The main aim of the current investigation was to look at the working memory architecture of the qualitative change detection task, using similar dual task methods to that of the quantitative change detection task from study 3. This was to discover whether both visual and verbal information types were being used during this task and to discover if a more multicomponent approach could be taken towards these tasks as proposed by Logie (2011), as opposed to the original visual specific approach (Baddeley, 2012).
The current investigation also aimed to change the visuospatial and verbal attention tasks which were used in study 4a so that they were seen as more task demanding for participants.
Instead of showing 3 bars per trial or 3 numbers per trial, this was increased to 4 to eliminate the ceiling effect present in study 4a. There were 2 predictions regarding this study, stating that 1) the verbal interference task would have an effect on the primary task and 2) the visuospatial interference task would have a greater effect upon the change detection task indicating the greater use of visual representations. Results have supported prediction 1 but not prediction 2 as results demonstrated verbal interference but no visuospatial interference effects.
130 The effect of verbal interference in the current qualitative change detection task gives support to the previous literature from Brown and Wesley (2013) and also Hamilton et al. (2003).
Here, researchers demonstrated a more multicomponent approach to working memory architecture with interference effects from executive interference procedures such as random tapping.
Brown and Wesley (2013) produced results which indicated that a VPT can indeed use verbal representations, and the current study provided evidence for this using a qualitative stimuli paradigm. The findings of Brown and Wesley (2013) have been extended by the current results showing that a qualitative change detection task may also use domain general resources. Although Brown and Wesley (2013) and the current study used different methods in regards to the different interference procedures used, the evidence provided can still support the theoretical implications which implicate a more multicomponent approach (Logie, 2011).
The current results have contrasted the visual specific research from Luck and Vogel (1997, 2013). Luck and Vogel (2013) had proposed in their research review that visual working memory tasks should use visual material only and stated that if a visual memory task uses any type of other (verbal, amodal) representation then this task could not be seen as a visual working memory task. The current investigation has opposed the view of Luck and Vogel (2013) by providing evidence for the effect of verbal interference, suggesting the use of verbal information in a visual task as well as potentially visual information.
The findings that the Bar Fit task had no effect upon the qualitative stimuli has contradicted that of Vergauwe et al. (2009) who initially used the Bar Fit task to demonstrate that a visual matrix task could use visual and spatial elements. Vergauwe et al. (2009) used a maintenance interval of 8500ms which was more than double of the current study. It could be suggested that the longer maintenance interval may contribute to the decline in memory as well as the
131 visual interference paradigm. In the preliminary study by Vergauwe et al. (2009) several data sets were not used in the analysis as they did not approach the 80% performance level suggested for maximum task demands. This was a similar case with the current thesis for study 3 and 4b. Current researchers chose a 70-90% performance level interval and any data which did not meet this criterion was excluded from the analysis to ensure that the interference tasks were demanding enough as Vergauwe et al. (2009) suggested. This reduced great variability within the data sets and ensured that each task used the appropriate level of difficulty.
The interference of the Verbal Parity task in the current investigation has provided support for the suggestion that this task can interference with any form of task (Lépine et al., 2005).
Lépine et al. (2005) proposed that a verbal task may affect any form of other task, based upon the fact that it causes a divide in attention between the primary and secondary task. It was suggested that a distraction in attention from the primary task was enough to cause effects upon a primary task as interference effects were concerned with a person’s attentional control ability and not the fact that the secondary task was supposed to hit a specific working memory component.
Conclusions can be made suggesting that a more multicomponent approach could be used to discuss the working memory architecture during qualitative working memory tasks (Logie, 2011). The interference from the verbal interference task demonstrated the use of verbal representations, or potentially an executive resource function (Brown & Wesley, 2013) that could integrate both visual and verbal information in memory.
One question remains regarding the effects of the verbal interference. Although these interference types were seen to have an effect upon the qualitative change detection task, it is
132 unclear as to where these interferences are hitting. As the qualitative task used both smaller 5-10% changes and larger 15-20% changes, it raises questions as to where exactly this interference was hitting. In the next section, further analyses will now be conducted to look at the specific location of the interference types.