Extra Features

As well as the five Working Memory tests themselves, several other features were included in the application in order to improve its versatility. This section examines these extra features and what each one adds to the application.

As has been previously mentioned, one of the details recorded by the VAM application during the Working Memory tests was the candidate’s response time. Initially the purpose of this was to separate the time the candidate spent processing the information from the time they spent re-entering the sequences in each test. As an offshoot of this, several reaction time tests were included as part of the VAM. These included a simple stimulus/respond reaction test, a ‘do’ or ‘do not’ respond reaction test and a respond differently to different stimuli reaction test. Although detailed information was gathered on each candidate's reaction times, early testing showed there were too many variables involved to apply this data directly to a candidate's response time in the Working Memory tests. As such, the usefulness of

the reaction tests has somewhat fallen by the wayside. They are still included as part of the VAM application though in case they can prove useful in some other role. The design and layout of the reaction tests themselves are discussed in more detail in Appendix A.

One of the primary goals of the VAM application is to explore and record data on various different aspects of Working Memory. A large amount of data is gathered over the course of the VAM. All five tests record the stimulus sequence, the

candidate response sequence, whether the candidate is correct and the time it takes for him/her to respond to each individual sequence in each test. At the end of each test the VAM application uses these results to calculate further information including the average time taken per sequence and the percentage of sequences answered correctly by the candidate. This information is then formatted into readable result files and stored safely for further analysis.

As well as the data described above, the candidate is also required to enter other relevant information before beginning the tests. When the candidate first logs in to the system, he/she is asked to input his/her name, age, gender, occupation and whether he/she has previously used the application. This information is recorded so that future studies can explore the differences in Working Memory capacity with reference to factors such as gender or age.

The application stores three separate copies of the results file that are created for each candidate. One set of results is stored in a location preselected by the administrator so that all of the records can be kept together or at least in a common location on each machine. Another copy is stored in a more public location, the same folder the application is stored in. This is so that each candidate can have access to his/her results and can see how he/she fared in the tests without risking damaging the backup copies. Finally, as well as two text based versions of the results file, a more spreadsheet friendly summary of the results is saved as a .csv or comma spaced values file. When opened in Microsoft Excel or similar spreadsheet packages, the

statistics packages. This saves much time and effort during the analysis phase and is one of the many benefits that computerised tests of Working Memory have over using traditional paper based methods.

Another benefit of computer based tests of Working Memory is the flexibility and level of configurability they allow. In this case, an administration level was built into the application to allow administrators to configure various aspects of the

application.

The administration level of the application has four main set-up options. The first option allows the administrator to specify the storage location of the backup copy of the candidate’s results. This was included so that the candidate can view his/her results without risking him/her altering or damaging the originals. If the

administrator does not wish an additional copy of the results to be stored, this option can be turned off. When initially activated, the default storage location of “C:\” is used.

The second menu option contains the settings for the Working Memory tests and allows the administrator to change both the number of rounds used in each test as well as the number of trials given per round. The number of rounds refers to the maximum sequence length; each new round increases the maximum length by one. The number of trials refers to the number of sequences presented at each sequence length.

The trials menu also allows the option of staggering the round structure so that there are fewer trials in the early rounds and more in the later rounds. When the

administrator opts for this staggered round option, the candidate is only presented with two sequences if the length of the sequence is fewer than four, but is presented with five sequences to re-enter if the length of the sequence is four or over. By default, this option is turned off.

change whether the candidate needs to re-enter the sequence in forward or reverse order. The reverse order option is the default setting. This option can be useful in studies that differentiate between the storage aspect of audio and visual Working Memory and the information processing aspect. It should be noted that since the reverse option loads more heavily on a candidate's Working Memory, it is advisable to set the maximum sequence length used in each test accordingly.

The memory test options also allow the administrator to change the display time of the visual stimuli used in the memory tests. Some people may find a quicker presentation easier to remember, while others may prefer more time to digest the information they are seeing or hearing. By allowing the administrator to alter the display time, the test could be used to investigate not only the capacity of Working Memory but the storage length as well.

The third option on the main menu allows the administrator to alter the settings of the reaction tests that are not used in this study.

The final option on the main menu allows the administrator to change the password needed to enter the set-up menu. The default password of ‘ADMIN’ is already in place, but by using this option, the administrator can alter it to something they can remember more easily. When the administrators menu is exited, all of these settings are saved to a set-up file in the same folder as the program and so only need to be set- up once before using the VAM application in a particular study.

The default values for the configurable variables in the VAM application are as follows: The default number of rounds (which is also the maximum sequence length) is set to six. The number of trials per round is set to four. The display time for the visual stimuli is set to three quarters of a second.

These default values were chosen through a combination of examining current testing methods and conducting some initial pre-tests on the VAM. The maximum sequence length was set at six based on previous studies into digit span. As

described in Chapter 3, the average digit span of native English speakers tends to be about seven digits long. In this case, digit span refers to the number of digits that can be presented as a sequence and correctly recalled by a test subject. Many Working Memory test batteries that make use of digit span tests, such as Wechsler’s Memory Scales, set the maximum number of rounds at eight. This means the longest digit sequence will be eight items long. Because the stimuli types used in the VAM are more complicated than simple digits and because in the case of the VAM, the sequence needs to be reversed by the test subject before they re-enter it, it was felt a sequence of eight items might be too complicated for test subjects to reverse and recall. Initial pre-testing showed this deduction to be accurate and that a sequence of six items provided a challenge without being too difficult and disheartening to the average candidate tested.

Similarly initial testing showed that four trials per sequence length, as used in

Riding’s IPI, allowed detailed data to be gathered on candidate performance while

still allowing the tests to be completed in a relatively short amount of time. Using the above settings, candidates took, on average, twenty-five minutes to complete the VAM application. The more trials that were included per round, the longer the VAM took and the more subjects were likely to complain of test fatigue.

The visual stimulus display time of three-quarters of a second was chosen because initial tests showed that subjects felt most comfortable with this presentation time, with stimulus not being presented too fast, or too slowly. It should be noted

however, that although these values are used as the default settings by the VAM, it is recommended that administrators use their own judgement and if possible, some form of preliminary testing before choosing what values will be applied to the VAM in their own particular studies.

A complete, usable version of the VAM application can be found on the CD attached to the back cover of this thesis. This version contains a copy of the VAM application containing all five tests; the visual memory test with letters, the visual memory test with images, the audio memory test with letters, the audio memory test with images

and the audio/visual memory test with letters. This version of the VAM also contains all the extra features that have been discussed in the preceding sections including the reaction time tests. For further information on how to setup and run the VAM application contained on the CD, please refer to Appendix B.