Understanding the Impact of Time Pressure and Automation Support in a Visual Search Task

OBJECTIVE

To understand the impact of time pressure and automated decision support systems (DSS) in a simulated medical visual search task.

BACKGROUND

Time pressure usually impairs manual performance in visual search tasks, but DSS support might neutralize this negative effect. Moreover, understanding the impact of time pressure and DSS support seems relevant for many real-world applications of visual search.

METHOD

We used a visual search paradigm where participants had to search for target letters in a simulated medical image. Participants performed the task either manually or with support of a highly reliable DSS. Time pressure was varied within-subjects by either a trialwise time-pressure manipulation (Experiment 1) or a blockwise manipulation (Experiment 2). Performance was assessed based on signal detection measures. To further analyze visual search behavior, a mouse-over approach was used.

RESULTS

In both experiments, results showed impaired sensitivity under high compared to low time pressure in the manual condition, but no negative effect of time pressure when working with a highly reliable DSS. Moreover, participants searched less under time pressure and when receiving DSS support, indicating participants followed the automation without thoroughly checking recommendations. However, the human-DSS team's sensitivity was always worse than that of the DSS alone, independent of the strength of time pressure.

CONCLUSION

Negative effects of time pressure can be ameliorated when receiving support by a DSS, but joint overall performance remains below DSS-alone performance.

APPLICATION

Highly reliable DSS seem capable of ameliorating the negative impact of time pressure in complex detection tasks.

Knowing When to Pass: The Effect of AI Reliability in Risky Decision Contexts

OBJECTIVE

This study manipulates the presence and reliability of AI recommendations for risky decisions to measure the effect on task performance, behavioral consequences of trust, and deviation from a probability matching collaborative decision-making model.

BACKGROUND

Although AI decision support improves performance, people tend to underutilize AI recommendations, particularly when outcomes are uncertain. As AI reliability increases, task performance improves, largely due to higher rates of compliance (following action recommendations) and reliance (following no-action recommendations).

METHODS

In a between-subject design, participants were assigned to a high reliability AI, low reliability AI, or a control condition. Participants decided whether to bet that their team would win in a series of basketball games tying compensation to performance. We evaluated task performance (in accuracy and signal detection terms) and the behavioral consequences of trust (via compliance and reliance).

RESULTS

AI recommendations improved task performance, had limited impact on risk-taking behavior, and were under-valued by participants. Accuracy, sensitivity (d'), and reliance increased in the high reliability AI condition, but there was no effect on response bias (c) or compliance. Participant behavior was only consistent with a probability matching model for compliance in the low reliability condition.

CONCLUSION

In a pay-off structure that incentivized risk-taking, the primary value of the AI recommendations was in determining when to perform no action (i.e., pass on bets).

APPLICATION

In risky contexts, designers need to consider whether action or no-action recommendations will be more influential to design appropriate interventions.

The (Im)perfect Automation Schema: Who Is Trusted More, Automated or Human Decision Support?

OBJECTIVE

This study's purpose was to better understand the dynamics of trust attitude and behavior in human-agent interaction.

BACKGROUND

Whereas past research provided evidence for a perfect automation schema, more recent research has provided contradictory evidence.

METHOD

To disentangle these conflicting findings, we conducted an online experiment using a simulated medical X-ray task. We manipulated the framing of support agents (i.e., artificial intelligence (AI) versus expert versus novice) between-subjects and failure experience (i.e., perfect support, imperfect support, back-to-perfect support) within subjects. Trust attitude and behavior as well as perceived reliability served as dependent variables.

RESULTS

Trust attitude and perceived reliability were higher for the human expert than for the AI than for the human novice. Moreover, the results showed the typical pattern of trust formation, dissolution, and restoration for trust attitude and behavior as well as perceived reliability. Forgiveness after failure experience did not differ between agents.

CONCLUSION

The results strongly imply the existence of an imperfect automation schema. This illustrates the need to consider agent expertise for human-agent interaction.

APPLICATION

When replacing human experts with AI as support agents, the challenge of lower trust attitude towards the novel agent might arise.

A global and local perspective of interruption frequency in a visual search task

We investigated the impact of frequency of interruptions in a simulated medical visual search task. Participants (N = 150) performed the visual search task during which they were interrupted by a number-classification task in 25, 50, or 75% of all trials, respectively, reflecting the frequency conditions (i.e., low, mid, high). Target presence (i.e., present vs. absent) and interruption (i.e., uninterrupted vs. interrupted) were varied within-subjects, and interruption frequency was varied between-subjects. Globally, on a frequency condition level, participants in the low frequency condition had longer mean response times (RT) for the primary visual search task than in the high condition, but there were no other performance differences between the three frequency conditions. Locally, on the level of specific interruption effects, accuracy decreased directly after interruptions for target present but not for target absent trials. Furthermore, interruptions caused significant interruption costs, reflected in slower overall RTs in interrupted than in uninterrupted trials. The combined findings show that especially for critical visual search tasks as in the medical field, interruptions—regardless of frequency—should be avoided.

Human Performance Consequences of Automated Decision Aids: The Impact of Time Pressure

OBJECTIVE

The study addresses the impact of time pressure on human interactions with automated decision support systems (DSSs) and related performance consequences.

BACKGROUND

When humans interact with DSSs, this often results in worse performance than could be expected from the automation alone. Previous research has suggested that time pressure might make a difference by leading humans to rely more on a DSS.

METHOD

In two laboratory experiments, participants performed a luggage screening task either manually, supported by a highly reliable DSS, or by a low reliable DSS. Time provided for inspecting the X-rays was 4.5 s versus 9 s varied within-subjects as the time pressure manipulation. Participants in the automation conditions were either shown the automation's advice prior (Experiment 1) or following (Experiment 2) their own inspection, before they made their final decision.

RESULTS

In Experiment 1, time pressure compromised performance independent of whether the task was performed manually or with automation support. In Experiment 2, the negative impact of time pressure was only found in the manual but not in the two automation conditions. However, neither experiment revealed any positive impact of time pressure on overall performance, and the joint performance of human and automation was mostly worse than the performance of the automation alone.

CONCLUSION

Time pressure compromises the quality of decision-making. Providing a DSS can reduce this effect, but only if the automation's advice follows the assessment of the human.

APPLICATION

The study provides suggestions for the effective implementation of DSSs in addition to supporting concerns that highly reliable DSSs are not used optimally by human operators.

Challenging presumed technological superiority when working with (artificial) colleagues

Technological advancements are ubiquitously supporting or even replacing humans in all areas of life, bringing the potential for human-technology symbiosis but also novel challenges. To address these challenges, we conducted three experiments in different task contexts ranging from loan assignment over X-Ray evaluation to process industry. Specifically, we investigated the impact of support agent (artificial intelligence, decision support system, or human) and failure experience (one vs. none) on trust-related aspects of human-agent interaction. This included not only the subjective evaluation of the respective agent in terms of trust, reliability, and responsibility, when working together, but also a change in perspective to the willingness to be assessed oneself by the agent. In contrast to a presumed technological superiority, we show a general advantage with regard to trust and responsibility of human support over both technical support systems (i.e., artificial intelligence and decision support system), regardless of task context from the collaborative perspective. This effect reversed to a preference for technical systems when switching the perspective to being assessed. These findings illustrate an imperfect automation schema from the perspective of the advice-taker and demonstrate the importance of perspective when working with or being assessed by machine intelligence.

Trust Me, I’m Not a Doctor! Determinants of Laypersons’ Trust in Medical Decision Aids: Experimental Study (Preprint)

Background

Objective

Methods

Results

Conclusions

Trial Registration

Visual search behavior and performance in luggage screening: effects of time pressure, automation aid, and target expectancy

Visual inspection of luggage using X-ray technology at airports is a time-sensitive task that is often supported by automated systems to increase performance and reduce workload. The present study evaluated how time pressure and automation support influence visual search behavior and performance in a simulated luggage screening task. Moreover, we also investigated how target expectancy (i.e., targets appearing in a target-often location or not) influenced performance and visual search behavior. We used a paradigm where participants used the mouse to uncover a portion of the screen which allowed us to track how much of the stimulus participants uncovered prior to their decision. Participants were randomly assigned to either a high (5-s time per trial) or a low (10-s time per trial) time-pressure condition. In half of the trials, participants were supported by an automated diagnostic aid (85% reliability) in deciding whether a threat item was present. Moreover, within each half, in target-present trials, targets appeared in a predictable location (i.e., 70% of targets appeared in the same quadrant of the image) to investigate effects of target expectancy. The results revealed better detection performance with low time pressure and faster response times with high time pressure. There was an overall negative effect of automation support because the automation was only moderately reliable. Participants also uncovered a smaller amount of the stimulus under high time pressure in target-absent trials. Target expectancy of target location improved accuracy, speed, and the amount of uncovered space needed for the search.Significance Statement Luggage screening is a safety-critical real-world visual search task which often has to be done under time pressure. The present research found that time pressure compromises performance and increases the risk to miss critical items even with automation support. Moreover, even highly reliable automated support may not improve performance if it does not exceed the manual capabilities of the human screener. Lastly, the present research also showed that heuristic search strategies (e.g., areas where targets appear more often) seem to guide attention also in luggage screening.

Investigating limits of task prioritization in dual-tasking: evidence from the prioritized processing and the psychological refractory period paradigms

Dual-tasking often requires prioritizing one task over the other. For example, in the psychological refractory period (PRP) paradigm, participants are instructed to initially respond to Task 1 (T1) and only then to Task 2 (T2). Furthermore, in the prioritized processing paradigm (PP), participants are instructed to perform T2 only if T1 was a no-go trial-requiring even more prioritization. The present study investigated the limits of task prioritization. Two experiments compared performance in the PRP paradigm and the PP paradigm. To manipulate task prioritization, tasks were rewarded differently (e.g., high reward for T1, low reward for T2, and vice versa). We hypothesized (a) that performance will improve for the highly rewarded task (Experiments 1 and 2) and (b) that there are stronger reward effects for T1 in the PRP than in the PP paradigm (Experiment 2). Results showed an influence of reward on task prioritization: For T1, high reward (compared to low reward) caused a speed-up of responses that did not differ between the two paradigms. However, for T2, reward influenced response speed selectively in the PP paradigm, but not in the PRP paradigm. Based on paradigm-specific response demands, we propose that the coordination of two motor responses plays a crucial role in prioritizing tasks and might limit the flexibility of the allocation of preparatory capacity.

Are model parameters linked to processing stages? An empirical investigation for the ex-Gaussian, ex-Wald, and EZ diffusion models

In previous research, the parameters of the ex-Gaussian distribution have been subject to a wide variety of interpretations. The present study investigated whether the ex-Gaussian model is capable of distinguishing effects on separate processing stages (i.e., pre-motor vs. motor). In order to do so, we used datasets where the locus of effect was quite clear. Specifically, we analyzed data from experiments comparing hand vs. foot responses-presumably differing in the motor stage-and from experiments in which the lateralized readiness potential was used to localize experimental effects into premotor vs. motor processes. Moreover, we broadened the scope to two other descriptive RT models: the ex-Wald and EZ diffusion models. To the extent possible with each of these models, we reanalyzed the RT data of 19 clearly localized experimental effects from 12 separate experiments reported in seven previously published articles. Unfortunately, we did not find a clear pattern of results for any of the models, with no clear link between effects on one of the model's parameters and effects on different processing stages. The present results suggest that one should resist the temptation to associate specific processing stages with individual parameters of the ex-Gaussian, ex-Wald, and EZ diffusion models.

Misfit dislocation free InAs/GaSb core-shell nanowires grown by molecular beam epitaxy

In this report, we present the growth and structural analyses of broken gap InAs/GaSb core-shell nanowires by molecular beam epitaxy using an Au-free approach. Depending on the shell growth temperature, two distinct growth regimes for the GaSb shells are identified resulting in conformal or tapered shells. Morphological analyses reveal a dodecagonal nanowire cross-section after GaSb shell growth. Detailed transmission electron microscope investigations from different zone axes confirm that the small lattice mismatch of 0.6% allows the deposition of 40 nm thick GaSb shells free of misfit dislocations. Additionally, an abrupt interface from InAs to GaSb is found. These nanowires are suitable for future devices such as TFETs.

Giant magnetoconductance oscillations in hybrid superconductor-semiconductor core/shell nanowire devices

The magnetotransport of GaAs/InAs core/shell nanowires contacted by two superconducting Nb electrodes is investigated, where the InAs shell forms a tube-like conductive channel around the highly resistive GaAs core. By applying a magnetic field along the nanowire axis, regular magnetoconductance oscillations with an amplitude in the order of e(2)/h are observed. The oscillation amplitude is found to be larger by 2 orders of magnitude compared to the measurements of a reference sample with normal metal contacts. For the Nb-contacted core/shell nanowire the oscillation period corresponds to half a flux quantum Φ0/2 = h/2e in contrast to the period of Φ0 of the reference sample. The strongly enhanced magnetoconductance oscillations are explained by phase-coherent resonant Andreev reflections at the Nb-core/shell nanowire interface.

Crystallization of HfO2 in InAs/HfO2 core-shell nanowires

We report the impact of deposition parameters on the structure of HfO(2) covering InAs nanowires (NWs) being potential candidates for future field-effect transistors (FETs). Molecular beam epitaxial-grown Au-free InAs NWs were covered with HfO(2) deposited by atomic-layer deposition. The impact of the film thickness as well as the deposition temperature on the occurrence and amount of crystalline HfO(2) regions was investigated by high-resolution transmission electron microscopy (TEM) and x-ray diffraction. Compared to the deposition on planar Si substrates, the formation probability of crystalline HfO(2) on InAs NWs is significantly enhanced. Here, even 3 nm thick films deposited at 250 °C are partly crystalline. Similarly, a low deposition temperature of 125 °C does not result in completely amorphous 10 nm thick HfO(2) films, they contain monoclinic as well as orthorhombic HfO(2) nanocrystals. Combining HfO(2) and Al(2)O(3) into a laminate structure is capable of suppressing the formation of crystalline HfO2 grains.

Self-catalyzed VLS grown InAs nanowires with twinning superlattices

We report on the self-catalyzed growth of InAs nanowires by molecular beam epitaxy on GaAs substrates covered by a thin silicon oxide layer. Clear evidence is presented to demonstrate that, under our experimental conditions, the growth takes place by the vapor-liquid-solid (VLS) mechanism via an In droplet. The nanowire growth rate is controlled by the arsenic pressure while the diameter depends mainly on the In rate. The contact angle of the In droplet is smaller than that of the Ga droplet involved in the growth of GaAs nanowires, resulting in much lower growth rates. The crystal structure of the VLS grown InAs nanowires is zinc blende with regularly spaced rotational twins forming a twinning superlattice.

Gate-induced transition between metal-type and thermally activated transport in self-catalyzed MBE-grown InAs nanowires

Electronic transport properties of InAs nanowires are studied systematically. The nanowires are grown by molecular beam epitaxy on a SiOx-covered GaAs wafer, without using foreign catalyst particles. Room-temperature measurements revealed relatively high resistivity and low carrier concentration values, which correlate with the low background doping obtained by our growth method. Transport parameters, such as resistivity, mobility, and carrier concentration, show a relatively large spread that is attributed to variations in surface conditions. For some nanowires the conductivity has a metal-type dependence on temperature, i.e. decreasing with decreasing temperature, while other nanowires show the opposite temperature behavior, i.e. temperature-activated characteristics. An applied gate voltage in a field-effect transistor configuration can switch between the two types of behavior. The effect is explained by the presence of barriers formed by potential fluctuations.

Nanoimprint and selective-area MOVPE for growth of GaAs/InAs core/shell nanowires

We report on the technology and growth optimization of GaAs/InAs core/shell nanowires. The GaAs nanowire cores were grown selectively by metal organic vapor phase epitaxy (SA-MOVPE) on SiO(2) masked GaAs (111)B templates. These were structured by a complete thermal nanoimprint lithography process, which is presented in detail. The influence of the subsequent InAs shell growth temperature on the shell morphology and crystal structure was investigated by scanning and transmission electron microscopy in order to obtain the desired homogeneous and uniform InAs overgrowth. At the optimal growth temperature, the InAs shell adopted the morphology and crystal structure of the underlying GaAs core and was perfectly uniform.

Realization of nanoscaled tubular conductors by means of GaAs/InAs core/shell nanowires

We investigated the transport properties of GaAs/InAs core/shell nanowires grown by molecular beam epitaxy. Owing to the band alignment between GaAs and InAs, electrons are accumulated in the InAs shell as long as the shell thickness exceeds 12 nm. By performing simulations using a Schrödinger-Poisson solver, it is confirmed that confined states are present in the InAs shell, which are depleted if the shell thickness is below a threshold value. The existence of a tubular-shaped conductor is proved by performing magnetoconductance measurements at low temperatures. Here, flux periodic conductance oscillations are observed which can be attributed to transport in one-dimensional channels based on angular momentum states.

Trapping of neutral rubidium with a macroscopic three-phase electric trap

We trap neutral ground-state rubidium atoms in a macroscopic trap based on purely electric fields. For this, three electrostatic field configurations are alternated in a periodic manner. The rubidium is precooled in a magneto-optical trap, transferred into a magnetic trap, and then translated into the electric trap. The electric trap consists of six rod-shaped electrodes in cubic arrangement, giving ample optical access. Up to 10;{5} atoms have been trapped with an initial temperature of around 20 microkelvin in the three-phase electric trap. The observations are in good agreement with detailed numerical simulations.

Continuous loading of an electrostatic trap for polar molecules

A continuously operated electrostatic trap for polar molecules is demonstrated. The trap has a volume of approximately 0.6 cm3 and holds molecules with a positive Stark shift. With deuterated ammonia from a quadrupole velocity filter, a trap density of approximately 10(8) cm(-3) is achieved with an average lifetime of 130 ms and a motional temperature of approximately 300 mK. The trap offers good starting conditions for high-precision measurements, and can be used as a first stage in cooling schemes for molecules and as a "reaction vessel" in cold chemistry.

Two-dimensional trapping of dipolar molecules in time-varying electric fields

Simultaneous two-dimensional trapping of neutral dipolar molecules in low- and high-field seeking states is analyzed. A trapping potential of the order of 20 mK can be produced for molecules such as ND3 with time-dependent electric fields. The analysis is in agreement with an experiment where slow molecules with longitudinal velocities of the order of 20 m/s are guided between four 50 cm long rods driven by an alternating electric potential at a frequency of a few kHz.

Regulation of respiration and energy transduction in cytochrome c oxidase isozymes by allosteric effectors

The binding of TNP-ATP (2' or 3'-O-(2,4,6-trinitrophenyl)-ATP) to cytochrome c oxidase (COX) from bovine heart and liver and to the two-subunit COX of Paracoccus denitrificans was measured by its change of fluorescence. Three binding sites, two with high (dissociation constant Kd = 0.2 microM) and one with lower affinity (Kd = 0.9 microM), were found at COX from bovine heart and liver, while the Paracoccus enzyme showed only one binding site (Kd = 3.6 microM). The binding of [35S]ATP alpha S was measured by equilibrium dialysis and revealed seven binding sites at the heart enzyme (Kd = 7.5 microM) and six at the liver enzyme (Kd = 12 microM). The Paracoccus enzyme had only one binding site (Kd = 16 microM). The effect of variable intraliposomal ATP/ADP ratios, but at constant total concentration of [ATP + ADP] = 5 mM, on the H+/e- stoichiometry of reconstituted COX from bovine heart and liver were studied. Above 98% ATP the H+/e- stoichiometry of the heart enzyme decreased to about half of the value measured at 100% ATP. In contrast, the H+/e-stoichiometry of the liver enzyme was not influenced by the ATP/ADP ratio. It is suggested that high intramitochondrial ATP/ADP ratios, corresponding to low cellular work load, will decrease the efficiency of energy transduction and result in elevated thermogenesis for the maintenance of body temperature.

The number of nucleotide binding sites in cytochrome C oxidase

The binding of 2'(3')-O-(2,4,6-trinitrophenyl)-adenosine-5'-triphosphate (TNP-ATP), [35S]ATP alpha S and 8-azido-[gamma-32P]ATP to isolated cytochrome c oxidase of bovine heart and liver and to the two-subunit enzyme of Paracoccus dentrificans was studied by measuring the fluorescence change or bound radioactivity, respectively. With TNP-ATP three binding sites were determined at cytochrome c oxidase from bovine heart and liver, both with two dissociation constants Kd of about 0.2 and 0.9 microM. Trypsin treatment of the enzyme from bovine heart, resulted in one binding site with a Kd of 0.3 microM. The two-subunit enzyme of Paracoccus dentrificans had only one binding site with a Kd of 3.6 microM. The binding of [35S]ATP alpha S to cytochrome c oxidase was studied by equilibrium dialysis. With the enzyme of bovine heart seven and the enzyme of liver six high-affinity binding sites with apparent Kd's of 7.5 and 12 microM, respectively, were obtained. The two-subunit enzyme of Paracoccus denitrificans had one binding site with a Kd of 20 microM. The large number of binding sites at cytochrome c oxidase from bovine heart, mainly at nuclear coded subunits, was verified by photoaffinity labelling with 8-azido-[gamma-32P]ATP.

The point mutation of mitochondrial DNA characteristic for MERRF disease is found also in healthy people of different ages

The A-to-G transition mutation in the tRNA(Lys) gene of mitochondrial DNA (mtDNA), characteristic for the maternally inherited MERRF syndrome (myoclonic epilepsy with ragged red fibers), has been identified by point mutation-specific polymerase chain reaction in extraocular muscle from 11 of 16 healthy people of different ages. No mutation was found in navel-string samples from 5 newborns, in HeLa cells, and in 2 individuals younger than 20 years. On the other hand, the mutation is present in all 5 tested 74-89-year-old individuals and in 6 of 9 20-70-year-old individuals. The amount of mutated from total mtDNA was estimated by 'mispairing PCR' in extraocular muscle of 2 individuals of 74 and 89 years to 2.0 and 2.4%, respectively. In most tissue samples the MERRF mutation occurs together with the 'common deletion' of mtDNA, which was previously shown to accumulate in healthy individuals with increasing age. It is proposed that during aging, deletions and point mutations of mtDNA accumulate, which could impair mitochondrial energetics.