Dominance and age-related changes in the play fighting of intact and post-weaning castrated male rats (Rattus norvegicus)

The play fighting behaviour of male rats (Rattus norvegicus) castrated at weaning was compared to that of intact controls during the juvenile and post-pubertal phases of development. Following puberty, both the castrated and intact animals exhibited an age-related change in their play fighting; the frequency of initiating play fighting decreased and juvenile patterns of playful defense were replaced by more adult-like patterns. As these changes occurred even in the absence of the pubertal surge of gonadal hormones, they were more likely to result from the organizational effects of gonadal hormones in the perinatal period than the activational effects of these hormones at puberty. Although the castrated animals exhibited the age-related changes in behaviour, they did not exhibit the asymmetries in play associated with dominance relationships. As demonstrated in previous studies, in pairs of intact rats, the animal that attacks the most and uses more juvenile defenses during play fighting and weighs the least is typically the subordinate. In the castrates, asymmetries in weight and playful defense are not related to play frequency, indicating the absence of a dominance relationship. Although the characteristic changes in male play fighting at puberty are independent of the activational effects of gonadal hormones, dominance relationships and their associated changes in play fighting are dependent on these hormones. Therefore, in the perinatal period gonadal hormones most likely organize the age-related changes in play behaviour, whereas post-pubertally gonadal hormones activate dominance relationships and thus, indirectly modify play fighting by affecting dominance-associated assymetries in behaviour. © 1996 Wiley-Liss, Inc.     

Family communication styles, attitude towards institutional authority and adolescents' violent behaviour at school

The purpose of present study is to analyse the relationship among certain family and school factors, adolescents' attitude towards institutional authority, and violent behaviour at school. The sample is composed of 1049 adolescents of both sexes and aged from 11 to 16 years old. Statistical analyses were carried out using structural equation modelling. Results indicate a close association between negative communication with father and violent behaviour in adolescence. Moreover, data suggest that teachers' expectations affect students' attitude towards institutional authority, which in turn is closely related to school violence. Finally, findings show an indirect influence of father, mother and teacher in adolescents' violent behaviour, mainly through their effect on family- and school-self-concept.     

Individual and social risk factors related to overt victimization in a sample of Spanish adolescents

This study analyzes the role of adolescents' self-esteem, loneliness, sociometric status, and perceptions of family and classroom environment on overt vicitimization by peers in a sample of 1319 Spanish adolescents (48% boys and 52% girls), ages 11 to 16 years (M=13.7, SD=1.5). The findings from structural equation modeling suggest that adolescents' self-esteem, loneliness, and sociometric status had a significant direct effect on overt victimization by peers, and adolescents' perceptions of family and classroom environment had a significant indirect effect on peer overt victimization mediated by self-esteem, loneliness, and sociometric status. The findings are discussed with the consideration of these variables as individual and social risk factors for overt victimization by peers.     

Possible participation of D3 and D4 dopaminergic receptors on genital reflexes induced by cocaine in paradoxical sleep deprived male rats

Previous studies have demonstrated that paradoxical sleep deprivation (PSD) potentiates cocaine-induced genital reflexes in male rats and both D1 and D2 receptors may play a role in those effects, and to examine the possibility that such might involve other dopaminergic receptors, we investigated the effects of D3 and D4 receptor subtype antagonists on cocaine-induced reflexes in sleep-deprived rats. Separate groups of PSD rats received saline, D3 (U9919A; 0.75, 1.5 and 3 mg/kg) or D4 (L745870; 0.75, 1.5 and 3 mg/kg) antagonists prior to acute cocaine challenge. Results demonstrated that U9919A induced significant reduction in the number of animals that displayed erection and the frequency of erection at two smaller doses, while no significant difference was reported for the D4 receptor antagonist. Although our studies indicate that there is a relevant participation of D3 receptors in male sexual function, D4 receptors seem not to exert an essential role in this model.     

Behavioural evidence for separating components within visuo-spatial working memory

Several different sources of evidence support the idea that visuo-spatial working memory can be segregated into separate cognitive subsystems. However, the nature of these systems remains unclear. Recently we reported data from neurological patients suggesting that information about visual appearance is retained in a different subsystem from information about spatial location. In this paper we report latency data from neurologically intact participants showing an experimental double dissociation between memory for appearance and memory for location. This was achieved by use of a selective dual task interference technique. This pattern provides evidence supporting the segregation of visuo-spatial memory between two systems, one of which supports memory for stimulus appearance and the other which supports memory for spatial location.     

Investigating mental representation of order with a speeded probed recall task

We compare three models of representation of item order in a verbal STM task: item-item associations, item-position associations, and primacy gradient. A speeded probed recall task is used, in which a list of words is presented, immediately followed by a probe; participants must report as fast as possible the word that was in the probed position. In the number probe condition, a digit is presented and one must say the word in that position. In the word probe condition, the probe is an item of the list and participants must say the immediately following item. Response times (RTs) are analyzed according to probe type and position. The three models imply different predictions about RTs as a function of serial order in the two conditions. Our results suggest a serial, self-terminating search from the beginning of the list to the target position, except for the final position, which is directly accessible. The item-item and item-position association models are ruled out; the primacy gradient model accounts satisfactorily for our results, except for the finding of a larger recency effect with a number probe. Alternative interpretations are also discussed.     

Mainstream Economics and Sense-Making

This work presents a semiotic approach to the economy, underlining that any economic phenomena is at the same time a communicative act as it is contingent to sense-making.The article discusses this topic by focusing on a specific phenomenon studied by economics: the underground economy. It shows that the conceptualization of the underground economy in terms of sense-making processes offers a thought-provoking perspective for theoretical development. More in general, the discussion proposed makes it clear that in order to deepen our vision of economic phenomena in a more thoughtful and realistic way we need to rethink these phenomena as being reciprocally and circularly embedded in the semiotic flow of life. The economy is within sense-making and it is shaped by it; at the same time sense-making is within the economy, as its semiotic substance.

Vocabulary learning in primary school children: Working memory and long-term memory components

The goal of this study was to investigate which working memory and long-term memory components predict vocabulary learning. We used a nonword learning paradigm in which 8- to 10-year-olds learned picture-nonword pairs. The nonwords varied in length (two vs. four syllables) and phonology (native sounding vs. including one Russian phoneme). Short, phonologically native nonwords were learned best, whereas learning long nonwords leveled off after a few presentation cycles. Linear structural equation analyses showed an influence of three constructs—phonological sensitivity, vocabulary knowledge, and central attentional resources (M capacity)—on nonword learning, but the extent of their contributions depended on specific characteristics of the nonwords to be learned. Phonological sensitivity predicted learning of all nonword types except short native nonwords, vocabulary predicted learning of only short native nonwords, and M capacity predicted learning of short nonwords but not long nonwords. The discussion considers three learning processes—effortful activation of phonological representations, lexical mediation, and passive associative learning—that use different cognitive resources and could be involved in learning different nonword types.     

Early alternative derivations of Fechner's law

Historians of psychology, notably Boring, fostered Fechner's idea that Weber's law is the indispensable basis for the derivation of the logarithmic psychophysical law. However, it is shown here that Bernoulli in 1738 and Thurstone in 1931 derived the logarithmic law using principles other than Weber's law and that Fechner and Thurstone based their derivations on the principles originally employed by Bernoulli. It is concluded that awareness of researchers about Bernoulli's and Thurstone's derivations could expand the directions of research on the form of the psychophysical law. © 2009 Wiley Periodicals, Inc.     

Identification of the possible origin of the body target that differentiates play fighting from serious fighting in syrian golden hamsters (Mesocricetus auratus)

Play fighting in the Syrian Golden hamster Mesocricetus auratus can be distinguished from serious fighting by the targets attacked in each case. In play fighting, the animals attack and defend the cheeks and cheek pouches, whereas in serious fighting they attack and defend the rump and lower flanks. Since play typically involves the use of behaviors borrowed from other functional contexts, this paper investigates the origin of the cheek target during play fighting. Comparison of resident-intruder serious fighting with awake and anesthetized intruders does not reveal the cheek to be an inhibited target for serious attack. Similarly, analysis of social investigation and allog-rooming, while revealing the ears to be important targets, do not show the cheeks to be targets in these behaviors. Sniffing, licking, and nibbling of the cheek area appear to occur mainly during sexual encounters by males. This area, seemingly a sexual target, may be the one utilized during play fighting.