Experiment Testing Iconic Memory

Laura Clarke

Memory Experiment 28/9/00

Introduction

There are 3 types of memory; iconic, echoic and semantic. I am going to do an experiment on iconic memory. This is the visual sensory store.

This type of memory has attracted most research. 1960 brought an experiment by Sperling. He conducted a series of experiments where he showed participants 3 rows of 4 letters for 50 milliseconds. He found that people could recall about 4 or 5 letters from the table but his participants reported the feeling that they had seen more than 4 or 5 letters but could not recall them. I can relate this to my experiment as Sperling used iconics as the base of his experiment as will I. I will use pictures and words instead of letters.

It is important to recognise that a normally functioning memory system must be able to register information, storing information over time and retrieving information when required.

Philosophers have been interested in memory for over 2000 years. It is in the last 50 years that psychologists have studied the topic. The topic is called “cognitive psychology”. It is the research field which focuses on the mental processes humans use to gain, store, retrieve and use their knowledge.

Aside of iconics, echoic and semantics there are 3 basic types of memory: sensory memory, short term memory and long term memory. I will be testing short term iconic memory.

Short term memory (STM) is a system for storing information for short periods of time, it can hold a few items at any one time. It has a brief duration. After this short period of time we forget these items. Mental arithmetic indicates that STM has a limited capacity. We can only hold a small number of items for a short period of time.

One way that many psychologists have tested STM is by measuring the immediate digit span. It is a technique which usually involves the participant to read out a list of random digits and being able to repeat them back in the correct order. The digits start out by being in a short sequence of about 3 digits and gradually building up until it is impossible for the participant to recall all of the digits in the corrects order. Most people have a digit span of 7 plus or minus 2 (Miller 1956)

More recently researchers have found that pronunciation time maybe an important indicator of STM capacity. Schweikert and Boruff(1986) tested immediate span for a number of different types of stimulus: eg, letters, colours, shapes and nonsense words. They found out that people constantly remembered as many items as they were able to pronounce in approx. 1.5 seconds. This experiment concluded that longer words are harder to recall that shorter ones because the participants said the words to themselves under their breath and longer words take linger to articulate.

When we forget, there are 4 main reasons why this ...

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When we forget, there are 4 main reasons why this happens: “displacement” is when items currently in STM are pushed out to make room for new items. The “decay theory” is when the memory traces fades away with time. “Interference theory” is when the memory traces are disrupted or obscured by other incoming information. The last is “retrieval failure” where items stored in Long-Term Memory cannot be accessed because suitable retrieval cues are not available.

Although the process of forgetting is relevant, I will not be investigating this topic in detail. I will, however, be investigating the difference in the rate people forget pictures as opposed to words.

My aim is to compose an experiment which is fair, ethical, scientific, and of use to me in my study of the human memory. I will be using well known psychiatrists experiments to give me help and ideas into my experiment.

My hypothesis is that the participants in my study will be able to remember more pictures that words. I think this is because they have more of a picture of the object when looking at the pictures, and also because as the participants try to remember each picture the will be able to see the object in their mind. They will be, in effect, remembering the item twice. Once to acknowledge the fact that they have seen the object and the second time to visualise the object in their mind.

The null hypothesis would be that there would be no difference between the words recalled and the number of pictures recalled. The results gained will be due entirely to chance.

This is a one tailed test. The results can only go in one way of the three different results it could result in.

Method

The method I will use will be quite simple. After giving each participant the brief , I will give them a sheet of paper with a list of 25 cement words. They will have 1 minute after which I will immediately give them a piece of paper and take away the list of the words(see appendix 1), and they will write all the words they can remember. They will have 1 minute to do this, after this time I will take away the sheet of paper and add up all the words they remembered and that were on the original list. Words that were not on the original list would not be counted. After I have taken the sheet away I will give them the de-brief. I will repeat this 9 more times. When I have gathered 10 results I will repeat the experiment again, on 10 new participants, but instead of giving them a list of words, I will give them a sheet of paper with pictures of these cement words on instead(see appendix 2). My dependant variable is the participants memory, how many things they remember. They independent variable is the objects in a form of either words or pictures. I will use the independent subject design/unrelated. This will make the results easy to compare, there will be no fatigue effect, no boredom effect and no practise effects. I will however need a lot of participants and the participants will vary. I will pick the participants using opportunity sample, they will be the first people who come along who will be willing to participate.

I will need a brief, de-brief, sheets of paper for the participants to write on, pens, the list of words and the list of pictures.

I will keep the 25 words the same. Different words will make the text unfair as different words may have specific meanings to different people making them be able to remember more words than they would have if they meant nothing to them. All the words will be cement words. I will keep the time they are allowed to look at the words and the time they are allowed to write them down. This will be 1 minute for looking at the list, and 1 minute for them to write all the words they can remember down. My sample will consist of 10 participants doing the words list, and 10 people doing the pictures list. They will all be between the ages of 16-17, and in year 12. They will be of mixed sexes too.

I will give all the participants the same brief and the same de-brief to make sure they all do exactly the same thing. This will make it a fair test.

My ethical conditions will be kept the same too. All the results will be treated the same. They will all be kept confidential and I will ask all participants for their consent that I can use their results in my experiments.

Results

My data was collected as separate pieces of information. Each candidate gave only one result for either the words test or picture test.

Fig 1⇧

Fig 1 is a table showing the results for the word and picture memory experiment. The results for the number of words remembered are on the left, and the results for the number of pictures remembered are on the right.

Fig 2 ⇧

Fig 2 shows that the average number of pictures remembered is greater than the number of words.

The total number of words remembered was 120 out of 250 which was 48% of the list. The total number of pictures remembered was 161which was 64.4%. The average number of words remembered is 12, the average number of pictures remembered is 16.1. The mode for the words remembered was 16, for pictures it was 15. The median words was 11.5 and for the pictures it was 15.5. (see appendix 3)

All of these results could be used at an advantage but I will use the average number as it is fair and simple to calculate. It is also the most common way of finding results.

Fig 1 & 2 show a distinct trend that suggests the memory’s ability to remember pictures is greater than the memory’s ability to remember words.

Discussion

When looking at my graph I saw that generally the number of pictures remembered was higher than the number of words remembered. When looking at both graph and table I strongly refute the null hypothesis. It clearly shows that the number of pictures remembered is higher than that of the words.

I think that the experiment went well. I had enough time to finish the experiment and didn’t have to rush gathering the results. I think that all the results were reliable as there were no single results that stuck out and looked out of place. All the results fitted the trend that pictures were easier to remember than the words.

The only thing I would change if I did this experiment again would to totally isolate the participants before I gave them the list of words and pictures as I felt that sometimes they were slightly distracted by noise and other people.

As I predicted in my hypothesis I found out that more items were remembered in the form of pictures than words.