Establishing a normal peer as a behavioral model for developmentally delayed toddlers.

The present investigation demonstrated a systematic teaching procedure for establishing a normal toddler as a peer-model for three children showing delayed development, each one under 27 mo. of age. For each delayed subject, training consisted of adult-directed prompting and social reinforcement contingent upon the delayed children's imitations of material use and motor responses emitted by a normal peer. Within-subjects multiple-baseline designs across responses were used to demonstrate intrasubject control over imitative responding. Indices of stimulus and response generalization were assessed through having the peer-model present the trained responses along with untrained responses in a situation free of adult prompting and social reinforcement for imitative responding. Results indicated that the training in peer-imitation was successful for establishing the peer-model's behavior in a stimulus control relationship with the imitative responding of the delayed children. Moreover, the findings generally demonstrated transfer of training across stimulus situations and responses. Implications for educational programming with developmentally delayed children are discussed.     

Naive misconceptions of Cooke and Breedin’s research: response to Ranney

In this paper, we respond to Ranney's (1994) comment on our paper on naive physics (Cooke & Breedin, 1994). In his comment, Ranney criticizes our methods and analyses, as well as our claims of theoretical inconsistency. In response to Ranney, we show that mast of his criticisms can be traced to several misconceptions. Some of these misconceptions seem to stem from his drawing of inappropriate similarities between his own research and ours. Specifically, ftanney seems to hall faun' misconceptions about our research: (1) the belief that trajectory responses in our study were relevant to our claims about theoretical consistency, (2) tie belief that aggregation of theoretical variations weakens claims of inconsistency, (3) the belief that the method of written reports is inferior to the method of structured interviews, and (4) the belief that our proposal of on-the-fly theorizing is at odds with temporal consistency and nonimpetus beliefs.     

Team cognition in experienced command-and-control teams

Team cognition in experienced command-and-control teams is examined in an UAV (Uninhabited Aerial Vehicle) simulation. Five 3-person teams with experience working together in a command-and-control setting were compared to 10 inexperienced teams. Each team participated in five 40-min missions of a simulation in which interdependent team members control a UAV to take reconnaissance photos. Experienced teams exceeded performance of inexperienced teams, suggesting transfer of previous command-and-control experience. Compared to inexperienced teams, experienced teams had fewer errors on process-related training knowledge, superior team process ratings, and communications containing fewer coordination-related utterances. These findings support the view that team cognition emerges through the interactions of team members, that interactions distinguish high-performing teams from average teams, and that these interactions transfer across different tasks.     

Cross-national differences in the assessment of psychopathy: do they reflect variations in raters' perceptions of symptoms?

Cross-national differences in the prevalence of psychopathy have been reported. This study examined whether rater effects could account for these differences. Psychopathy was assessed with the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991). Videotapes of 6 Scottish prisoners and 6 Canadian prisoners were rated by 10 Scottish and 10 Canadian raters. No significant main or interaction effects involving the nationality of raters were detected at the level of full scores or factor scores. Using a generalizability theory approach, it was demonstrated that the interrater reliability of total scores was good, that is, the proportion of variance in test scores attributable to raters was small. The interrater reliability of factor scores was lower, typically falling in the fair range. Overall, the results suggest that the reported cross-national differences are more likely to be in the expression of the disorder rather than in the eye of the beholder.     

Cooling blocks ITM and LTM formation and preserves memory

In Lymnaea aerial respiratory behaviour can be operantly conditioned; snails learn not to perform this behaviour. Depending on the training procedure used, snails are competent to form either intermediate-term (ITM; lasting 1-3 h) or long-term (LTM; >4 h) memory. We found that cooling the snails for 1 h immediately after training was sufficient to block either ITM or LTM. Cooling snails for a similar period 10 or 15 min after cessation of training, failed to block ITM and LTM formation, respectively. Finally, we employed the cooling technique to extend both ITM and LTM. That is, cooling could prevent forgetting. Cooling extended LTM that normally persisted for 2 days to at least 8 days. These data are consistent with the hypothesis that forgetting is due to the learning and remembering of interfering events, and thus is an active process.     

Rapid Error Correction During Human Arm Movements

Studies were made of rapid error correction movements in eight subjects performing a visually guided tracking task involving flexion-extension movements about the elbow. Subjects were required to minimize reaction times in this two-choice task. Errors in initial movement direction occurred in about 3% of the trials. Error correction times (time from initiation to reversal of movement in incorrect direction) ranged from 30-150 ms. The first sign of correction of the error movement was a suppression of the electromyographic (EMG) activity in the muscle producing the error movement. This suppression started as early as 20-40 ms after the initiation of the error-related EMG activity and as much as 50 ms before any overt sign of limb movement. The correction of the error movement was also accompanied by an increase in the drive to the muscle which moved the arm in the correct direction. This increased activity always occurred after the initiation of the error movement. It is concluded that the first step in the error correction, suppression of drive to the muscle producing the error movement, cannot be based on information from the moving limb. It is thus suggested that this earliest response to the error movement is based on central monitoring of the commands for movement.     

Eating for pleasure or profit: the effect of incentives on children's enjoyment of vegetables

Parents commonly use rewards to encourage children to eat healthfully, but this practice remains controversial because rewards are suspected of undermining children's intrinsic motivation. A cluster-randomized trial examined children's acceptance of a disliked vegetable over 12 daily taste exposures. These exposures were paired with a tangible reward, a social reward, or no reward, and the findings were compared with the results from a no-treatment control condition. Liking and intake of the vegetable were assessed in a free-choice consumption task at preintervention, postintervention, 1 month after intervention, and 3 months after intervention. Liking increased more in the three intervention conditions than in the control condition, and there were no significant differences between the intervention conditions. These effects were maintained at follow-up. Children in both reward conditions increased consumption, and these effects were maintained for 3 months; however, the effects of exposure with no reward became nonsignificant by 3 months. These results indicate that external rewards do not necessarily produce negative effects and may be useful in promoting healthful eating.