Two experiments investigated the role of lithium-mediated environmental conditioning on instrumental performance. Experiment 1 demonstrated that a novel taste consumed in one arm of a T maze prior to lithium-induced toxicosis reduced performance in this environment whereas similar aversions conditioned in the home cage failed to alter maze performance. Experiment 2 showed that maze performance in a straight alleyway was decremented during extinction only in a group that actually traversed the alley prior to drinking saccharin and receiving lithium injections. This demonstrated that the instrumental decrement observed in Experiment 1 was due not only to the presence of an unpalatable flavor in the goalbox during the test.
Five-year-old children were tested for perceptual trading relations between a temporal cue (silence duration) and a spectral cue (F1 onset frequency) for the “say-stay” distinction. Identification functions were obtained for two synthetic “say-stay” continua, each containing systematic variations in the amount of silence following the /s/ noise. In one continuum, the vocalic portion had a lower F1 onset than in the other continuum. Children showed a smaller trading relation than has been found with adults. They did not differ from adults, however, in their perception of an “ay-day” continuum formed by varying F1 onset frequency only. The results of a discrimination task in which the two acoustic cues were made to “cooperate” or “conflict” phonetically supported the notion of perceptual equivalence of the temporal and spectral cues along a single phonetic dimension. The results indicate that young children, like adults, perceptually integrate multiple cues to a speech contrast in a phonetically relevant manner, but that they may not give the same perceptual weights to the various cues as do adults. 相似文献
Phonetic segments are coarticulated in speech. Accordingly, the articulatory and acoustic properties of the speech signal during the time frame traditionally identified with a given phoneme are highly context-sensitive. For example, due to carryover coarticulation, the front tongue-tip position for HI results in more fronted tongue-body contact for a /g/ preceded by /l/ than for a /g/ preceded by /r/. Perception by mature listeners shows a complementary sensitivity—when a synthetic /da/-/ga/ continuum is preceded by either /al/ or /ar/, adults hear more /g/s following HI rather than Irl. That is, some of the fronting information in the temporal domain of the stop is perceptually attributed to /l/ (Mann, 1980). We replicated this finding and extended it to a signaldetection test of discrimination with adults, using triads of disyllables. Three equidistant items from a /da/-/ga/ continuum were used preceded by /al/ and /ar/. In the identification test, adults had identified item ga5 as “ga”, and dal as “da”, following both /al/ and /ar/, whereas they identified the crucial item d/ga3 predominantly as “ga” after /al/ but as “da” after /ar/. In the discrimination test, they discriminated d/ga3 from dal preceded by /al/ but not /ar/; compatibly, they discriminated d/ga3 readily from ga5 preceded by /ar/ but poorly preceded by /al/. We obtained similar results with 4-month-old infants. Following habituation to either ald/ga3 or ard/ga3, infants heard either the corresponding ga5 or dal disyllable. As predicted, the infants discrimi-nated d/ga3 from dal following /al/ but not /ar/; conversely, they discriminated d/ga3 from ga5 following /ar/ but not /al/. The results suggest that prelinguistic infants disentangle consonant-consonant coarticulatory influences in speech in an adult-like fashion. 相似文献
The widespread use of seclusion and restraint in child psychiatric hospitals to manage aggression and noncompliance is based on the assumption that coercive consequences reduce the frequency of undesirable behaviors exhibited by the patients. We report a study of the use of seclusion and restraint in a public child psychiatric hospital during a 3-year period. Twenty-eight percent of the patients had been secluded or restrained a total of 1670 times. About 25% of these patients had been secluded more than five times during their hospitalization, and 32% had been placed in restraints more than once. Behaviors that typically resulted in repeated seclusion included physical aggression toward staff, verbal aggression toward peers, non-compliant or oppositional behavior, and self-harm. Variables that predicted patients most at risk for repeated seclusion included age, gender, and psychiatric diagnosis. The predictor variables for those most at risk for repeated restraint included age, property destruction, and self-harm. The high rates of use of seclusion and restraint suggest that these methods for controlling the behavior of children and adolescents in this child psychiatric hospital may not have been therapeutic. We suggest that staff in such hospitals engage in a pattern of behavior characterized by an aggression-coercion cycle, in which increasingly aggressive and coercive behaviors are exhibited by both patients and staff. 相似文献
This study was concerned with the qualitative differences in the male and female sex-trait stereotypes. Previous research employing the item pool of the Adjective Check List (ACL) had indicated no relationship between the stereotype loading of the adjectives and their favorability ratings. In the present study, university students rated the ACL items for strength and activity, and these ratings were used to demonstrate that the male stereotype was appreciably stronger and more active than the female stereotype. It was found that the strength ratings were highly correlated with both activity and favorability ratings which were, themselves, unrelated. It was concluded that the principal qualitative difference between the stereotypes lay in the connotations of activity and passivity associated, respectively, with the male and female stereotype traits, and that any assertion of greater social desirability for the male stereotype was based on its greater activity and not, as is often supposed, on its greater favorability. 相似文献
In a series of experiments, the ability of a single lithium preexposure to disrupt CS effectiveness was assessed using a latent inhibition procedure. Lithium preexposure administered proximal (90 min) to a saccharin familiarization trial reduced latent inhibition whereas a similar administration more distal (360 min) to flavor familiarization failed to do so. Additional experiments demonstrated that this socalled “US overshadowing” effect was not attributable to sensitization (Experiment 2), excitatory backward conditioning (Experiment 3), or state dependency (Experiment 4). The implications of US overshadowing for proximal US-preexposure effects are discussed. 相似文献