Motor and cognitive interference effects on unimanual tapping rates

Experiments conducted on both normal and disordered populations have led to the hypothesis that the left hemisphere's specialization for language results from its control over motor activities. This control is reflected in the lateralized disruption of manual activity during cerebral time-sharing tasks. Recent studies have challenged this hypothesis, stating that the interference effects reflect both cognitive and motor mechanisms in the left hemisphere. This experiment investigates whether the left hemisphere's control over speech involves both of these components or is purely motor. The question was examined by measuring the effect of concurrent hemispheric activity on single-finger tapping rates. Forty subjects tapped under two conditions: speaking and listening. The data show there may be both motor and cognitive mechanisms involved in left-hemisphere control.     

Self-defence and National Defence [1]

ABSTRACT The paper begins with the suggestion that the aura of respectability that surrounds the notion of self-defence may render that notion suitable as a rallying point for agreement on the ethical legitimacy of warfare. I first argue that self-defensive killing by a person X is morally justified if three conditions obtain: (1) X is together with at least one other person in a situation in which one of the persons will be killed through actions of the other person(s); (2) X is not responsible for bringing about that situation; (3) unless X kills another person, X him- or herself will be killed. Next, I show that on the basis of this principle military operations are morally justified only if there are no alternatives to executing them that would save more lives or prevent the total loss of freedom for people. The paper concludes with the observation that the morality of individual self-defensive killing is unable to justify most of current national defence policies.