植入前遗传学诊断中性别选择的伦理辩护

植入前遗传学诊断（PGD）是在胚胎植入子宫前进行遗传学检查的新技术。它可对植入胚胎进行性别选择,从而引发了会增加我国出生人口性别比的担忧。通过对PGD性别选择伦理风险的分析,指出其用于医学需要时不会对性别比造成危害。但在实施过程中需要医生、患者及社会全体人员共同参与,避免该技术用于非医学目的的需要。     

Repeated cocaine experience facilitates sucrose-reinforced operant responding in enriched and isolated rats

The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30) prior to and after 10 days of exposure to cocaine (15 mg/kg, i.p.) or saline was compared. Regardless of rearing condition, rats repeatedly exposed to cocaine had shorter reacquisition latencies to complete a sucrose-reinforced FR 30 task than saline controls. The results suggest that cocaine exposure may have cross-sensitized both EC and IC rats to the reinforcing effects of sucrose or sucrose-associated cues, thus facilitating reacquisition of operant responding.     

Perceptions of female body weight and shape among indigenous and urban Europeans

Two important cues to female physical attractiveness are body mass index (BMI) and body shape as measured by the waist-to-hip ratio (WHR). This study examined the relative contribution of both cues in three culturally distinct populations. A total of 119 Finnish, Sámi and British male observers rated a set of un-edited photographs of women with known BMI and WHR. The results showed that there were significant differences in preferences for physical attractiveness, with the indigenous Sámi preferring figures with larger BMIs and more tolerant of heavyweight figures than either Finnish participants in Helsinki or Britons in London, who were indistinguishable in their preferences for slim figures. The findings are discussed in terms of evolutionary psychological explanations of mate selection, and sociocultural theories which emphasizes the learning of preferences for body sizes in social and cultural contexts.     

Trustworthiness,friendships and self‐control: factors that contribute to young children's school adjustment

The aim of present study was to examine the relationship between young children's peer‐reported trustworthiness and their school adjustment. Two hundred and eleven (103 male and 108 female) children in the United Kingdom (mean age = 6 years 2 months) took part in this study. Measures of peer‐reported trustworthiness, child‐rated school adjustment, and teacher‐rated school adjustment were administered twice across a one‐year period. Also, children's number of friendships, peer acceptance, and self‐control were assessed at Time 2. Multisample path analyses were conducted separately by sex. For both samples there were direct longitudinal paths between peer‐reported trustworthiness and changes in teacher‐rated school adjustment. For boys, the longitudinal path between peer‐reported trustworthiness and changes in child‐rated loneliness was mediated by peer acceptance, and peer‐reported trustworthiness mediated the relationship between self‐control and teacher‐rated school adjustment. Sex differences in peer‐reported trustworthiness also emerged: girls were rated as more trustworthy by their peers than were boys. The findings support the hypothesis that young children's trustworthiness contributes to school adjustment, which is due in part to peer acceptance. Copyright © 2007 John Wiley & Sons, Ltd.     

Physical aggression as a function of perceived fighting ability among male and female prisoners

Study 1 used two scenarios depicting provocations to investigate whether prisoners' willingness to engage in physical aggression would vary according to the perceived fighting ability (Resource Holding Power [RHP]) of the opponent. RHP was operationalized in terms of three levels of the size, number of allies, and reputation. The sample (both sexes; N=1,253) was taken from a range of British prisons. Unexpectedly, the prisoners said that they would be less likely to attack a weaker opponent than an equally matched one. The predicted decline from equally matched to more formidable opponents was found only under some conditions. A further sample of male prisoners (N=260), completed a similar provocation scenario, with response options covering fear, several forms of aggression, the importance of the provocation for reputation, and that the provocation was unimportant. Fear increased with RHP as predicted. Lower physical aggression to a low RHP opponent was again found, and it was associated with a lesser impact on reputation of an insult from this source. There was also a lower likelihood of responding with physical aggression to a high RHP opponent, as originally predicted. Implications of the findings for motivational theories of aggression are discussed, and also the applicability to humans of concepts from game theory models of the evolution of fighting strategies.     

Officer attitudes towards adult male prisoners who self-harm: development of an attitudinal measure and investigation of sex differences

Purpose: The aim of the current study was to explore attitudes towards self‐harm in a sample of prison officers, with subsidiary aims of assessing if these attitudes alter as a function of the prisoner's behavior and the sex of the participant. Method: One hundred and sixty‐two officers (100 men and 62 women) completed a general measure of their attitudes towards prisoners and one designed to assess Attitudes towards Prisoners who Self‐Harm (APSH). Participants rated their perceptions of two adult male prisoners depicted in vignettes. The vignettes depicted identical types of self‐harm but varied the behavioral characteristics of the prisoners involved, with one depicted as “well‐behaved” and the other as “disruptive”. Results: Women were more likely than men to report positive attitudes towards self‐harm and in particular were less likely than men to endorse negative myths regarding self‐harm. The prisoner depicted as “disruptive” invoked increased negative attitudes than the “well‐behaved” prisoner. This finding was consistent across sex. Conclusion: The current study indicates that APSH are comprised of a number of components that were influenced by the sex of the participant and the behavioral characteristics of the prisoners depicted. The implications of these findings to practice are discussed. Aggr. Behav. 33:63–72, 2007. © 2006 Wiley‐Liss, Inc.     

Waist-to-Hip Ratio and Unhealthy Body Change in Women

The role of waist-to-hip ratio (WHR) in unhealthy body change was examined in a sample of 143 women university students. They completed the Eating Disorder Examination-Questionnaire (EDE-Q), reported their level of concern with weight and with WHR, and used unmarked measuring tapes to record their subjective (self-perceived), ideal, and objective (measured) waist and hip circumference. Although body shape was reported as important, and concern with WHR correlated significantly with symptoms of disordered eating, the relationships involving WHR were not independent of those involving body weight. Thus, there appears to be little behavioural and/or clinical significance in the aesthetic evaluations made by women of their WHR. Reasons for this are considered in light of evidence that women regard WHR as more difficult to control and less amenable to change than their overall body weight.     

Bouts of responding: the relation between bout rate and the rate of variable-interval reinforcement

By nose poking a lighted key, rats obtained food pellets on either a variable-interval schedule of reinforcement or a schedule that required an average of four additional responses after the end of tile variable-interval component (a tandem variable-interval variable-ratio 4 schedule). With both schedule types, the mean variable interval was varied between blocks of sessions from 16 min to 0.25 min. Total rate of key poking increased similarly as a function of the reinforcer rate for the two schedule types, but response rate was higher with than without the four-response requirement. Analysis of log survivor plots of interresponse times showed that key poking occurred in bouts. The rate of initiating bouts increased as a function of reinforcer rate but was either unaffected or was decreased by adding the four-response requirement. Within-bout response rate was insensitive to reinforcer rate and only inconsistently affected by the four-response requirement. For both kinds of schedule, the ratio of bout time to between-bout pause time was approximately a power function of reinforcer rate, with exponents above and below 1.0.     

Unit price and choice in a token-reinforcement context

Pigeons were exposed to multiple and concurrent second-order schedules of token reinforcement, with stimulus lights serving as token reinforcers. Tokens were produced and exchanged for food according to various fixed-ratio schedules, yielding equal and unequal unit prices (responses per unit food delivery). On one schedule (termed the standard schedule), the unit price was held constant across conditions. On a second schedule (the alternative schedule), the unit price was either the same or different from the standard. Under conditions with unequal unit prices, near-exclusive preference for the lower unit price was obtained. Under conditions with equal unit prices, the direction and degree of preference depended on ratio size (number of responses per exchange period). When this ratio differed, strong preferences for the smaller ratio were observed. When this ratio was equal, preferences were nearer indifference. Response rates on the multiple schedule were generally consistent with the preference data in showing sensitivity to ratio size. Results are discussed in terms of a unit-price model that includes handling and reinforcer immediacy as additional costs. On the whole, results show that preferences were determined primarily by delay to the exchange period.     

Assessment of deviant arousal in adult male sex offenders with developmental disabilities

Ten individuals, residing in a treatment facility specializing in the rehabilitation of sex offenders with developmental disabilities, participated in an arousal assessment involving the use of the penile plethysmograph. The arousal assessments involved measuring change in penile circumference to various categories of stimuli both appropriate (adult men and women) and inappropriate (e.g., 8- to 9-year-old boys and girls). This approach extends the existing assessment literature by the use of repeated measurement and single-subject experimental design. Data from these assessments were analyzed to determine if clear and informative outcomes were obtained. Overall, three general patterns of results emerged. Some participants showed differentiated deviant arousal or higher levels of arousal to specific inappropriate stimuli (deviant is a term used in the existing sex-offender literature to describe this type of arousal). Other participants showed undifferentiated deviant arousal, in which case they showed nonspecific arousal to inappropriate stimuli. The remaining participants showed no arousal to inappropriate stimuli but did show arousal to appropriate stimuli. Implications for assessment, treatment, and future directions are discussed.