Force- and Space-Related Associations in Number Processing
Mon-B21-Talk III-02
Presented by: Alex Miklashevsky
BACKGROUND
Many studies demonstrated associations between smaller numbers and left space as well as larger numbers and right space. Almost all previous studies used lateralized motor (i.e., left or right) responses, and there is little evidence that these associations appear when no lateralized motor response is required. It raises the question of whether such associations are an intrinsic part of number semantics or emerge at the response stage.
METHOD
We recorded passive holding grip forces during processing of small numbers (from 1 to 4) and large numbers (from 6 to 9) in two experiments. In Experiment 1, participants performed a shallow task (“Is it a number or a letter?”); in Experiment 2, a semantically deeper magnitude judgment task (“Is this number larger or smaller than five?”) was performed.
RESULTS
Although we instructed participants to keep their grip force constant, it spontaneously changed in both experiments: In the numerical decision task, smaller numbers led to a greater force increase in the left than in the right hand. In the magnitude judgment task, smaller numbers increased the left-hand holding force, and larger numbers increased the right-hand holding force. This effect emerged earlier and lasted longer than in the shallow task.
DISCUSSION
For the first time, we demonstrated spatial associations of numbers in passive holding force. Our results suggest that (1) spatial-numerical associations can emerge without an instructed motor response and (2) the timing and strength of such associations depend on the cognitive task.
Many studies demonstrated associations between smaller numbers and left space as well as larger numbers and right space. Almost all previous studies used lateralized motor (i.e., left or right) responses, and there is little evidence that these associations appear when no lateralized motor response is required. It raises the question of whether such associations are an intrinsic part of number semantics or emerge at the response stage.
METHOD
We recorded passive holding grip forces during processing of small numbers (from 1 to 4) and large numbers (from 6 to 9) in two experiments. In Experiment 1, participants performed a shallow task (“Is it a number or a letter?”); in Experiment 2, a semantically deeper magnitude judgment task (“Is this number larger or smaller than five?”) was performed.
RESULTS
Although we instructed participants to keep their grip force constant, it spontaneously changed in both experiments: In the numerical decision task, smaller numbers led to a greater force increase in the left than in the right hand. In the magnitude judgment task, smaller numbers increased the left-hand holding force, and larger numbers increased the right-hand holding force. This effect emerged earlier and lasted longer than in the shallow task.
DISCUSSION
For the first time, we demonstrated spatial associations of numbers in passive holding force. Our results suggest that (1) spatial-numerical associations can emerge without an instructed motor response and (2) the timing and strength of such associations depend on the cognitive task.
Keywords: SNARC, Mental number line, Number processing, Embodied cognition, Grip force, Motor system