MacIver suggests that because it is too expensive, metabolically speaking, for the knifefish to sense beyond a certain point, the fish needs to restrict its sensory space, unlike passive-sensing animals like humans, which dont invest energy in sensing.
Interestingly, the researchers also showed that when the knifefish is in water with increased conductivity, which decreases the fishs sensing ability, the animal modifies its behavior by swimming more slowly, decreasing the stopping motor volume and keeping it roughly equal to the sensory volume. This modification ensures the fish can continue to catch food and not swim past or collide with its prey.
Back to the deer in the headlights. According to the National Highway Traffic Safety Administration, only 20 percent of driving occurs at night yet more than half of human fatalities occur at night. MacIver thinks this reflects the huge difference in the relationship between the sensory volume (diminished by darkness) and the stopping motor volume (greatly increased by the inertia of the car) -- very unlike the situation we are used to in broad daylight.
Unlike the knifefish, humans dont seem to be very good at modifying their behavior to reflect conditions. At best, its guesswork, said MacIver. If we had a system that could, at night, put us back in the deliberative mode, by alerting us if we are in reactive or collision mode, we could do a lot of good.
Such a system might take into consideration pavement conditions, fog, snow or sleet, the drivers eyesight, which may be reduced due to age, cataracts or not wearing necessary eyewear, and whether or not the driver is using a cell phone, which reduces reaction time.
Of course, the technology isnt there yet, but MacIver and his team, with their method of quantifying and comparing sensing and movement volumes, have given researchers a good place to start.
|Contact: Megan Fellman|