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.     

Generalization of equivalence relations from photos to objects by preschool children

Generalized equivalence classes are stimulus classes that consist of equivalent stimuli and other physically similar class‐member stimuli. The present study evaluated whether preschool children would form equivalence classes among photos of abstract objects (2D) and show equivalence generalization to the corresponding objects (3D), printed photos (2D stimuli), and to black‐and‐white drawn pictures (2D stimuli). Six typically developing children were taught arbitrary relations to establish three 3‐member equivalence classes with 2D stimuli presented on a computer screen. AB‐AC baseline relations (for half of the participants) and AB‐BC relations (for the other half) were taught using a multiple‐probe design to assess taught and tested relations. After class formation, three types of generalization probes were conducted: generalization to 3D stimuli, generalization between 2D (printed photos) and 3D stimuli, and generalization to drawn pictures (2D). All of the participants formed the equivalence classes. Two participants met the criterion for all three generalization probe types. Two participants presented mixed results across tests, and two participants did not exhibit equivalence generalization. The results demonstrated equivalence generalization from 2D to 3D stimuli in preschool children, although the variability across participants suggests that such generalization cannot be assumed a priori.     

Negative affect as a predisposing factor for cortisol release after an acute stress--the impact of unpleasant priming

Glucocorticoids have a key role in stress responses. There are, however, substantial differences in cortisol reactivity among individuals. We investigated if affective trait and mood induction influence the reactivity to psychological stress in a group of 63 young adults, male (n=27) and female (n=36), aged ca. 21 years. On the experimental day the participants viewed either a block of pleasant or unpleasant pictures for 5 min to induce positive or negative mood, respectively. Then, they had 5 min to prepare a speech to be delivered in front of a video-camera. Saliva samples were collected to measure cortisol, and questionnaire-based affective scales were used to estimate emotional states and traits. Compared to basal levels, a cortisol response to the acute speech stressor was only seen for those who had first viewed unpleasant pictures and scored above the average on the negative affect scale. There were no sex differences. In conclusion, high negative affect associated with exposure to an unpleasant context increased sensitivity to an acute stressor, and was critical to stimulation of cortisol release by the speech stressor.     

The amygdala is involved in the modulation of long-term memory, but not in working or short-term memory

Rats with cannulae implanted in the junction between the central and the basolateral nuclei of the amygdala were trained in one-trial step-down inhibitory avoidance and tested at 3 s for working memory (WM) or 1.5 or 24 h later for short-term memory (STM) and long-term memory (LTM), respectively. Several drugs were infused 6 min prior to training in the animals in which WM was measured or 0 min posttraining in those in which STM and LTM were measured: the glutamate receptor antagonists CNQX (0.5 microg) and AP5 (5.0 microg), the indirect GABA A receptor antagonist picrotoxin (0.08 microg), the cholinergic muscarinic receptor blocker scopolamine (2. 0 microg), norepinephrine (0.3 microg), the protein kinase C inhibitor staurosporin (1.0 microg), or the calcium/calmodulin dependent protein kinase II inhibitor Kn-62 (3.5 ng). None of the drugs had any effect on either WM or STM. All had, as previously shown, strong effects on LTM: picrotoxin and norepinephrine enhanced it, and CNQX, AP5, scopolamine, Kn-62, and staurosporin inhibited it. The results do not support the idea that memory of this task is formed in the amygdala; they indicate that the amygdala is not involved in WM or STM processing and support the idea that the amygdala modulates LTM storage processes carried out elsewhere.     

Multideductive Logic And The Theoretic-Formal Unification Of Physical Theories

We present a kind of logic named multideductive logic and outline an application of it in the problem of theoretic-formal unification of physical theories dealing with the Bohr atom theory. This is just a preliminary study that will be developed in future papers.     

Dolls are for Girls and Not for Boys: Evaluating the Appropriateness of the Implicit Relational Assessment Procedure for School-Age Children

The Psychological Record - The Implicit Relational Assessment Procedure (IRAP) has been used for assessing implicit attitudes across different domains. The current study aimed to investigate...     

Effects of posttraining treatments in the posterior cingulate cortex on short- and long-term memory for inhibitory avoidance in rats

Adult male Wistar rats were bilaterally implanted with indwelling cannulae in the caudal region of the posterior cingulate cortex. After recovery, animals were trained in a step-down inhibitory avoidance task (3.0-s, 0.4-mA foot shock) and received, right after training, a 0.5-microl infusion of vehicle (phosphate-buffered saline, pH 7.4), of the GABA(A) receptor agonist muscimol (0.1 or 0.5 microg), of the cAMP-dependent protein kinase (PKA) stimulant Sp-cAMPS (0.1 or 0.5 microg), or of the PKA inhibitor Rp-cAMPS (0.1 or 0.5 microg). Animals were tested twice, 1.5 h and, again, 24 h after training, in order to examine the effects of these agents on short- and long-term memory, respectively. Muscimol (0.5 but not 0.1 microg) hindered retention for both short- and long-term memory (p <.05). Rp-cAMPS (0.1 or 0.5 microg) hindered retention for short-term memory (p <.05). In addition, these animals showed lower, but not significantly lower, latencies than controls in the test session for long-term memory (p >.10). A trend toward an amnesic effect on long-term memory was also observed after Sp-cAMPS infusion at 0.1 microg (p <.10). These results show that strong stimulation of GABAergic synapses in the caudal region of the rat posterior cingulate cortex right after training impairs short- and long-term memory (the latter less dramatically). The same occurs by inhibiting PKA activity with regard to STM and possibly to LTM.     

Parental Practices and Theory of Mind Development

In the past three decades, psychologists have become increasingly interested in the study of theory of mind. This ability involves an understanding of different components of the mind (e.g., emotions, thoughts, beliefs) and of how they are related to human behavior. Several parents’ characteristics (e.g., attachment, mental-state talk) have been associated to children’s theory-of-mind development, but the variables and methods adopted are diverse and at times lead to inconsistent findings. The goal of the present paper, therefore, is to provide a literature review that can point both to possible ways in which discrepancies might be overcome and to promising research directions. Our review covers 78 research reports published in English between 1980 and 2011. Only empirical studies, using children as participants, were included in the review. Three main suggestions are offered for researchers, parents and practitioners on how to nurture young children’s understanding of mind: (a) to treat children as intentional agents, acting in a sensitive and responsive fashion to their mental states; (b) to speak to children about mental states in an elaborate and connected way, pointing out their causes and consequences, and explaining that these may be different for different people; and (c) to expose children to a wide range of emotions while being careful to not express over-frequent and inconsistent negative affect. One limitation of the present review, however, is that we do not look into how parental practices interact with certain individual characteristics of the child (e.g., personality, IQ and language skills). Future research should explore the multifaceted nature of these relationships and interactions.