Dual task studies have found that Task 2 response information is activated during Task 1 response selection, and can have a priming effect on Task 1. This is called the backward compatibility effect (BCE). Giammarco et al. (2016) found that single-task practice of Task 2 in the context of a random, filler task (Practice-T2 condition) extinguished BCE development in a subsequent dual-task. On the other hand, practicing Task 2 in the context of Task 1 (Practice-Both condition) promoted BCE development in subsequent dual-tasks. Experiment 1a sought to replicate this context-specific disruption of BCE development by presenting participants with a single-task practice phase where they practiced Task 2 along with a filler task, and then observed BCE development in a subsequent dual-task phase. Experiment 1b addressed a counterbalancing issue in Experiment 1a. Experiment 2 was an exact replication of the Practice-T2 condition used in Giammarco et al. (2016). Overall, we conceptually replicated the context-specific disruption of BCE in Experiment 2, but not in Experiments 1a and 1b. Further study is warranted to determine the effect of specific response features on the learning context of Task 2. / Thesis / Master of Science (MSc) / Backward compatibility effects (BCEs) have been consistently observed in dual task paradigms. BCEs occur when Task 1 and Task 2 response information are congruent: participants respond faster to Task 1 when the two tasks require congruent responses than when they require incongruent ones. This suggests that there is some parallel processing of Task 2 while performing Task 1. The purpose of this study was to explore the episodic account of BCE development. Since episodic memories are context-specific, BCEs should also be context-specific, according to the episodic account. By manipulating the context of Task 2 learning, we tested whether this affected subsequent BCE development. Our findings suggest that context-specific disruption of BCE development is possible, but depends on other factors as well.

<p dir="ltr">The implementation of vibrotactile stimuli has grown in necessity where visual and auditory modalities are overloaded. However, how attention is oriented using vibrotactile information has been minimally investigated compared to other modalities, such as visual and auditory stimuli. The ability to elicit an appropriate mapping between a response from a specific vibrotactile stimulus can be explained in three different frames of reference accounts: internal, external, or remapping. Previous research has answered questions relating to the ability to use different reference frames but have yet to agree which frame orients attention for creating an automatic response. Using various stimulus-response mapping effects, the current study investigated how competing frames of reference are used to orient attention to select a response based on specific characteristics of vibrotactile stimuli. Experiment 1 validated the novel apparatus developed for this study by obtaining a stimulus-response compatibility effect. Experiment 2 investigated if an external or internal reference frame is used to orient attention automatically. The uncrossed-hands condition provided a replication of Experiment 1 and confirmed that a stimulus-response compatibility effect was present. For the crossed-hands condition, a diminished, reverse stimulus-response compatibility effect was present. Experiment 3 found no meaningful difference between a magnitude aligned (i.e., left associated with low frequency) versus misaligned (i.e., left associated with high frequency) conditions for frequency of vibrotactile stimuli, suggesting vibrotactile stimuli do not hold a mental magnitude line. Overall, the results from Experiments 1 and 2 provide evidence that processing of vibrotactile information is not reliant on only an internal reference frame but instead the external frame has some influence on selecting a motor response. Experiment 3 also suggests that task context influenced the stimulus and response mapping provided in the instructions, rather than the intrinsic, anatomical representation of vibrotactile stimuli.</p>

The joint Simon task is a cognitive reaction time task used to assess shared representations and self-other integration when performing a collaborative task with a partner. However, it is unclear if the underlying mechanisms are specific to representing spatial information or are more general. The objective of the current study was to assess a nonspatial joint Simon compatibility effect. Participants completed the joint Simon task with a partner while seated side-by-side, face-to-face, back-to-back, or with their partner not in the room. They completed the task three times, once with horizontal stimuli (left/right of center), once with vertical stimuli (above/below center), and once with central stimuli (at center). In the central task, compatibility was in color where participant responses (assigned red or green response buttons and gloves) were compatible or incompatible to the stimuli (colored red or green). Results showed no significant compatibility effect for any task in any response orientation condition, indicating no evidence of a nonspatial compatibility effect. Results even failed to replicate the standard joint Simon effect of a spatial compatibility effect in the horizontal task when seated side-by-side. However, exploratory analyses showed a significant nonspatial color compatibility effect in the central task for those assigned green in the side-by-side condition only, indicating that the presence of color in the participants' response (i.e., colored responses button and gloves) may have interfered with representing spatial information. This finding has implications for both theory and application of the joint Simon task, indicating it is sensitive to small changes, occurs for features besides location, and may be most effective when seated side-by-side. Additionally, the broader implications for the cognitive and practical study of joint action show the importance of how different features influence shared representations, how different colors are perceived and represented, and how different response orientations influence performance.

No description available.

A wide literature of predominantly behavioural experiments that use Stimulus Response Compatibility (SRC) have suggested that visual action information such as object affordance yields rapid and concurrent activation of visual and motor brain areas, but has rarely provided direct evidence for this proposition. This thesis examines some of the key claims from the affordance literature by applying electrophysiological measures to well established SRC procedures to determine the verities of the behavioural claims of rapid and automatic visuomotor activation evoked by viewing affording objects. The temporal sensitivity offered by the Lateralised Readiness Potential and by visual evoked potentials P1 and N1 made ideal candidates to assess the behavioural claims of rapid visuomotor activation by seen objects by examining the timecourse of neural activation elicited by viewing affording objects under various conditions. The experimental work in this thesis broadly confirms the claims of the behavioural literature however it also found a series of novel results that are not predicted by the behavioural literature due to limitations in reaction time measures. For example, while different classes of affordance have been shown to exert the same behavioural facilitation, electrophysiological measures reveal very different patterns of cortical activation for grip-type and lateralised affordances. These novel findings question the applicability of the label ‘visuomotor’ to grip-type affordance processing and suggest considerable revision to models of affordance. This thesis also offers a series of novel and surprising insights into the ability to dissociate afforded motor activity from behavioural output, into the relationship between affordance and early visual evoked potentials, and into affordance in the absence of the intention to act. Overall, this thesis provides detailed suggestions for considerable changes to current models of the neural activity underpinning object affordance.