Attended information is perceived quicker than unattended information. This is known as prior entry. When making judgments on the temporal order of two successive stimuli, performance is influenced based on attention. We were interested in whether this same attentional shift would occur when we adopt a crossed hands posture. Typically when making these tactile temporal order judgments, performance declines when the hands are crossed. This may be due to a greater influence of the external environment in the crossed posture. We investigated this by providing an exogenous visual cue at one or both of the hands prior to making judgments about the temporal order of two successive vibrations. This was completed with the hands crossed and uncrossed. In Experiment 1 responses were to which stimulus occurred first. In Experiment 2 participants responded to which stimulus occurred second. Changing the response requirement did not influence overall performance. In both experiments we observed prior entry that was in the same direction for both crossed and uncrossed postures. The size of the prior entry effect was larger when the hands were crossed. We remap tactile information quickly to external coordinates, however we are less certain of the hand’s location. / Thesis / Master of Science (MSc)

Prior entry refers to the notion that attended stimuli are perceived sooner than unattended stimuli due to a speed up in sensory processing. The century long debate regarding the prior entry phenomenon’s existence has always been grounded in the degree to which the methods applied to the problem allow for cognitive response bias. This thesis continues that trend by applying the synchrony comparison judgment method to the problem of audiovisual prior entry. Experiment 1 put this method into context with two other common psychophysical methods – the temporal order judgment and the synchrony judgment – that have been applied to the prior entry problem. The results of this experiment indicated that the temporal order judgment method was out of step with the other two methods in terms of the parameter estimates typically used to evaluate prior entry. Experiment 2 evaluated and confirmed that a specific response bias helps explain the difference in parameter estimates between the temporal order judgment method and the other two. Experiment 3 evaluated the precision of the synchrony comparison judgment method. The results indicated that the method was precise enough to detect potentially small prior entry effect sizes, and that it afforded the ability to detect those participants with points of subjective synchrony that deviate substantially from zero. Finally, Experiment 4 applied the synchrony comparison judgment method to a prior entry scenario. A prior entry effect was not realized. Overall, this thesis highlights the drawbacks of all previous methods used to evaluate audiovisual perception, including prior entry, and validates the use of the synchrony comparison judgment. Further, due to the resistance of this method to response bias, this result now stands as the most convincing evidence yet against the prior entry phenomenon.

Prior entry refers to the notion that attended stimuli are perceived sooner than unattended stimuli due to a speed up in sensory processing. The century long debate regarding the prior entry phenomenon’s existence has always been grounded in the degree to which the methods applied to the problem allow for cognitive response bias. This thesis continues that trend by applying the synchrony comparison judgment method to the problem of audiovisual prior entry. Experiment 1 put this method into context with two other common psychophysical methods – the temporal order judgment and the synchrony judgment – that have been applied to the prior entry problem. The results of this experiment indicated that the temporal order judgment method was out of step with the other two methods in terms of the parameter estimates typically used to evaluate prior entry. Experiment 2 evaluated and confirmed that a specific response bias helps explain the difference in parameter estimates between the temporal order judgment method and the other two. Experiment 3 evaluated the precision of the synchrony comparison judgment method. The results indicated that the method was precise enough to detect potentially small prior entry effect sizes, and that it afforded the ability to detect those participants with points of subjective synchrony that deviate substantially from zero. Finally, Experiment 4 applied the synchrony comparison judgment method to a prior entry scenario. A prior entry effect was not realized. Overall, this thesis highlights the drawbacks of all previous methods used to evaluate audiovisual perception, including prior entry, and validates the use of the synchrony comparison judgment. Further, due to the resistance of this method to response bias, this result now stands as the most convincing evidence yet against the prior entry phenomenon.

Prior entry refers to the notion that attended stimuli are perceived sooner than unattended stimuli due to a speed up in sensory processing. The century long debate regarding the prior entry phenomenon’s existence has always been grounded in the degree to which the methods applied to the problem allow for cognitive response bias. This thesis continues that trend by applying the synchrony comparison judgment method to the problem of audiovisual prior entry. Experiment 1 put this method into context with two other common psychophysical methods – the temporal order judgment and the synchrony judgment – that have been applied to the prior entry problem. The results of this experiment indicated that the temporal order judgment method was out of step with the other two methods in terms of the parameter estimates typically used to evaluate prior entry. Experiment 2 evaluated and confirmed that a specific response bias helps explain the difference in parameter estimates between the temporal order judgment method and the other two. Experiment 3 evaluated the precision of the synchrony comparison judgment method. The results indicated that the method was precise enough to detect potentially small prior entry effect sizes, and that it afforded the ability to detect those participants with points of subjective synchrony that deviate substantially from zero. Finally, Experiment 4 applied the synchrony comparison judgment method to a prior entry scenario. A prior entry effect was not realized. Overall, this thesis highlights the drawbacks of all previous methods used to evaluate audiovisual perception, including prior entry, and validates the use of the synchrony comparison judgment. Further, due to the resistance of this method to response bias, this result now stands as the most convincing evidence yet against the prior entry phenomenon.