Cooperative responding in rats maintained by fixed‐ and variable‐ratio schedules

The present study investigated the effects of fixed‐ratio (FR) and variable‐ratio (VR) reinforcement schedules on patterns of cooperative responding in pairs of rats. Experiment 1 arranged FR 1, FR 10, and VR 10 schedules to establish cooperative responding (water delivery depended on the joint responding of two rats). Cooperative response rates and proportions were higher under intermittent schedules than under continuous reinforcement. The FR 10 schedule generated a break‐and‐run pattern, whereas the VR 10 schedule generated a relatively high and constant rate pattern. Experiment 2 evaluated the effects of parametric manipulations of FR and VR schedules on cooperative responding. Rates and proportions of cooperative responding generally increased between ratio sizes of 1 and 5 but showed no consistent trend as the ratio increased from 5 to 10. Experiment 3 contrasted cooperative responding between an FR6 schedule and a yoked control schedule. Coordinated behavior occurred at a higher rate under the former schedule. The present study showed that external consequences and the schedules under which the delivery of these consequences are based, select patterns of coordinated behavior.     

The Effects of Scrambling on Spanish and Korean Agrammatic Interpretation: Why Linear Models Fail and Structural Models Survive

Several models of comprehension deficits in agrammatic aphasia rely heavily on linear considerations in the assignment of thematic roles to structural positions (e.g., the Trace-Deletion Hypothesis, the Mapping Hypothesis, and the Argument-Linking Hypothesis). These accounts predict that constructions in languages with rules that affect syntactic structure but preserve relative linear order should be unimpaired. Other models [e.g., the Double-Dependency Hypothesis, (DDH)] do not resort to linearity but are purely structural in conception and therefore should be immune to word-order effects. We tested linear and nonlinear accounts with scrambling structures in Korean and topicalization structures in Spanish. The results are very clear. The (nonlinear) DDH is entirely compatible with the evidence, but the linear accounts are not.     

The role of the amygdala in facial emotional expression during a discrimination task

A total of 50 patients with temporal lobe epilepsy with unilateral resection of the hippocampus and the amygdala were studied: --27 with left lobectomy (LTL group) and 23 with right lobectomy (RTL group)--; and 28 healthy control participants (HC group). The task consisted of identifying the dissimilar photograph from a group of photographs of the same face. The difference could correspond to the identity of the model or the facial expression (happiness, anger, sadness and fear). The results showed that when the difference in the photograph resided in the identity of the model, the RTL group made more mistakes than the HC group. When the facial expression was the distinguishing feature, mean response latency was longer in the LTL group than in the HC group. Comparison of the emotions revealed that the greatest differences were obtained with the fear expression, in all three participant groups. The dissociation of neural circuits responsible for processing facial expressions is discussed and, especially, the role of the left amygdala to discriminate between facial expressions.     

Illusion of control in Internet users and college students.

When people try to obtain a desired event and this outcome occurs independently of their behavior, they often think that they are controlling its occurrence. This is known as the illusion of control, and it is the basis for most superstitions and pseudosciences. However, most experiments demonstrating this effect had been conducted many years ago and almost always in the controlled environment of the psychology laboratory and with psychology students as subjects. Here, we explore the generality of this effect and show that it is still today a robust phenomenon that can be observed even in the context of a very simple computer program that users try to control (and believe that they are controlling) over the Internet. Understanding how robust and general this effect is, is a first step towards eradicating irrational and pseudoscientific thinking.     

THIS ARTICLE HAS BEEN RETRACTED: Enumeration of objects and substances in non‐human primates: experiments with brown lemurs (Eulemur fulvus)

Both human infants and adult non‐human primates share the capacity to track small numbers of objects across time and occlusion. The question now facing developmental and comparative psychologists is whether similar mechanisms give rise to this capacity across the two populations. Here, we explore whether non‐human primates’ object tracking abilities are subject to the same constraints as those of human infants. In particular, we examine whether one primate species, the brown lemur (Eulemur fulvus), also fails to represent and enumerate objects when they behave non‐rigidly or non‐cohesively. We presented lemurs with a series of expectancy violation studies involving simple 1 + 1 addition events in which we varied the entities to be enumerated. Like infants, lemurs successfully enumerated the two objects when those objects were rigid, cohesive individuals, but failed to enumerate similar‐looking non‐rigid piles of sand. In contrast to human infants, however, lemurs successfully enumerated non‐cohesive objects that broke into multiple pieces. These results are discussed in light of recent theories about object processing in human infants and adults.     

Attentional bias for doping words and its relation with physical self-esteem in young adolescents

ObjectivesPrevious studies revealed that adolescence is a period of risk for doping and drug addiction and that young athletes who used doping agents reported low self-esteem. We conducted a preventive study with the aims to investigate whether young adolescents displayed an attentional bias to doping-related words and whether this attentional bias was related to physical self-esteem.MethodNinety seven adolescents (44 girls and 53 boys) from 11 to 15 years-old participated to a study designed to measure reaction times (RT) in a Stroop emotional task related to doping, cheating and control words. They also completed the Physical Self-Perception Profile subscales assessing perceived general self-esteem, physical self-worth, physical condition, sport competence, body attractiveness, and physical strength.ResultsParticipants exhibited longer RT after doping words than after control words. RT was also longer after doping than after cheating words. Participants belonging to the low physical self-esteem group exhibited larger carry-over effects than those who were in the high physical self-esteem group.ConclusionsThese findings suggest that attentional resources allocated to doping words are already present at the onset of adolescence, and that they may be linked to a psychological feature (physical self-esteem) considered as a risk factor of substance abuse in young adults involved in competitive sports.     

Commuting Conversions vs. the Standard Conversions of the “Good” Connectives

Commuting conversions were introduced in the natural deduction calculus as ad hoc devices for the purpose of guaranteeing the subformula property in normal proofs. In a well known book, Jean-Yves Girard commented harshly on these conversions, saying that ‘one tends to think that natural deduction should be modified to correct such atrocities.’ We present an embedding of the intuitionistic predicate calculus into a second-order predicative system for which there is no need for commuting conversions. Furthermore, we show that the redex and the conversum of a commuting conversion of the original calculus translate into equivalent derivations by means of a series of bidirectional applications of standard conversions. Presented by Heinrich Wansing and Jacek Malinowski     

Charitable giving among the foreign-born in Canada

This article focuses on the patterns of charitable giving among the foreign-born in Canada. Using Joseph's (1995) “spectrum of philanthropy” model, we generated four general empirical predictions that were explored with Canadian data. The sample used for the analysis were 18,301 Canadian and foreign-born respondents drawn from the National Survey of Giving, Volunteering and Participating. All four predictions were supported by the survey data. Substantial variations in the propensities to give were found among immigrant groups in terms of their birthplaces, socio-demographic, and residential characteristics. Some segments of the immigrant population displayed higher propensities to give than those who were Canadian-born. As the length of residence increased, the average contributions of the foreign-born increased but with some changes in their underlying motivations and organizational preferences. Religion-related motivations declined some-what over time. Although religious organizations were always preferred throughout the immigrant integration process, it was found that more secular organizations (i.e., health-and social services-related) received more support at the latter stages of this process.