Effects of caffeine on persuasion and attitude change:the role of secondary tasks in manipulating systematic message processing

Two experiments are reported that examine the effects of caffeine consumption on attitude change by using different secondary tasks to manipulate message processing. The first experiment employed an orientating task whilst the second experiment employed a distracter task. In both experiments participants consumed an orange-juice drink that either contained caffeine (3.5?mg/kg body weight) or did not contain caffeine (placebo) prior to reading a counter-attitudinal communication. The results across both experiments were similar. When message processing was reduced or under high distraction, there was no attitude change irrespective of caffeine consumption. However, when message processing was enhanced or under low distraction, there was greater attitude change in the caffeine vs. placebo conditions. Furthermore, attitudes formed after caffeine consumption resisted counter-persuasion (Experiment 1) and led to indirect attitude change (Experiment 2). The extent that participants engaged in message-congruent thinking mediated the amount of attitude change. These results provide evidence that moderate amounts of caffeine increase systematic processing of the arguments in the message resulting in greater agreement.

Intentional forgetting in depressed states

The aim of this thesis was to extend previous research on intentional forgetting in depressed states. The first experiment used the think/no-think paradigm, and found that although dysphoric individuals were significantly worse at suppressing emotional (positive and negative) words than non-dysphoric individuals, both groups were unsuccessful at direct thought suppression. However, there was no effect of rumination on dysphoric individuals' ability to intentionally forget material. Furthermore, there was also no group differences in attentional measures of Stroop and IDEO. The second experiment involved modifying the TNT task, by including the use of substitute words in the suppression phase, in order to determine whether recalling substitute words during suppression would increase the level of forgetting. The findings from the study revealed that both dysphoric and non-dysphoric individuals were successful at intentionally forgetting neutral words using a thought substitution strategy. However, both groups were impaired at suppressing words in the direct thought substitution condition. The third experiment investigated the influence of thought substitution on intentional forgetting of emotional words in dysphoria. The study replicated experiment two, but used emotional (i.e. positive and depression-relevant) words instead of neutral words. The study found that dysphoric individuals were still impaired in their ability to suppress emotional material. Furthermore, dysphoric individuals were recalling significantly more depression­ relevant respond and previously-suppressed words. The fourth experiment examined the role of executive control in intentional forgetting. In the study, dysphoric and non­ dysphoric participants were categorised as having good or poor executive control based on their scores on the operation span with words task (OSPAN). The study found that non-dysphoric individuals with good control demonstrated successful suppression. However, dysphoric individuals with good control were unsuccessful at suppression. The fifth experiment investigated whether experimentally induced changes in mood state would alter an individual's ability to intentionally forget emotional material. Non-dysphoric healthy participants were given a positive or negative autobiographical memory and music mood induction. They completed two modified think/no-think tasks, one prior to the mood induction and one after the mood induction. The study found that transient negative mood state impaired intentional forgetting of depression-relevant material. Summary: Taken together, the findings suggest that individuals in a depressed mood are impaired in their ability to intentionally forget emotional material, even with the use of a thought substitution strategy. Furthermore, the findings implicate poor executive control and negative mood state in impaired intentional forgetting. An important theme emerging from the findings was the role of an inhibitory mechanism in intentional forgetting. The findings reported in this thesis suggest that thought substitution involves engaging an inhibitory control mechanism that contributes to successful intentional forgetting. The findings have clear implications on depressed individuals everyday functioning, and suggest that even with the presence of effective distraction, dysphoric indivduals are imapired in their ability to suppress emotional material. Furthermore, it is suggested that impaired intentional forgetting of emotional material may contribute to the maintenance of depressed mood, and could potentially worsen ongoing depression.

A comparison between static and kinetic visual attention as a means of detecting age-related deterioration of the visual system and driving performance

A critical review of previous research revealed that visual attention tests, such as the Useful Field of View (UFOV) test, provided the best means of detecting age-related changes to the visual system that could potentially increase crash risk. However, the question was raised as to whether the UFOV, which was regarded as a static visual attention test, could be improved by inclusion of kinetic targets that more closely represent the driving task. A computer program was written to provide more information about the derivation of UFOV test scores. Although this investigation succeeded in providing new information, some of the commercially protected UFOV test procedures still remain unknown. Two kinetic visual attention tests (DRTS1 and 2), developed at Aston University to investigate inclusion of kinetic targets in visual attention tests, were introduced. The UFOV was found to be more repeatable than either of the kinetic visual attention tests and learning effects or age did not influence these findings. Determinants of static and kinetic visual attention were explored. Increasing target eccentricity led to reduced performance on the UFOV and DRTS1 tests. The DRTS2 was not affected by eccentricity but this may have been due to the style of presentation of its targets. This might also have explained why only the DRTS2 showed laterality effects (i.e. better performance to targets presented on the left hand side of the road). Radial location, explored using the UFOV test, showed that subjects responded best to targets positioned to the horizontal meridian. Distraction had opposite effects on static and kinetic visual attention. While UFOV test performance declined with distraction, DRTS1 performance increased. Previous research had shown that this striking difference was to be expected. Whereas the detection of static targets is attenuated in the presence of distracting stimuli, distracting stimuli that move in a structured flow field enhances the detection of moving targets. Subjects reacted more slowly to kinetic compared to static targets, longitudinal motion compared to angular motion and to increased self-motion. However, the effects of longitudinal motion, angular motion, self-motion and even target eccentricity were caused by target edge speed variations arising because of optic flow field effects. The UFOV test was more able to detect age-related changes to the visual system than were either of the kinetic visual attention tests. The driving samples investigated were too limited to draw firm conclusions. Nevertheless, the results presented showed that neither the DRTS2 nor the UFOV tests were powerful tools for the identification of drivers prone to crashes or poor driving performance.

Influence of personal mobile phone ringing and usual intention to answer on driver error

Given evidence of effects of mobile phone use on driving, and also legislation, many careful drivers refrain from answering their phones when driving. However, the distracting influence of a call on driving, even in the context of not answering, has not been examined. Furthermore, given that not answering may be contrary to an individual’s normal habits, this study examined whether distraction caused by the ignored call varies according to normal intention to answer whilst driving. That is, determining whether the effect is more than a simple matter of noise distraction. Participants were 27 young drivers (18-29 years), all regular mobile users. A Theory of Planned Behaviour questionnaire examined predictors of intention to refrain from answering calls whilst driving. Participants provided their mobile phone number and were instructed not to answer their phone if it were to ring during a driving simulation. The simulation scenario had seven hazards (e.g. car pulling out, pedestrian crossing) with three being immediately preceded by a call. Infractions (e.g. pedestrian collisions, vehicle collisions, speed exceedances) were significantly greater when distracted by call tones than with no distraction. Lower intention to ignore calls whilst driving correlated with a larger effect of distraction, as was feeling unable to control whether one answered whilst driving (Perceived Behavioural Control). The study suggests that even an ignored call can cause significantly increased infractions in simulator driving, with pedestrian collisions and speed exceedances being striking examples. Results are discussed in relation to cognitive demands of inhibiting normal behaviour and to drivers being advised to switch phones off whilst driving.

Guidelines for audio-enhancement of graphical user Interface widgets

Audio feedback remains little used in most graphical user interfaces despite its potential to greatly enhance interaction. Not only does sonic enhancement of interfaces permit more natural human-computer communication but it also allows users to employ an appropriate sense to solve a problem rather than having to rely solely on vision. Research shows that designers do not typically know how to use sound effectively; subsequently, their ad hoc use of sound often leads to audio feedback being considered an annoying distraction. Unlike the design of purely graphical user interfaces for which guidelines are common, the audio-enhancement of graphical user interfaces has (until now) been plagued by a lack of suitable guidance. This paper presents a series of empirically substantiated guidelines for the design and use of audio-enhanced graphical user interface widgets.