Sometimes I get distracted.. #procrastination #vection #husky #haircut #instagood #contemporaryart #memes

       Source: Webster’s Unabridged New Twentieth Century Dictionary, 1956

see the tracks coming toward you? that's optic flow! When riding the roller coaster, aside from the inertia and the feeling of the air against your face, you know that you are moving because of the movement of the things you see in your environment. That movement, which is relative to the one riding the roller coaster, is called optic flow. According to Redlick, Jenkin & Harris in 2001, distance travelled can be measured using optic flow cues alone. Honeybees use this technique to judge flown distances and apparently, humans can do it too! This is possible because of vection, the illusory perception of actual self-motion when in fact, only a moving world is viewed. Optic flow and the perception of distance travelled was explored in an experiment by Redlick, Jenkin and Harris. The participants experienced a virtual corridor by watching the optic flow of a person when moving through the corridor. Before the movement, a green line was presented and the participants judged the distance toward the green line. Then, the walls of the corridor started moving at different velocities and acceleration. The green line disappeared and the participants pressed the button if they think that they had reached the green line. The results showed that the participants could estimate the distance with only optic flow cues. However, the condition with low acceleration and constant velocity resulted to the overestimation of self-motion. This means that the participants think that they have travelled farther and think that they have reached the green line even if they haven’t. This result can be applied in travelling along a narrow tunnel. The virtual corridor is like a narrow tunnel with only 2 meters wide, and with no texture at the floor and ceiling to eliminate other cues aside from the optic flow therefore, in narrow tunnels, there is an enhanced sensation of speed of motion. Amazing! So perhaps roller coasters can have tunnels to make them more exciting right? Reference: Redlick, F.P, Jenkin, M. & Harris, L.R. (2001). Humans can use optic flow to estimate distance of travel. Vision Research, 41, 213 - 219. By: Dana Esperanza S. Pancho

Vection is the sensation of movement of the body in space produced purely by visual stimulation. Everyone is familiar with the impression of self-motion experienced when watching a moving train through the windows of a stationary train. Powerful experiences of this kind occur when viewing surround cinema (IMAX) and virtual reality displays, which fill much of the visual field. Vection can be linear (apparent forward or backward motion) or angular (corresponding to angular body motion). The basis of vection lies in the close association between the processing of visual and vestibular motion in the brain. In part, this perceptual response to sustained visual motion has probably evolved as an adaptation to the fact that signals from the vestibular apparatus in the inner ear decay quite quickly during constant rotation or linear movement of the head. The sensation of vection produced purely by visual stimulation tends to build up fairly slowly, in a way that complements the decay of the vestibular sensation of movement. So, when we rotate with respect to a stationary visual world, the vection reinforces the sense that it is we who are moving, not the visual world itself, which we expect to be stable.