amplitude
the distance between the two target centers in aiming tasks ("A" in Fitts' Law)
timing errors
-skills requiring timing accuracy follow different principles than those requiring spatial accuracy
-performers are able to produce shorter movement times more accurately than longer movement times
Movement timing
- skills with temporal goals seem to follow somewhat different principles that those having purely spatial goals
-decreasing the movement time has the effect of decreasing the timing error for skills with temporal goals making the movement more accurate in time, not less.
spatial anticipation
the anticipation of which of several possible stimuli will occur, sometimes called event anticipation
temporal anticipation
the anticipation of when a given stimulus will arrive or when a movement is to be made
Bimanual Aiming Tasks
both limbs could be assigned identical tasks with either low or high IDs, or the limbs could be assigned to different (incongruent) tasks (using two hands)
Continuous Bimanual Timing
-when controlling the continuous movement of two limbs, each with its own spatial or temporal goal (or both), because the movements are ongoing, the executive can do the following:
-use common movement command to control the movement of both limbs
-switch attention rapidly between the executions of the two tasks
anti-phase
a coordination timing pattern in which two movement components oscillate in opposition (180 degree relative phase)
effective target width
-standard deviation of the target end points
-this measure is analogous to the target size that the subject "actually used" in making the action with the required MT
Fitts' Law
-states that MT is constant whenever the ratio of the movement amplitude (A) to target width (W) remains constant
- errors increase if movement is further or faster
-MT is linearly related to the index of difficulty
index of difficulty
-define the "difficulty" of the various combinations of A and W
-MT is linearly related
in-phase
a coordination timing pattern in which two movement components oscillate in synchrony (0 degree relative phase)
self-organization
a view that describes motor control as emerging from the interaction of the components of the movement system and the environment
speed-accuracy trade-off
- the tendency for people to "give up" speed in order to trade speed of for acceptable levels of accuracy
-as speed increases accuracy decreases
-one of the most fundamental principles of movement behavior
width
the size of a target in aiming tasks ("W" in Fitts' Law)
