Counterexample Search in Diagram-Based Geometric Reasoning

Topological relations such as inside, outside, or intersection are ubiquitous to our spatial thinking. Here, we examined how people reason deductively with topological relations between points, lines, and circles in geometric diagrams. We hypothesized in particular that a counterexample search generally underlies this type of reasoning. We first verified that educated adults without specific math training were able to produce correct diagrammatic representations contained in the premisses of an inference. Our first experiment then revealed that subjects who correctly judged an inference as invalid almost always produced a counterexample to support their answer. Noticeably, even if the counterexample always bore a certain level of similarity to the initial diagram, we observed that an object was more likely to be varied between the two drawings if it was present in the conclusion of the inference. Experiments 2 and 3 then directly probed counterexample search. While participants were asked to evaluate a conclusion on the basis of a given diagram and some premisses, we modulated the difficulty of reaching a counterexample from the diagram. Our results indicate that both decreasing the counterexample density and increasing the counterexample distance impaired reasoning performance. Taken together, our results suggest that a search procedure for counterexamples, which proceeds object-wise, could underlie diagram-based geometric reasoning. Transposing points, lines, and circles to our spatial environment, the present study may ultimately provide insights on how humans reason about topological relations between positions, paths, and regions.     

Pigeons are attracted to a perceived gain without an actual gain

Reference dependence refers to the reduced value of a reward that is less than expected, or the added value of a reward that is greater than expected. There is evidence that when pigeons are offered an alternative that has 1 pellet versus an alternative that has 2 pellets, but one of the two pellets offered will be removed, the pigeons prefer the originally presented 1 pellet (loss aversion). In the present research, we tested for the opposite effect (gain attraction). In Experiments 1 and 2, pigeons could choose between 2 pellets, each one on a distinctive background. If they chose the optimal alternative, they received a second pellet. In Experiment 2, the second pellet obtained was the one not initially chosen (a task sometimes referred to as the ephemeral reward task). Pigeons learned to choose optimally in both experiments. In Experiment 3, we tested the pigeons for reference dependence. Pigeons were given an alternative that offered them one pellet or two pellets, if they chose the one-pellet alternative, they received an additional pellet, and if they chose the two-pellet alternative, they received the two pellets. In keeping with the reference dependence hypothesis, the pigeons preferred the 1-pellet alternative that gave them an extra pellet. These effects are related to similar findings with humans, including the endowment effect.

     

Personality pathology severity,cluster type and specific therapeutic interventions in outpatient psychotherapy

We explored the relationship between severity of personality pathology, cluster type and therapeutic interventions (psychodynamic–interpersonal [PI] and cognitive–behavioural [CB]) in 76 outpatients across two early sessions (3rd and 9th) of psychodynamic psychotherapy, while accounting for patients' baseline global symptom severity. Pretreatment personality pathology severity was assessed using the Personality Disorder Index (PDI), where DSM‐IV Axis II PD was assigned a value of 2, subclinical traits and features were assigned a 1 and absence of Axis II psychopathology was assigned a 0. Interrater reliability of personality pathology severity was excellent (ICC [1, 1]: 0.85). Interrater agreement for Cluster A (κ = 0.75), Cluster B (κ = 0.92) and Cluster C (κ = 0.70) was high. Interventions were coded with Comparative Psychotherapy Process Scale (CPPS) from videotapes, and reliability was excellent (CPPS‐PI = 0.86; CPPS‐CB = 0.78). Stepwise linear regressions indicated that therapists' focus on mood shift/topic avoidance (B = 0.29, p = .009) and future events (B = ?0.26, p = .020) predicted Axis II severity. Overall use of PI techniques and Cluster A personality disorder (CLA) were positively correlated (r = .312, p = .006). Stepwise binomial logistic regressions indicated that therapists' focus on uncomfortable feelings (B = 1.915, p = .008) and explaining rationale behind approach (B = 1.276, p =. 038) predicted CLA. All results remained significant when controlling for patients' baseline general symptomatology (Brief Symptom Inventory‐Global Severity Index [BSI‐GSI]), except for the relation between explaining rationale and CLA. Discussion highlights how using psychodynamic treatment model, therapists' focus on patient's in‐session affect expression and explaining rationale behind approach are highly relevant when working with CLA patients.     

Children's reasoning about responses to peer aggression: Victim's and witness's expected and prescribed behaviors

This research examined children's reasoning about expected (i.e., what a peer would do) and prescribed (i.e., what a peer should do) responses to unprovoked, intentional aggressive actions in two contexts: as a victim of such a transgression and as a witness to the incident. Physical harm and property damage items were used in a structured interview format. There were 90 subjects drawn from three elementary school grades (2nd, 4th, and 6th). Children differentiated between the expected and prescribed responses of peers and significant developmental differences in children's evaluations were found. Although the majority of the subjects in all grades denounced retaliation on the basis of concerns about others' welfare, older children stated that peers were likely to retaliate against the perpetrator nonetheless. Across different contexts, older children's responses appeared to reveal a greater independence from authority in negotiating peer interactions. In evaluating the witness's responses to aggressive acts, younger children's expected and prescribed responses were less disparate than that of the older children. The utility of including different vantage points of the child in examining children's social reasoning about aggression and the application of the present findings to social information-processing models are discussed. © 1996 Wiley-Liss, Inc.     

Effects of neonatal treatment with 1-(2,5-dimethoxy-4-lodophenyl)-2 aminopropane HCI (DOI) and ritanserin on agonistic behavior in adult male and female rats

The role played by the neonatal 5-hydroxytryptamine (5HT) system in the organization and sexual differentiation of adult agonistic behavior was investigated in rats. Focus was on the 5HT2 receptor subtype, which has been demonstrated to be involved in agonism control in the adult. 5HT2 activity was experimentally manipulated by administration of a specific agonist [1-(2, 5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (DOI)] or antagonist (ritanserin) during the second week of life, when serotonin is known to concur to anatomical and behavioral sexual differentiation. Interactions between early 5HT2 activity, genetic sex, and neonatal circulating testosterone (T) were studied by administering the ligands to males, females, and androgenized females. At adulthood, the animals were tested for both aspects of agonism, i. e., aggression and defense, in a 20-min confrontation with an unfamiliar conspecific of the same sex, age, body weight, and social experience. Neonatal administration of the 5HT2 antagonist ritanserin increased aggression independently of sex; it also increased defense, but this effect was confined to males. The agonist DOI had no effect on aggression, but enhanced defense in males and androgenized females, with an effect which depended therefore more on neonatal T than genetic sex. Females appeared in general less sensitive to neonatal 5HT2 manipulation than both androgenized females and males; this suggests that neonatal T is crucial for experimental modifications of neonatal 5HT2 activity to have any consistent effect on adult agonistic behavior. On the other hand, effects observed in males and androgenized females were dependent on the behavior considered and the drug administered. This was especially evident for defense, enhanced by ritanserin in males only, and in both males and androgenized females by DOI. Neonatal 5HT2 activity seems therefore to play a role in the modulation of adult agonistic behaviors, which depends on the behavior considered and is under multiple control of genetic sex and hormonal neonatal substrate. © 1994 Wiley-Liss, Inc.