Category Archives: Sem categoria

Efficiency x Thoroughness: What people know about the cost of multitasking

Researchers emphasize there are very few circumstances in which you can do two things at once without cost (relative to doing each on its own). Yet some drivers sneak a look at their phone while on the road, and some students have the television playing while they complete an assignment.

Why? One possibility is that they don’t understand the cost of multi-tasking very well. A new study (Finley, Benjamin, and McCarley, 2014) investigated that possibility.

Subjects initially practiced a tracking task: a small target moved erratically on a computer screen and the subject was to try to keep a mouse cursor atop it. 

Interleaved with practice on the tracking task, subjects practiced a standard auditory N-back task: they heard a series of digits (one every 2.4 seconds) and were asked to say whether the digits matched the one spoken 2 digits earlier (or in other versions of the task, 1 digit or 3 digits earlier). 

After a total of 3 phases of practice for each task, subjects were told that they would try to do both tasks at the same time. They were told to prioritize the tracking task; just as a driver must keep the car in the lane, they should do their best to keep the cursor near the target, but they should do their best on the N-back task. 

Then subjects got feedback on their performance on the three phases of tracking task (expressed as percent time they had the cursor on the target) and they were asked to predict their performance on the tracking task when simultaneously doing the N-back task. 

The results showed a significant drop in tracking performance when subjects had to do the N-back task at the same time. What did subjects predict?

Subjects did predict a decrement. What they could not do was predict the size. 


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Safety Differently | The cost of behavioural transactions

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Containerbrücke in Bremerhaven drohte nach Kollision einzustürzen

Am 15.2. um 9.30 Uhr geriet bei stürmischem Wind der unter Honkong-Flagge laufende Containerfrachter “Maersk Laberinto”, 89505 BRZ (IMO-Nr.: 9526978), beim Einlaufen nach Bremerhaven außer Kontrolle. Beim Drehmanöver kollidierte er trotz Schlepperassistenz mit dem bereits an der Stromkaje festgemachten, liberianischen Containerfrachter “Maersk Missouri”, 50698 BRZ (IMO-Nr.: 9155121), als ihn starke Windböen erfassten.

Außerdem wurden drei Containerbrücken des North Sea Terminal Bremerhaven (NTB) so stark beschädigt, dass für eine von ihnen stundenlang Einsturzgefahr bestand. Die 1800 Tonnen schwere Brücke war beim Aufprall aus den Führungsschienen gedrückt worden. Die anderen beiden Entladebrücken wurden zwar weniger stark in Mitleidenschaft gezogen, waren aber ebenfalls nicht mehr einsatzfähig. Der Gefahrenbereich wurde sofort weiträumig abgesperrt und gesichert, der Löschbetrieb dort gestoppt. Ein Auslaufverbot wurde für beide Schiffe ausgesprochen.

Statiker versuchten derweil, die einsturzgefährdete Containerbrücke abzustützen und zu sichern. Mit Stützpfeilern wurde die stabilisiert. Es wurde vermutet, dass sie ein Totalschaden ist und zurückgebaut werden muss. Die “Maersk Laberinto” wurde von den Schleppern “Hunte” und “Svitzer Mallaig” nach der Havarie aus dem Gefahrenbereich verholt und an einen anderen Liegeplatz an der Stromkaje gelegt.

Der Kapitän musste eine Sicherheitsleistung von 10 000 Euro zahlen. Gegen ihn wurden Ermittlungen wegen Gefährdung des Schiffsverkehrs eingeleitet. Der Schaden wurde auf mehrere Millionen Euro geschätzt. Die beiden Frachter waren hingegen nur geringfügig an der Außenhaut beschädigt. Der Betrieb am übrigen Terminal, der insgesamt über 18 Containerbrücken verfügt, war nicht gefährdet.

Quelle: Tim Schwabedissen  (

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The HAL 9000 explanation: “It can only be attributable to human error”

Originally posted on Humanistic Systems:

In 2001: A Spade Odyssey, there is a problem aboard Discovery One. The HAL 9000 computer, artificial intelligence which can talk and mimic the human brain, announces a problem.

HAL: “I’ve just picked up a fault in the AE35 unit. It’s going to go 100% failure in 72 hours.”

The AE-35 unit is a gyroscopic device used to maintain the communications link between with mission control by keeping the satellite dish antenna aligned with Earth.

Dr David Bowman goes outside the ship in a spherical Extravehicular Activity (EVA) pod to retrieve and replace the malfunctioning unit, and returned to the pod bay, where he and Dr Frank Poole carry out extensive diagnostics. They can’t find any defects. The pair radio Mission Control in Houston. Mission Control says that HAL, the supposedly “foolproof and incapable of error” 9000 computer may have made an error. Their SAL 9000 unit, the twin…

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‘Human error’: The handicap of human factors, safety and justice | Humanistic Systems

As someone who think that the maritime industry still is an error-inducing, blame-attributing system, I recommend this link:

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Passage Planning: an image


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2014/01/07 · 13:30

SHORTIES: Safety first — for whom?

In 1994, the American scholar Charles Perrow wrote an article named “Accidents in High-Risk Systems”, in which he reviews his theory of “normal accidents”.

On pages 14 and 15, he writes:

“Another interesting systemic factor that influences the number of accidents and their prevention is the matter of close proximity of elites to operating systems. (…) Thus, the nature of the victims im contact with the system should have some effect upon the safety of that system.”

This can be useful to understand why airplane hijackings are usually treated so differently from ship hijackings and why the aerospace industry is error-avoiding, while the maritime industry is error-prone, for example. The elite may be involved with shipping, but is committed to flying.

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