In light of research carried out by Baddeley, Thomson and Buchanan (1975), a study was carried out using a related design to investigate whether word length and articulatory suppression affects memory recall. The study used an opportunity sample of 32 participants, who were asked to recall words from four lists of twenty words (either short or long) either with or without articulatory suppression.
The hypothesis of the study predicted that participants will recall significantly more words than short words, participants will recall significantly more words in the ‘no suppression’ condition than the ‘suppression’ condition and that participants will recall significantly more short words in the ‘no suppression’ condition compared to the long words with ‘suppression’.
A two way ANOVA was carried out to analyse the results. The findings showed that participants recalled significantly more words with ‘no suppression’ than with ‘suppression’; that participants recalled significantly more short than long words and that participants recalled significantly more short words with ‘no suppression’ than long words with ‘suppression’. The findings support WLE and indicate that AS has a detrimental effect on memory recall.
The working memory (WM) was introduced by Salame and Baddeley (1982, cited in Pring and Walker, 1994). One component WM, the phonological loop (PL) consists of two components (cited in Baddeley, Garthercole & Papagno, 1998). One component, the phonological store, is a short-term store with auditory memory traces that are subject to rapid decay. The second component, the articulatory control system, allows for sub vocal rehearsal of the information stored in the phonological store, and can revive the memory traces.
Empirical support WM and in particular the PL stems from research into the effects of articulatory suppression (AS) and word length effect (WLE).
The present study investigates dual task logic that when a person tries to carry out two tasks simultaneously that use the same perceptual domain, performance is less efficient than when performing the tasks individually, (Simon and Sussman, 1987). This study focuses on the WM and the effects of AS and WLE on an immediate serial recall task.
WLE (Baddeley et al, 1975, cited in Cowan, 2005: 27) refers to the ability to reproduce a sequence of short words better than long words. This suggests that the capacity of the PL is determined by temporal duration and that memory span is determined by the rate of rehearsal. It is suggested that words with more syllables that take longer to speak, are more difficult to retain and recall than words with fewer or one syllable than can be more spoken rapidly (Berman, 2003).
Support for WLE stems from an investigation looking at the effect of word length on recall and on a recognition test in which the stimulus was presented auditorily, where output delay was controlled. The result of this investigation indicated that immediate serial recall for word sequences decreased systematically with the number of syllables within the words (Baddeley, Chincotta, Stafford & Turk, 2002).
AS involves the articulation of an irrelevant sound during the presentation of stimulus that is required to be retained and recalled. It is suggested that AS impairs recall as the irrelevant sound is assumed to block the articulatory rehearsal process, thereby the memory traces in the PL are left to decay, (Richardson and Baddeley, 1975).
Empirical support for the effects of AS stems from a study investigating the effects of articulatory suppression on a recall task. The results of the study indicated that AS reduces immediate serial recall substantially when taking part in memory recall tasks (Baddeley, 1990; Levy, 1971, cited in Coye, Divin & James, 2001). Conclusions of this study lead to the suggestion that suppression engages the capacity of the PL, thus disrupting rehearsal, therefore making the ability to retain and recall the information more difficult.
A study carried out by Baddeley, Thomson and Buchanan (1975) investigated the WLE and the effect of AS on immediate memory recall. There findings indicated that words with fewer syllables are recalled more effectively than words with numerous syllables. The results of this study indicated further that when participants were exposed to AS, recall was detrimentally affected.
This study partly replicates the research carried out by Baddeley, Thomson & Buchanan (1975) in order to validate their findings with regards to the WLE and the effects of AS. The study aims to investigate whether WM is involved in cognitive tasks, looking specifically at the effects of AS and the WLE on short-term memory. This leads to a one-tailed hypothesis that participants will recall significantly more words than short words, participants will recall significantly more words in the ‘no suppression’ condition than the ‘suppression’ condition and that participants will recall significantly more short words with ‘no suppression’ condition compared to the long words with ‘suppression’.
The current experiment used a related design. There were two independent variables. The first variable; the suppression of the words presented, was manipulated so that the words were presented with ‘suppression’ or ‘no suppression’. AS was created by asking participants to utter the word ‘the’ repeatedly while the word lists were presented to them. The second variable; the length of the words, was manipulated so that they were either ‘short’ (one syllable) or ‘long’ (numerous syllables). The dependant variable was the number of words recalled by the participants out of the four lists of 20 words.
An opportunity sample of students from a psychology class was used in the experiment. There were a total of 32 participants; a ratio of 5 males-27 females. Participants were aged between 19 and 50 years.
Participants were exposed to four lists of words. Each list contained twenty words which randomly generated by the experimenter and were presented to participants auditorily. (See Appendix One for the word list. Paper and pens were used by participants to recall words, and a stopwatch was used to time the task.c
The results of the study show that participants recalled significantly more words with ‘no suppression’ than with ‘suppression’ condition; that participants recalled significantly more short words than long words and that participants recalled significantly more short words with ‘no suppression’ than long words with ‘suppression’. This therefore supports our hypothesis that participants will recall significantly more short words than long words; participants will recall significantly more words with ‘no suppression’ than with ‘suppression’ and that participants will recall significantly more short words with ‘no suppression’ compared to long words with ‘suppression’.
The findings of the study support the suggestions of WM, indicating that in particular, the PL is involved in cognitive tasks. The results further support the dual task paradigm that the performance of two tasks that use the same perceptual domain is not as efficient as when the tasks are performed individually. This supports the suggestions that the PL struggles to process more than one phonetic stimulus at one time. In this case, the irrelevant sound that was uttered during the task was processed through the PL, therefore preventing the sub-vocal rehearsal of the words that were required to be recalled by participants.
The results of the study support the suggestions of AS and the WLE. The significant interaction found between the conditions ‘short words with no suppression’ and ‘long words with suppression’ indicate the detrimental effects that both AS and WLE have on memory recall.
The results of this study support the suggestions of Baddeley, Thomson and Buchanan (1975) that AS has a detrimental effect on recall and supports the suggestions of the WLE, that it is easier to recall short words than long words. However, the present study does not support the findings of Baddeley, Thomson and Buchanan that AS cancels out WLE. Future research investigating solely whether AS cancels out WLE may be beneficial for understanding the true effects of AS on memory recall, further establishing the role of the PL and its importance in short-term memory.
Further support for AS stems from the suggestion that AS has the same impact on recall if the stimulus presented visually or auditorily, as both require sub vocal rehearsal. A study by Murray (1968, cited in Osherson & Gleitman, 1995) indicated that when participants were required to recall a list of visually presented letter sequences during AS, performance was impaired. This therefore supports the suggestions of AS having a negative effect on sub vocal rehearsal, therefore leading to impaired memory recall.
The results of the study further support the suggestion of the WLE. It is suggested that the memory span within the PL is subject to rate of rehearsal. Therefore, the results indicate that words with fewer syllables are rehearsed more efficiently than words with numerous syllables and are therefore recalled more effectively.
The suggestions of WLE are supported by a study carried out by Neath and Suprenant (2005, cited in Lamberts and Goldstone, 2005) where their findings indicate that in a memory recall task, words that take longer to pronounce are more difficult to recall that words that can be pronounced more quickly.
However, the suggestions of both WLE and AS can be criticised for not taking into account how recall of certain words may be improved depending on how meaningful they are to each participant. It has been suggested that the more meaningful words are, the more easily there are recalled in memory tasks (cited in Higbee, 2001). This may therefore lead to individual differences, suggesting that the levels of recall may be partially affected by how meaningful the words are to participants. Future research, taking this into account, may be considered when investigating WLE and AS in order to observe these effects from an alternative angle.
The present study can be criticised however, for basing its criteria for ‘long words’ on the amount of syllables as opposed to pronunciation time. Future research taking this into account may offer an alternative angle to the investigation.
The present study can be additionally be criticised for not taking into account learning difficulties or hearing problems. Difficulties such as these may have impaired recall for certain participants. Future research taking this in account may provide more valid results.
Considering the findings of the study, it appears that WLE and AS both have negative effects on memory recall, supporting the suggestions of Baddeley, Thomson and Buchanan (1975), further validating the assumptions of WM and the PL being involved in cognitive tasks. However, future research taking into account past and current limitations may provide more accurate understanding of short-term memory and in particular the PL.