Theoretical Implications

The evidence obtained from the current results do not support the strength model of self-regulation as outlined by Baumeister and colleagues (Baumeister, 2002; Baumeister & Vohs, 2007; Muraven & Baumeister, 2000). The strength model posits a global energy reserve powers all self-regulatory behaviour. Evidence for the reserve is derived from lower performance following on from an initial effortful task (i.e., the sequential-task paradigm). There are believed to be differences in self-regu-lation capacities, which can explain why some individuals appear to have greater self-control over their behaviour in real-world settings (Baumeister & Heatherton, 1996).

The findings from the current experiments found that accurate performance did decline over the course of a task thought to require self-regulation processing, the letter-crossing task, and that performance on this task was strongly related to execu-tive functioning tasks. On face value, this suggested that the letter-crossing task was employing similar processing to that under the executive functioning tasks, and this processing weakened with time. The letter-crossing accuracy scoring measure did produce the functional markers of depletion. Depletion effects should be observed in other scoring measures where, arguably, failures should occur more frequently if the self-regulatory resource is weakening. For which, no differences were observed in self-regulation failures (i.e., distractors) over the course of the self-regulation task.

This result suggests that accurate processing is affected over the task, but not

goal-failures. In other words, if the regulation capacity is weakened, failures of self-regulation should not change, but accurate processing should.

Despite the significant correlations between tasks, individual performance on the letter-crossing task did not predict performance on the outcome tasks as it was expected to, and importantly, depletion transfer effects were not apparent in the data set unless self-regulatory failures (i.e., distractor responses) were considered.

Wherein behavioural differences on the post-test through weaker repetition effects presented potential depletion transfer effects, but only on memory tasks where the in-volvement of self-regulation was not obvious (i.e., OSPAN and ISR) and not on tasks requiring some form of inhibition or suppression of a foil (i.e., Stroop, PI-ISR).

This suggested that while the letter-crossing accuracy measure presented as the best functional marker of depletion on the letter-crossing task and depicted the expected downward trend over time, the finding that this measure produced no depletion trans-fer effects lead to question whether this score was measuring depletion at all. Over-all, the current results strongly suggest that the letter-crossing task, whilst it has been argued to require self-regulatory processing, does not. An alternative account is of-fered, whereby cognitive processes can account for processing under the letter-cross-ing task, and possibly self-regulation processletter-cross-ing capacity.

Friedman and Miyake (2017) put forth the suggestion of a common EF factor, which is effectively the summation of an individual’s executive functioning

re-sources in that numerous executive functions (inhibition, updating, shifting, and so on) form this common EF factor. This is in line with the unity and diversity account of executive functions (Miyake et al., 2000), whereby each executive function over-laps with another and may employ lower cognitive processes, such as searching texts for e-vowel combinations. While letter-crossing accuracy was correlated across all of the executive functioning tasks, and was therefore considered to be closely related to the common EF factor, letter-crossing distractors were found to explain differences in performance on some memory outcome tasks (i.e., OSPAN and ISR, but not PI-ISR).

The result that letter-crossing accuracy was strongly correlated to the com-mon EF factor, but distractor susceptibility accounted for differences in updating and binding ability, led to the conclusion that the different letter-crossing measures were tapping into different components of higher order cognition. These findings do not necessarily account for a difference between the common EF factor and WMC. The

acceptance of the potential for a system containing both the common EF factor and WMC system, or the possibility that these two systems communicate with each other, or may be identical, may be controversial to some. Importantly, this thesis does not distinguish between the cognitive markers in these schools of thought. For simplicity in this thesis’ argument, the two systems will be considered as more or less the same system. Whereby, letter-crossing accuracy is shared with the common EF factor, and distractor processing is accounted for by memory processing in

WMC. The simplest model that can account for these results is goal-maintenance and conflict-resolution processing.

Friedman and Miyake (2007; 2008; 2017) refer to the common EF factor as the ability to maintain goals and bias-processing favouring goal-relevant behaviour.

This common EF factor, also known as goal-maintenance, is generated from all exec-utive functions, which are also arguably independent abilities in their own right.

Where individuals will have different capacities in the common EF factor, but also variance in capacities within the independent abilities forming this factor. While all executive functioning tasks require effective goal-maintenance, including simpler processing such as binding under short-term memory tasks, this function is more crit-ical under conditions of interference or distractors. Where insufficient processing to-wards goal-maintenance will result in goal-neglect (Friedman & Miyake, 2017). This is where conflict-resolution processes should alert cognitive systems about the malalignment of task goals. As a result, inhibition is commonly linked with goal-maintenance and ongoing processing of the task goal (Friedman et al., 2008; Fried-man & Miyake, 2017). This should have been reflected in the current results. Instead, only accurate letter-crossing processing was found to be related to tasks requiring in-hibition or suppression (i.e., Stroop and PI-ISR tasks), rather than the failures of con-flict-resolution processing. This suggested then that another system was responsible for conflict-resolution. While the results suggested a link between distractor suscepti-bility and memory processing on the outcome tasks, conflict-resolution is not thought to be undertaken by WM (Unsworth, Redick, Spillers, & Brewer, 2012). It is possi-ble then that executive attention is also critical to this high level of cognitive pro-cessing. Where failures in self-regulation, or momentary lapses in goal-maintenance and conflict-resolution processing, could be explained through diverted or insuffi-cient attention.

Engle (2018) argues that controlled attention is required for the maintenance and disengagement of information, if required. The updated account follows that WMC forms the maintenance of information such as goals under divergent thinking, whereas the old executive attention account followed that WMC was the ability to control attention in the face of distraction and interference conditions (Engle, 2018).

What has been previously termed by Muraven et al. (1998) as mental energy, crucial for sufficient self-regulation, may then refer to this control in effortful cognition.

Executive attention may then be involved in the common EF factor of goal-maintenance by directing an individuals’ attention away from goal-irrelevant stimuli and towards goal-relevant information and behaviour, which can then allow an invidual to achieve short- or long-term goals. Furthermore, executive attention may di-rect controlled processing towards critical cognitive features such as conflict-resolu-tion mechanisms that override incorrect responses in accordance with the standards being maintained. An individual’s WMC, as explained partly through updating abil-ity, could then dictate an individual’s susceptibility to disruptions in goal-mainte-nance. Updating ability, but not necessarily WMC, remains the best method in de-ducing susceptibility to conflict-resolution processing failures. This was evident in memory processing in the link found between the letter-crossing task and updating ability, as measured by the OSPAN task, and binding ability, as measured by the ISR task.

Although not cognitively demanding, the letter-crossing task arguably re-quires some component of executive cognition. The decline in performance over the letter-crossing task could be explained through a decline in executive attention to-wards effective goal-maintenance, and reduction in biased-processing toto-wards the goal, which may include conflict-resolution processing. Of which, differences in self-regulation failures could be assumed to reflect differences in these abilities. The find-ings can then be accounted for by a combination of executive attention, the common EF factor, and WMC. At this point in time, these systems are too difficult to theoreti-cally split. The conclusion that self-regulation may be a summation of cognitive abil-ities working as one system or multiple systems communicating with one another, then provides the simplest answer for the current findings.