Matching-to-sample accuracy on fixed-ratio schedules.

Pigeons performing on a matching-to-sample procedure were exposed to six fixed-ratio (FR) schedules (FR 1, 5, 10, 20, 40, and 60) of food reinforcement for correct matching responses. During both a correction and a noncorrection procedure without an intertrial interval (ITI), matching accuracy was lower on FR 1 and FR 60 than at intermediate ratios. With the FR 1 schedule, both a 5-sec and a 25-sec ITI resulted in higher matching accuracy than without an ITI; accuracy, with an ITI, was fairly constant for ratios of 1 to 20 but declined at higher ratios. The results suggest that the presence or absence of an ITI in matching to sample may account for inconsistencies obtained in earlier studies of the relationship of matching accuracy to ratio size.     

A comparison of self-instructional checking procedures for remediating mathematical deficits

We examined the relative effectiveness of three procedures for teaching long multiplication/division to seven adolescents with learning disabilities: no-checking, end-checking, and multi-checking. During training, each subject was taught by modelling and imitation to verbalize self-instructions in the form of a strategy while solving the problems. The relative effects of the checking and no-checking procedures on accuracy and rate of problems completed were examined in an alternating treatments design. The best treatment was then given alone and a reversal was implemented six weeks later, followed by a return to the best treatment during a final phase. Irrespective of the procedure used, the subjects' accuracy improved while the rate of problems completed decreased. These effects were greatest with the multi-checking procedure for six of the seven subjects. Generalization to untaught problems of various levels of complexity occurred under all procedures. Though maintenance effects were seen during the follow-up, accuracy was generally higher and more reliable when the subject's best checking procedure was reinstated. It is suggested that error detection and correction were important for maintaining high levels of accuracy and that these operated differentially in the three procedures to produce the differing levels of accuracy. The role of other factors such as pre-skill knowledge, complexity of the problem and prior reinforcement history are also considered.     

On the Bock-Aitkin procedure—From an EM algorithm perspective

The relationship between the EM algorithm and the Bock-Aitkin procedure is described with a continuous distribution of ability (latent trait) from an EM-algorithm perspective. Previous work has been restricted to the discrete case from a probit-analysis perspective. The author is grateful to Bradley A. Hanson for valuable discussion and comments. Thanks also go to Terry A. Ackerman, Meichu Fan, Subrata Kundu, and Robert K. Tsutakawa for their help and encouragement in this study.     

安乐死立法比较兼立法原则理论初探

通过介绍与借鉴荷兰、美国、日本、比利时等国安乐死立法经验,结合我国立法难的现状,对我国安乐死立法进程进行思考,同时建设性提出了我国安乐死的立法原则:生命权神圣不可侵犯原则,死亡方式选择权有限制的自主决定原则,知情自愿原则,严格程序原则等。     

社区服刑人员心理健康状况调查

以探讨社区服刑人员的心理特点为目的,以康健街道社区服刑人员为范围,采用艾森克人格问卷(EPQ)及SCL-90症状自评量表对社区服刑人员的人格、心理健康方面进行调查。结果发现社区服刑人员在总体上虽基本属于正常人群在其人格特征仍与罪犯人群所特有的特点具有少量共性;其心理健康也普遍存在一定问题;同时,证明了社区服刑人员的人格与心理健康有一定的联系,其结果可以在今后的社区心理矫正工作中加以关注和应用。     

Initial excitatory conditioning with the truly random control procedure in rats: The effects of density of the conditioned stimulus

The present experiments were designed to test whether initial excitatory conditioning to a stimulus was obtained, using a within-subject design of the truly random control (TRC) procedure, and to examine the effects of the density of the conditioned stimulus on it. In Experiment 1, the effect of the three levels of CS density (50%, 25%, 20%) was assessed at six different stages of training, using the conditioned suppression of licking in rats. Although all of the groups given the TRC procedure showed evidence of initial excitatory conditioning, it was more marked in the group with the highest CS density than in the other groups. Experiment 2 confirmed the results of Experiment 1, using a between-subject design. The findings are in line with predictions from the Rescorla-Wagner model, and are discussed with reference to other contemporary theories of associative learning.     

Some effects of response-correlated increases in reinforcer magnitude on human behavior

After training under short or long fixed-interval schedules, humans responded under a modified fixed-interval schedule in which magnitude of reinforcement (X or 2X) was minimally correlated with response frequency. Response frequencies that equaled or exceeded a minimum response criterion were followed by the larger reinforcer at the end of the interval; otherwise, the smaller reinforcer was delivered. The modified schedule alternated with the baseline schedule across conditions. In a control condition, the reinforcer magnitudes produced by control subjects were yoked to those of experimental subjects. Experimental subjects, but not control subjects, showed increased responding. In addition to the baseline and modified fixed-interval schedules used in Experiment 1, subjects in Experiment 2 also responded under a second modified fixed-interval contingency in which increases in reinforcer magnitude were more highly correlated with response frequency. Experimental subjects, but not control subjects, showed increased responding under both procedures. Direct comparison of these two procedures showed that the high-correlation procedure produced greater increases in responding than did the low-correlation procedure.     

Gender differences in memory for objects and their locations: a study on automatic versus controlled encoding and retrieval contexts

Object-location memory is the only spatial task where female subjects have been shown to outperform males. This result is not consistent across all studies, and may be due to the combination of the multi-component structure of object location memory with the conditions under which different studies were done. Possible gender differences in object location memory and its component object identity memory were assessed in the present study. In order to disentangle these two components, an object location memory task (in which objects had to be relocated in daily environments), and a separate object identity recognition task were carried out. This study also focused on the conditions under which object locations were encoded and retrieved. Only half of the participants were aware of the fact that object locations had to be retrieved later on. Moreover, by applying the 'process dissociation procedure' to the object location memory assessments and the 'remember-know' paradigm to the object identity measure, the amount of explicit (conscious) and implicit (unconscious) retrieval was estimated for each component. In general, females performed better than males on the object location memory task. However, when controlled for object identity memory, females no longer outperformed males, whereas they did not obtain a higher general object identity memory score, nor did they have more explicit or implicit recollection of the object identities. These complicated effects might stem from a difference between males and females, in the way locations or associations between objects and locations are retrieved. In general, participants had more explicit (conscious) recollection than implicit (unconscious) recollection. No effect of encoding context was found, nor any interaction effect of gender, encoding and retrieval context.     

Evidence of blocking with geometric cues in a virtual watermaze

Three computer based experiments, testing human participants in a non-immersive virtual watermaze task, used a blocking design to assess whether two sets of geometric cues would compete in a manner described by associative models of learning. In stage 1, participants were required to discriminate between visually distinct platforms. In stage 2, additional spatial information was provided by the shape or the color of the walls of the pool. In a test trial, the platforms were removed and the spatial knowledge acquired regarding the position of the platform was assessed. Experimental groups were compared against control groups which did not receive stage 1 training. The unique color of the correct platform, in Experiments 1 and 3, disrupted learning about the colored walls but not the geometry of the pool. In Experiment 2, the correct platform was identifiable from its position within the three platform array. Learning the relative position of the correct platform within the array disrupted learning about its position relative to the geometry of the pool, but not to the colored walls. The results suggest that learning the position of a goal in relation to the geometry of the environment can be blocked but only by an alternative geometric cue.     

Intuition and The Junctures of Judgment in Decision Procedures for Clinical Ethics

Moral decision procedures such as principlism or casuistry require intuition at certain junctures, as when a principle seems indeterminate, or principles conflict, or we wonder which paradigm case is most relevantly similar to the instant case. However, intuitions are widely thought to lack epistemic justification, and many ethicists urge that such decision procedures dispense with intuition in favor of forms of reasoning that provide discursive justification. I argue that discursive justification does not eliminate or minimize the need for intuition, or constrain our intuitions. However, this is not a problem, for intuitions can be justified in easy or obvious cases, and decision procedures should be understood as heuristic devices for reaching judgments about harder cases that approximate the justified intuitions we would have about cases under ideal conditions, where hard cases become easy. Similarly, the forms of reasoning which provide discursive justification help decision procedures perform this heuristic function not by avoiding intuition, but by making such heuristics more accurate. Nonetheless, it is possible to demand too much justification; many clinical ethicists lack the time and philosophical training to reach the more elaborate levels of discursive justification. We should keep moral decision procedures simple and user-friendly so that they will provide what justification can be achieved under clinical conditions, rather than trying to maximize our epistemic justification out of an overstated concern about intuition.