Developmental priority of identity conservation: acceleration of identity and equivalence in normal and moderately retarded children

In an attempt to clarify the chronological relationship between identity and equivalence conservation, normal preschool-aged children (experiment 1) were exposed to brief videotape demonstrations of a model conserving identity and equivalence, identity only, equivalence only, or neither. Subsequent performances indicate that identity was easier to accelerate than equivalence, and training in both identity and equivalence appeared to be most effective in accelerating conservation. Trainable mentally retarded (TMR) children were then exposed to either the identity-equivalence-conserving or control model (experiment 2). This population, which some have argued remains at a preoperational level of functioning, was more likely to conserve identity than equivalence. In addition, conservation in the training group increased following training, though these gains were not maintained over a 3-week retention interval.     

The effects of extraneous speech on visual vigilance performance of children

First-grade males performed a 30-min visual vigilance task under 5 conditions of auditory background stimulation. The 5 conditions consisted of (1) continuous conversation, in which subjects listened to a tape of conversation spliced so that there were no intervals of silence lasting longer than 3 sec; (2) continuous reverse, in which subjects heard the continuous conversation tape played in reverse; (3) intermittent conversation, in which subjects heard alternating segments of conversation and silence; (4) intermittent reverse, in which subjects heard alternating segments of reverse conversation and silence; and (5) silence control. Compared with silence or continuous stimulation, intermittent stimulation produced better detection regardless of whether or not it was meaningful. High achievers made more correct detections than low achievers, but only in the second and third time periods. Few subjects made errors of commission.     

The effects of provocation, intentions, and consequences on children's moral judgments.

Dutch boys 8 and 12 years old read brief stories about a harm doer whose intentions were either good or bad and whose actions resulted in either minor or serious injury to a victim. The harm doer had previously been either strongly provoked or not provoked by the victim. The older boys differentiated their evaluations of the harm doer's naughtiness on the basis of provocation and intentions, while the younger boys failed to differentiate their evaluations of the provoked harm doer on the basis of intentions. Both age groups strongly differentiated their judgments of the victim's naughtiness on the basis of his role as provoker, except when the victim was seriously injured by a bad-intentioned aggressor.