reflects that fact that when people recall memories to smells they tend on average to get earlier memories. Memories that date to when they were ten years or younger. Usually with a mean of around about eight years. And the question of course is why?
And again there are several different explanations. One might relate to the brain, we know that the neural pathways from smell from the nose into the memory areas of the brain is much more direct than it is for other routes which have to go through other processing areas.
So there might be something about smells getting into the memory system in a privileged sort of way that has some sort of advantage and perhaps it's that that gets you to those earlier memories. We don't know. Another possibility is that smells are rather unique, they're much more specific than other types of cues, there might be that specificity that gets them in there and gets you to on average and earlier memory.
There are other possibilities too it might be that a child perhaps is much more sensitive to smell than an adult or an older child, a young child, and it may be that their memories are more likely to be coded up with smell in them.
Certainly is the case with adults that their memories appear to be largely visual in nature. So it may be that those early memories actually have smell information in them so when you encounter a cue it's a very potent cue for getting into those early memories. Woman: That's quite a strong smell, it reminds me of tar or bitumen or something they put on the roads and as soon as I smelled that it took me back to when I was about 10 or 11 living with my mum and my brother and I was a big fan of Donny Osmond at the time and I remember getting my finger and putting it in the wet tar on the side of the road where they'd been working and writing the initials DO on a green gate.
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