Stephen H. Fairclough

A metabolic measure of mental effort

Previous studies have operationalised mental effort via various indices of psychophysiology, particularly cardiovascular measures. Metabolic measures represent a complementary approach wherein mental effort investment is explicitly linked to the process of energy mobilisation. The purpose of this study was to contrast cardiovascular variables (heart rate, 0.1 Hz component of heart rate variability) with a metabolic measure (blood glucose) of mental effort. Twenty-nine participants were exposed to Stroop stimuli over a 45 min period under two conditions: (a) congruent (i.e. 100% congruent Stroop stimuli); and (b) incongruent (i.e. 100% incongruent Stroop stimuli). Performance, blood glucose, cardiovascular activity and subjective mood were measured. The results indicated that blood glucose levels were sensitive to both Stroop and time-on-task variables, whilst cardiovascular measures were only sensitive to the latter. There was also evidence of an association between blood glucose levels and response accuracy. The implications of these findings for the operationalisation of mental effort are discussed.

Impairment of driving performance caused by sleep deprivation or alcohol: a comparative study.

A study was conducted to assess the relative impact of partial sleep deprivation (restriction to 4 h sleep before testing) and full sleep deprivation (no sleep on the night before testing) on 2 h of simulated driving, compared with an alcohol treatment (mean blood alcohol content = 0.07%). Data were collected from the 64 male participants on the primary driving task, psychophysiology (0.1 Hz heart rate variability), and subjective self-assessment. The results revealed that the full sleep deprivation and alcohol group exhibited a safety-critical decline in lane-keeping performance. The partial sleep deprivation group exhibited only noncritical alterations in primary task performance. Both sleep-deprived groups were characterized by subjective discomfort and an awareness of reduced performance capability. These subjective symptoms were not perceived by the alcohol group. The findings are discussed with reference to the development of systems for the online diagnosis of driver fatigue. Potential applications of this research include the formulation of performance criteria to be encompassed within a driver impairment monitoring system.

CRITERIA FOR DRIVER IMPAIRMENT

Most traffic accidents can be attributed to driver impairment, e.g. inattention, fatigue, intoxication, etc. It is now technically feasible to monitor and diagnose driver behaviour with respect to impairment with the aid of a limited number of in-vehicle sensors. However, a valid framework for the evaluation of driver impairment is still lacking. To provide an acceptable definition of driver impairment, a method to assess absolute and relative criteria was proposed to fulfil the paradoxical goal of defining impaired driving which is consistent yet adaptable to interindividual differences.

A research agenda for physiological computing

Abstract Physiological computing involves the direct interfacing of human physiology and computer technology, i.e. brain–computer interaction (BCI). The goal of physiological computing is to transform bioelectrical signals from the human nervous system into real-time computer input in order to enhance and enrich the interactive experience. Physiological computing has tremendous potential for interactive innovation but research activities are often disparate and uneven, and fail to reflect the multidisciplinary nature of the topic. This paper will provide a primer on detectable human physiology as an input source, a summary of relevant research and a research agenda to aid the future development of interactive systems that utilise physiological information.

THE EFFECT OF TIME HEADWAY FEEDBACK ON FOLLOWING BEHAVIOUR

A field study was conducted to assess the impact of continuous time headway feedback on following behaviour. An equipped vehicle was fitted with a microwave radar connected to a head-down display. The display was supplemented by an auditory tone which sounded if headway decreased below 1 second. Sixteen subjects participated in five consecutive sessions conducted on a U.K. motorway. The presence of the system and the time of the journey (i.e. rush hour vs off-peak) was manipulated across the experimental sessions. Results revealed that the presence of the system reduced the proportion of time the subjects spent at low headways (e.g. < 1 second). This effect was accentuated for: (a) subjects who habitually follow at shorter headways and (b) those scenarios characterised as following a lead vehicle at a constant velocity. The presence of the system increased time headway to a lead vehicle when an overtaking manoeuvre was initiated, but only in off-peak traffic. The system had no significant effect on speed-keeping behaviour or drivers mental workload.

Activation of the rostromedial prefrontal cortex during the experience of positive emotion in the context of esthetic experience. An fNIRS study

The contemplation of visual art requires attention to be directed to external stimulus properties and internally generated thoughts. It has been proposed that the medial rostral prefrontal cortex (rPFC; BA10) plays a role in the maintenance of attention on external stimuli whereas the lateral area of the rPFC is associated with the preservation of attention on internal cognitions. An alternative hypothesis associates activation of medial rPFC with internal cognitions related to the self during emotion regulation. The aim of the current study was to differentiate activation within rPFC using functional near infrared spectroscopy (fNIRS) during the viewing of visual art selected to induce positive and negative valence, which were viewed under two conditions: (1) emotional introspection and (2) external object identification. Thirty participants (15 female) were recruited. Sixteen pre-rated images that represented either positive or negative valence were selected from an existing database of visual art. In one condition, participants were directed to engage in emotional introspection during picture viewing. The second condition involved a spot-the-difference task where participants compared two almost identical images, a viewing strategy that directed attention to external properties of the stimuli. The analysis revealed a significant increase of oxygenated blood in the medial rPFC during viewing of positive images compared to negative images. This finding suggests that the rPFC is involved during positive evaluations of visual art that may be related to judgment of pleasantness or attraction. The fNIRS data revealed no significant main effect between the two viewing conditions, which seemed to indicate that the emotional impact of the stimuli remained unaffected by the two viewing conditions.

Construction of the biocybernetic loop: a case study

The biocybernetic loop describes the data processing protocol at the heart of all physiological computing systems. The loop also encompasses the goals of the system design with respect to the anticipated impact of the adaptation on user behaviour. There are numerous challenges facing the designer of a biocybernetic loop in terms of measurement, data processing and adaptive design. These challenges are multidisciplinary in nature spanning psychology and computer science. This paper is concerned with the design process of the biocybernetic loop. A number of criteria for an effective loop are described followed by a six-stage design cycle. The challenges faced by the designer at each stage of the design process are exemplified with reference to a case study where EEG data were used to adapt a computer game.

Measuring task engagement as an input to physiological computing

Task engagement is a psychological dimension that describes effortful commitment to task goals. This is a multidimensional concept that combines cognition, motivation and emotion. This dimension may be important for the development of physiological computing systems that use real-time psychophysiology to monitor user state, particularly those systems seeking to optimise performance (e.g. adaptive automation, games, automatic tutoring). Two laboratory-based experiments were conducted to investigate measures of task engagement, based on EEG, pupilometry and blood pressure. The first study exposed participants to increased levels of memory load whereas the second used performance feedback to either engage (success feedback) or disengage (failure feedback) participants. EEG variables, such as frontal theta and asymmetry, were sensitive to disengagement due to cognitive load (experiment 1) whilst changes in systolic blood pressure were sensitive to feedback of task success. Implications for the development of physiological computing systems are discussed.

Use of auditory event-related potentials to measure immersion during a computer game ☆

The degree of engagement in a computer game is determined by sensory immersion (i.e. effects of display technology) and challenge immersion (i.e. effects of task demand). Twenty participants played a computer game under two display conditions (a large TV vs. head-mounted display) with three levels of cognitive challenge (easy/hard/impossible). Immersion was defined as selective attention to external (non-game related) auditory stimuli and measured implicitly as event-related potentials (ERPs) to an auditory oddball task. The Immersive Experience Questionnaire (IEQ) was used to capture subjective indicators of immersion. The type of display had no significant influence on ERPs or responses to the IEQ. However, subjective immersion was significantly enhanced by the experience of hard and impossible demand. The amplitude of late component ERPs to oddball stimuli were significantly reduced when demand increased from easy to hard/impossible levels. We conclude that ERPs to irrelevant stimuli represent a valid method of operationalising immersion.

Effects of mood induction via music on cardiovascular measures of negative emotion during simulated driving.

A study was conducted to investigate the potential of mood induction via music to influence cardiovascular correlates of negative emotions experience during driving behaviour. One hundred participants were randomly assigned to one of five groups, four of whom experienced different categories of music: High activation/positive valence (HA/PV), high activation/negative valence (HA/NV), low activation/positive valence (LA/PV) and low activation/negative valence (LA/NV). Following exposure to their respective categories of music, participants were required to complete a simulated driving journey with a fixed time schedule. Negative emotion was induced via exposure to stationary traffic during the simulated route. Cardiovascular reactivity was measured via blood pressure, heart rate and cardiovascular impedance. Subjective self-assessment of anger and mood was also recorded. Results indicated that low activation music, regardless of valence, reduced systolic reactivity during the simulated journey relative to HA/NV music and the control (no music) condition. Self-reported data indicated that participants were not consciously aware of any influence of music on their subjective mood. It is concluded that cardiovascular reactivity to negative mood may be mediated by the emotional properties of music.