Components of attentional set-switching

A series of distinct event-related potentials (ERPs) have been recorded from the scalp of human subjects as they switch from one task to another. It is possible that task switching may depend on different mechanisms depending on whether the switch requires a change in attentional set, in other words the redirecting of attention to different aspects of a sensory stimulus, or whether it requires a change in intentional set, in others words a change in the way that responses are selected. To address this issue, the current study recorded ERPs while subjects switched between attentional sets and the results were compared with those of a previous investigation in which subjects switched between intentional sets. Subjects selected stimuli according to two conflicting attentional sets, each emphasizing one visual stimulus dimension (colour, shape). Pairs of stimuli, only one of which was to be attended, were presented for between eight and seventeen trials then either a switch or a stay cue was shown. The switch cue instructed subjects to switch from the current attentional set to the other set, while the stay cue instructed subjects to maintain the current set. Comparing ERPs time-locked to the switch and stay cues revealed neural correlates of the initiation of a task switch. Comparing the ERPs time locked to the first stimuli after either stay or switch cues identified neural correlates of the implementation of a task switch. A similar modulation over parietal electrodes was seen when subjects were switching between either attentional or intentional sets. While an intentional set switch began with a medial frontal modulation, attentional set switching began with a lateral frontal modulation. Implementing a new attentional set was associated with modulation of relatively early visual potentials, while implementing a new intentional set was associated with modulation of later response-related potentials. The results confirm that task switching consists of a number of constituent processes which may be taxed to different degrees depending on whether a task-switch paradigm requires subjects to change the way in which they select stimuli or responses.     

Predicting Divorce among Newlyweds from the First Three Minutes of a Marital Conflict Discussion

This study tested the hypothesis that how a discussion of a marital conflict begins--in its first few minutes--is a predictor of divorce. The marital conflict discussion of 124 newlywed couples was coded using the Specific Affect Coding System, and the data were divided into positive, negative, and positive-minus-negative affect totals for five 3-minute intervals. It was possible to predict marital outcome over a 6-year period using just the first 3 minutes of data for both husbands and wives. For husbands this prediction improved as the groups diverged in the remaining 12 minutes; for wives the prediction remained equally powerful for the remaining 12 minutes as it had been in the first 3 minutes.     

Oral dyspraxia in inherited speech and language impairment and acquired dysphasia

Half of the members of the KE family suffer from an inherited verbal dyspraxia. The affected members of the family have a lasting impairment in phonology and syntax. They were given various tests of oral praxis to investigate whether their deficit extends to nonverbal movements. Performance was compared to adult patients with acquired nonfluent dysphasia, those with comparable right-hemisphere lesions, and age-matched controls. Affected family members and patients with nonfluent dysphasia were impaired overall at performing oral movements, particularly combinations of movements. It is concluded that affected members of the KE family resemble patients with acquired dysphasia in having difficulties with oral praxis and that speech and language problems of affected family members arise from a lower level disorder.     

Pitch and timing abilities in inherited speech and language impairment

Members of the KE family who suffer from an inherited developmental speech-and-language disorder and normal, age-matched, controls were tested on musical abilities, including perception and production of pitch and rhythm. Affected family members were not deficient in either the perception or production of pitch, whether this involved either single notes or familiar melodies. However, they were deficient in both the perception and production of rhythm in both vocal and manual modalities. It is concluded that intonation abilities are not impaired in the affected family members, whereas their timing abilities are impaired. Neither their linguistic nor oral praxic deficits can be at the root of their impairment in timing; rather, the reverse may be true.     

Pitch and timing abilities in adult left-hemisphere-dysphasic and right-hemisphere-damaged subjects

The production and perception of pitch and rhythm were tested in patients with acquired unilateral left-hemisphere (LH) lesions (and subsequent motor dysphasia, n = 13), patients with unilateral right-hemisphere (RH) lesions (n = 14), and normal age-matched controls. While the LH dysphasic subjects were not generally impaired on the production or perception of pitch, they were grossly impaired on the production and perception of rhythm. The RH subjects, in contrast, were impaired on measures of pitch perception and production, including the discrimination and production of single notes and of melodies. It is concluded that the two hemispheres differ in their specialization for the perception and production of pitch and rhythm.     

Visibility distances with halogen and conventional headlights

Abstract.— Using visibility distance as a criterion, halogen and conventional continental European high and low-beam headlights were compared in a series of field experiments. On high-beam without opposing light the halogen headlights offered about 25% longer visibility distances than the conventional headlights. With both opposing cars using low-beam there was a slight advantage (<5 m) in favour of halogen headlights. The optimal dipping distance was a function of high-beam system (intensity) rather than low-beam system. Small differences in aiming, atmosphere etc. caused larger differences in visibility distance than did the headlight system.