Judging the words for whether they contain certain letters would be regarded as perpetual processing (as only the appearance of the words is important) and, in contrast to pleasantness rating, would be considered shallow processing.
So applying the principles of Craick and Lockhart’s theory, participants who have judged the words for pleasantness at encoding should recognise more words in the recognition task than participants who indicated whether the word contained and “E” of “G”.
Therefore the experimental hypothesis will be that more words will be recognised in the pleasantness consideration that the letters condition.
Method
Design
An independent groups design was used. The independent variable was the type of instruction given (i.e. whether to judge for “pleasantness” or “letters” condition). The dependent variable was the number of words successfully recognised by the participants.
Participants
The participants were first year under-graduate Psychology students following a course in basic cognitive functions at the University of Portsmouth. However, only the data from forty participants will be reported here, half of which were randomly assigned to the letters condition and the other half were assigned to the pleasantness condition.
Materials
The computer program ‘Erst Lab’ was used for this experiment. A thirty-item word list was also used.
Procedure
Half of the group were asked to judge the pleasantness of a series of words (responding pleasant or unpleasant) and then, in a subsequent recognition task, indicate ones they remembered seeing. This was called the “Pleasantness” condition.
The other half of the group saw the same list of words but they had to judge whether the word had either the letters “E” or “G” in it (responding yes or no). The second group also indicated which words they had seen before when they were exposed to a subsequent recognition task. This was called the “Letters” condition. Details of the actual instructions that were displayed on the computer screen are shown in Appendix A.
Appendix A:
Pleasantness condition
1) The initial set of instructions said:
This section of the experiment is a practice. Your first task is a judgement task. You will see a series of words. Your task is to judge whether the word is pleasant or unpleasant. If you think the word is pleasant you need to press the right shift key. If you think the word is unpleasant you need to press the left shift key.
Press space bar to begin
After seeing these instructions participants saw 10 individually presented stimuli. As each stimulus was presented a reminder of the response keys was also displayed (e.g. pleasant – press right shift key; unpleasant – press left shift key)
2) After this practice task the next set of instructions said:
The next stage of the practice is a recognition task. You will see pairs of words on the screen, one of which will have appeared in the judgement task. If you recognise the word on the left of the screen from the judgement task you will need to press the left shift key. If you recognise the word on the right of the screen you will need to press the right shift key
Press space bar to begin
After seeing these instructions participants saw 10 pairs of stimuli. Once again a reminder of the response keys was also displayed, though this time it was displayed under the relevant word (e.g. press shift left key under the left word and press shift right key under the right)
3) At this stage the practice had finished and the next set of instructions said:
You have just been exposed to a practice of the experimental task. From now on your responses contribute towards your experimental score. In the next section you will be exposed to a second judgement task. Your task is to judge whether the words are pleasant or unpleasant. You will need to press the appropriate key when you respond
Press space bar to begin
Participants were then exposed to 30 individual stimuli. Once again a reminder of the response keys was also displayed (e.g. pleasant - press right shift key; unpleasant – pres left shift key)
4) The last set of instructions that participants saw in the unpleasantness condition were:
The next stage is recognition task. Please follow the instructions on the screen and indicate (left or right shift key) whether you have seen the word during the judgement task
Press space bar to continue
After seeing these instructions participants saw 30 pairs of stimuli. Once again a reminder of the response keys was also displayed (e.g. press shift left key under the left word and press shift right key under the right).
Letters Condition
1) The initial set of instructions said:
This section of the experiment is a practice. Your first task is a judgement task. You will see a series of words. Your task is to judge whether the words contain an “E” or “G”. If you think the word contains and “E” or a “G” you need to press the right shift key. If not then you need to press the left shift key.
Press space bar to begin practice
After seeing these instructions participants saw 10 individually presented stimuli. As each stimulus was presented a reminder of the response keys was also displayed (e.g. word contains “E” or “G”: YES – press right shift key; NO – press left shift key)
2) The next set of instructions was exactly the same as the second set given to participants in the pleasantness condition (see item 2 in the pleasantness section above for details). The number of stimuli participants were exposed to was the same as well.
3) The next set of instructions said:
You have just been exposed to a practice of experimental task. From now on your response contribute towards your experimental score. In this next section you will be exposed to a second judgement task. As before you will see a series of words. Your task is to judge whether the words contain an “E” or “G”. You will need to press the appropriate key when you respond
Press space bar to begin experiment
Participants were then exposed to 30 individually presented stimuli. Once again a reminder of the response keys was also displayed (e.g. word contains an “E” or “G”: YES – press right shift key; NO – press left shift key)
- The final sets of instructions were exactly the same as the final set given to participants in the pleasantness condition (see item 4 in the pleasantness section above for details). The number of stimuli participants were exposed to was the same as well.
Results
Description
As can be seen from both the table and the graph, the number of words recognised in the Pleasantness condition was greater than the number of words recognised in the Letters condition.
Analysis
As there were two conditions (pleasantness vs. letters) and different participants were used in each condition, an unrelated t-test was used. See Appendix C for calculations
- A one tailed test was performed at a 5% significance level (p<0.05)
- The “degrees of freedom” was 38
- The calculation t-test i.e. t-value found was |-3.37| (to 2 dps)
Since this value was larger than the critical value the alternative hypothesis (H1) was accepted.
From this we can accept the alternative hypothesis and conclude that significantly more words were recognised in the Pleasantness condition than the Letters condition.
See Appendices for calculations and table of data.
Discussion:
There is clear evidence to show that more words were recognised in the pleasantness condition than the letters condition. Since rating words for pleasantness involved semantic processing, it can be said that the results of this study support Craick and Lockhart’s “Levels of Processing Theory”; deeper levels of analysis produce stronger memory traces than shallow levels of analysis and that the depth of processing of a word has a large effect on its memorability.
There have been many experiments suggesting that deep processing generates better recall. In one study research participants were told that the researchers were studying perception and speed of reaction and they were shown forty-eight words. As each word was presented, the participants were asked a question about it. For some words, they were asked about the physical appearance of the word; this should produce shallow encoding. For others, they were asked about the sound of the word; this should engender an intermediate level of encoding. For the remainder, they were asked about the meaning of the word; presumably this would lead to deep encoding. After the participants had gone through the entire list of words, they were given an unexpected task; they were asked to write down as many of the words as they could remember. The results were in line with the levels of processing theory. Words that called for the shallowest processing (typeface) were reached worst of all; words that required an intermediary level (sound) were recalled a little better; and words that demands the deepest level (meaning) were recalled best of all (Craick and Tulving, 1975). Other experiments have applied this approach to non-verbal stimuli, such as faces. Here too, instructions for deep processing seem to promote memory (Shapire and Penrod, 1986; Bloom and Mudd, 1991; Sporer, 1991; Reinitz, Morrissey and Demlo, 1994).
When reviewing the results for each participant (see appendix b), it was found that the number of words recognised (out of 30) were very high. In fact the means for both conditions were above 25. A reason for this could be because the participants were informed of the memory test and it was not a surprise so it could be possible that the participants realised that a task such as simply detecting the occurrence of the letters “E” and “G” in the word lists would not enable them to remember much and so may have processed the words more thoroughly.
Since the sample was of University students studying psychology, it was also possible that they anticipated a memory test and thus were more careful when recording their answers. This sample was not a true representation of the population as they were all of the same age group and at their learning peak. It would be better to get a sample of people with a wider age range; this may be an idea for a future experiment. Also in a future study, participants from a wider variety of vocations should be used as the psychology students had an advantage in that they were studying a course in Cognitive Psychology at the time and lectures content coincided with the experiment, thus making them aware that “memory” was part of the experiment.
In conclusion, this study has successfully proved that Craick and Lockhart’s (1972) “Levels of Processing Theory” is right in saying that semantic analysis of information at encoding when storing information to the long term memory produces (more substantial) memory (traces) than perceptual levels of processing.
References:
Craick, F.I.M. and Lockhart, R.S. (1972) Levels of processing: a framework for memory research. Journal for Verbal Learning and Verbal Behaviour, 11, 671-684.
Craick, F.I.M. and Tulving, E. (1975) Depth of processing and retention of words in episodic memory. Journal of Experimental Psychology: General. 104, 268-294.
Eysenck, M.W. & Keane M.T. (1995). Cognitive Psychology: A Student’s Handbook, Hove, UK: Lawrence – Erlbaum Associates.
Gleitman H, Fridlund A.J. & Reisberg D (1999) Psychology 5th Edition. New York: W.W. Norton & Company.
