Bernd Lorenz

Mental performance during short-term and long-term spaceflight

During the last years several attempts have been made to describe changes in the mental efficiency of astronauts during space missions by means of performance monitoring studies. These studies are characterized by repeated multivariate assessment of different functions of the human information-processing system. In the present paper, a first review of performance monitoring studies during short-term and long-term spaceflight is given. Despite the comparatively small number of studies, a fairly consistent pattern of effects can be derived: Whereas no or only slight impairments of elementary and complex cognitive functions or spatial processing were found in space, clear disturbances could be identified in visuo-motor tracking and dual-task performance. Both of these latter effects appear to be closely related to adaptation to altered gravity conditions. General issues of this strategy of research are discussed which concern the disentanglement of microgravity-related effects and unspecific stress effects on mental performance under conditions of spaceflight. In addition, possible mechanisms which may be responsible for tracking disturbances under microgravity are discussed, and some directions for future human performance research in space are outlined.

Mental performance in extreme environments: results from a performance monitoring study during a 438-day spaceflight.

During their stay in a space habitat, astronauts are exposed to many different stressors that may entail detrimental effects on mood and performance. In order to monitor the effects of the space environment on different human information processing functions during an extraordinary long-term space mission, the cognitive. visuo-motor and time-sharing performance of one Russian cosmonaut was repeatedly assessed (29 times) during his 438-day stay in space. The performance tasks used were chosen from the AGARD-STRES battery and included grammatical reasoning, Sternberg memory-search, unstable tracking, and a dual-tasks consisting of unstable tracking with concurrent memory-search. In addition to performance assessment, several subjective ratings concerning mood and workload were collected. Comparisons of pre-flight, in-flight, post-flight and two follow-up assessments 6 months after the mission revealed, (1) no impairments of basic cognitive functions during the flight, (2) clear impairments of mood, feelings of raised workload, and disturbances of tracking performance and time-sharing during the first 3 weeks in space and the first 2 weeks after return to Earth, (3) an impressive stability of mood and performance during the second to fourteenth month in space, where mood and performance had returned to pre-flight baseline level, and (4) no long-lasting performance deficits at follow-up assessments. From these results it is concluded that the first 3 weeks of long-term spaceflights and the first 2 weeks back on Earth represent critical periods where adverse effects on attentional processes are to be expected, induced by the demands to adjust to the extreme environmental changes. The stability of mood and performance observed after successful adaptation to the space environment indicates that mental efficiency and emotional state can be maintained on a level as high as on Earth even during extraordinary long-term space missions.

Dual-Task Performance in Space: Results from a Single-Case Study during a Short-Term Space Mission

During spaceflights, astronauts are exposed to many stressors (e.g., microgravity, confinement) that may impair human information-processing capabilities. In order to analyze the possible effects of the space environment on human timesharing efficiency, a single-case experiment was conducted in which the time course of dual-task performance (unstable tracking with concurrent memory search) of one space crew member was monitored repeatedly (13 times) throughout an 8-day space mission. Tasks were taken from the Advisory Group for Aerospace Research and Development battery of Standardized Tests for Research with Environmental Stressors. Comparisons of in-flight, preflight, and postflight performance revealed no decrements in single-task memory search performance but did reveal clear impairments in single-task tracking and dual-task performance. From these results we conclude that psychomotor processes and higher attentional functions are particularly prone to disturbance effects in space.

Impairments of manual tracking performance during spaceflight : more converging evidence from a 20-day space mission

Studies of human performance during spaceflight have consistently revealed degradations of manual tracking performance in space. The present investigation analysed these performance decrements in more detail by applying frequency response analyses of tracking performance. It was hypothesized that tracking impairments result from two factors: at an early adaptation phase in space they primarily reflect effects of microgravity on human visuo-motor processes, whereas later into the mission they are also caused by impairments of attentional processes induced by cumulative workload and fatigue. In order to investigate this hypothesis, performance of one cosmonaut in a first-order unstable tracking task was repeatedly assessed before, during and after a 20-day space mission. Singlecase statistical analyses revealed the following effects: tracking performance declined at the first assessment in space and in two later inflight sessions compared to pre-flight baseline. Whereas the early tracking decrement was mainly due to an increase of the effective time-delay during tracking and accompanied by only minor changes of mood or workload, one of the later inflight impairments was due to an increase of effective time-delay, a decreased tracking gain, and an increase of tracking remnant, and both were associated with considerably higher workload ratings. This pattern of effects supports the two-factor hypothesis.

Changed visuomotor transformations during and after prolonged microgravity

Abstract A series of step-tracking experiments was conducted before, during, and after a 3-week space mission to assess the effects of prolonged microgravity on a non-postural motor-control task. In- and post-flight accuracy was affected only marginally. However, kinematic analyses revealed a considerable change in the underlying movement dynamics: too-small force and, thus, too-low velocity in the first part of the movements was mainly compensated by lengthening the deceleration phase of the primary movement, so that accuracy was regained at its end. The observed in-flight decrements in peak velocity and peak acceleration point to an underestimation of mass, in agreement with the re-interpretation hypothesis of Bock et. al. Post-flight no reversals of the in-flight changes (negative aftereffects) were found. Instead, there was a general slowing down, which could be due to post-flight physical exhaustion.

Impairments of manual tracking performance during spaceflight are associated with specific effects of microgravity on visuomotor transformations

In contrast to performance in cognitive tasks, tracking performance tends to deteriorate fairly consistently during spaceflight. We address the question whether this decrement results from specific effects of microgravity on motor control or from non-specific effects of the various other stressors present. In a case study we generalize the findings obtained with aiming movements, performed by the same cosmonaut with the same effectors as used for an unstable tracking task, to obtain hypotheses for specific changes of parameters of a simple model used to analyse tracking performance. Consistent with these hypotheses, we observed a reduction of limb stiffness in-flight, but a reduction of the tracking gain post-flight. The cross-task consistency of the observed changes does strongly suggest that the tracking impairment is at least partly caused by specific effects of microgravity on motor control, in particular by a mis-calibration of muscular forces which likely results from an underestimation of masses due to weightlessness.

Evaluation of Onboard Taxi Guidance Support on Pilot Performance in Airport Surface Navigation

Advanced Surface Movement Guidance and Control Systems (A-SMGCS) comprise a range of new technologies for both the flight deck and ground air traffic control and is supposed to enable increased safety and a more efficient throughput at presently highly congested major airports. A flight deck A-SMGCS module is the onboard guidance system TARMAC-AS. This module consists of controller pilot data link communication (CPDLC) and an electronic moving map (EMM), which also serves as a cockpit display of traffic information (CDTI). TARMAC-AS is evaluated in an investigation involving 49 commercial pilots who performed a series of approach, landing and taxiing simulation trials under varied visibility, which were completed in a fixed-base cockpit simulator. Results support the notion that an EMM + CPDLC + CDTI improve the effectiveness of taxi navigation. A potential negative impact of observed increased head-down times to the compelling TARMAC display on unexpected outside scene obstacle detection was not substantiated.

Display Integration Enhances Information Sampling and Decision Making in Automated Fault Management in a Simulated Spaceflight Micro-World

Fault management (FM) performance and information sampling behavior were examined while participants operated a complex micro-world that simulated system failures within a generic life-support system of a spacecraft. One group of participants was supported by an integrated display that facilitated fault identification while the other group had to rely on separated raw data readings. The effects of two modes of intelligent automation support were also examined. At a low level of automation (LOA), fault identification was generated along with an advisory on a sequence of recovery actions to be implemented manually at the operators discretion. The higher LOA generated fault identification but allowed the operator a veto against automatic implementation of the suggested recovery plan. Automated fault identification was unreliable 30% percent of the time; in these trials the automation missed fault identification, gave a false alarm to a nominal situation, or provided false or incomplete fault identification. Initiation of proper recovery when the automation failed was less accurate and slowest when operators were supplied with the non-integrated display, but only when they operated at the low LOA mode prior to the failure. This effect was associated with superior information sampling behavior at the higher LOA when automation was reliable. Display integration and the higher LOA thus supported more efficient sampling of fault relevant displays thereby, promoting better fault state awareness in the presence of reliable automation. This also benefited fault management when the automation failed.

Design of a pathway display for a retinal scanning HMD

During approach and landing the pilot performs a high-workload task of switching the attention between instrument in-formation and the outside scene. Superimposing both visual domains in head-up (HUD) or head-mounted displays (HMD) reduces the visual scanning load of this task. These displays are collimated at optical infinity; therefore, prevent the pilots eye from permanent accommodation between both visual domains. Besides these performance benefits, visual clutter and attention fixation, i.e. inattentiveness to outside scene events while attending on HUD symbologies, are found to be performance cost factors. Conformal symbology and flight-phase adapted de-cluttering has been found to be prom-ising approaches to overcome these problems. In pursuit of these two approaches, the current paper describes the design of a new pathway display on a monocular head-mounted retinal scanning display and its implementation in DLRs generic cockpit simulator. The pathway can be regarded as a means of linking an instrument symbology (the tunnel) with a virtual element of the outside scene (the in-tended flight path). Scene-linked symbology appear to be part of the outside world, e.g. an instrument reading like air-speed, heading, or altitude that is changing its display location conformal with the gate element of the tunnel symbology moving towards the pilot. Examples of flight phase-adaptive de-cluttering is to successively reduce or remove symbol-ogy when the conformal outside element becomes visible (e.g. the runway). In addition the display includes a conformal presentation of the terrain. A checker board pattern representing the terrain is dynamically generated from worldwide available SRTM-3 data.

Geschlechtsunterschiede bei Wahlreaktionsleistungen im eignungsdiagnostischen Kontext

Zusammenfassung: Bei 243 Bewerbern fur die Ausbildung zum Flugverkehrslotsen (166 Manner, 77 Frauen) wurden Geschlechtsunterschiede in den Leistungen bei einem 8-fach Wahlreaktionstest mit Reiz-Reaktions-Inkompatibilitat-- untersucht. Die Reaktionszeiten wurden aufgespalten in Entscheidungszeiten (= Zeitintervall zwischen Signal und Loslassen einer Ruhetaste) und Bewegungszeiten (= Zeitintervall zwischen Loslassen der Ruhetaste und Drucken der Zieltaste). Erganzend wurden Geschlechtsunterschiede in einem weiteren perzeptiv-motorischen Leistungstest (Bourdon-Buchstabendurchstreichen) untersucht. Ergebnisse: (1) Wahrend die Entscheidungszeiten sich in beiden Gruppen nicht unterschieden, zeigten Manner signifikant kurzere Bewegungszeiten als Frauen. (2) Frauen hatten signifikant haufigere Auslassungen (4.6%) als Manner (2.1%). (3) Frauen hatten signifikant schnellere Leistungen im Bourdon-Buchstabendurchstreichen. Anhand der Ergebnisse wird vermutet, das sich das in der Literatur zu Geschlechtsdifferenzen be...