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[1] [2] [3] The Doppler effect is named after the physicist Christian Doppler, who described the phenomenon in 1842. A common example of Doppler shift is the change of pitch heard when a vehicle sounding a horn approaches and recedes from an observer. Compared to the emitted frequency, the received frequency is higher during the approach ...
Posner devised a scheme of using valid and invalid cues across trials. In valid trials, the stimulus is presented in the area as indicated by the cue. For example, if the cue was an arrow pointing to the right, the subsequent stimulus indeed did appear in the box on the right.
An alternative method that has been hypothesized is through the use of the Doppler shift. [14] A Doppler shift occurs when there is relative motion between a sound source and a perceiver and slightly shifts the perceived frequency of the sound. When a flying bird is changing direction, the amplitude of the Doppler shift between it and an ...
At radio frequencies the amount of bending cannot be measured directly; instead, the bending can be calculated using the Doppler shift of the signal given the geometry of the emitter and receiver. The amount of bending can be related to the refractive index by using an Abel transform on the formula relating bending angle to refractivity.
Task switching, or set-shifting, is an executive function that involves the ability to unconsciously shift attention between one task and another. In contrast, cognitive shifting is a very similar executive function, but it involves conscious (not unconscious) change in attention.
Cognitive shifting is the mental process of consciously redirecting one's attention from one fixation to another. In contrast, if this process happened unconsciously, then it is referred to as task switching.
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For example, a radar operator would be unlikely to miss a rare target at the end of a watch if it were a large bright flashing signal, but might miss a small dim signal. Under most conditions, vigilance decrement becomes significant within the first 15 minutes of attention, [ 5 ] but a decline in detection performance can occur more quickly if ...