The effect of asymmetrical sample training on retention functions for hedonic samples in rats

Rats were trained in a symbolic delayed matching-to-sample task to discriminate sample stimuli that consisted of the presence of food or the absence of food. Asymmetrical sample training was provided in which one group was initially trained with only the food sample and the other group was initially trained with only the no-food sample. In addition, within each group half of the rats were trained with an illuminated intertrial interval (ITI) and the remaining rats with a dark ITI. While the retention functions did not differ as a function of which sample was trained first, they did differ as a function of the similarity in the illumination conditions during the ITI and the delay interval. Symmetrical retention functions were obtained when the lighting conditions were similar and slightly asymmetrical retention functions were obtained when the lighting conditions were dissimilar. Probe tests confirmed that features of the no-food sample were attended to and used to generate a memory representation for the no-food sample. The results are not consistent with the hypothesis that asymmetrical sample training encourages coding of the sample introduced initially and default responding to the subsequently introduced sample. Rats generate memory representations for both samples when asymmetrical sample training is given with hedonic samples.     

Self‐regulation predicts risk‐taking through people's time horizon

In the context of decision‐making research, people's regulatory orientation mode (i.e., assessment and locomotion modes) has been included among the most prominent individual difference variables, which may potentially account for choice behaviour. Thus, the main objective of our experiment was to investigate the relations between habitual use of regulatory mode and risk‐taking through people's time horizon. Risk‐taking was appraised using a behavioural measure (i.e., BART) 1 month following evaluation of habitual use of regulatory mode. The findings revealed a significant negative association between the assessment mode and risk‐taking through individual differences in time horizon.     

Conditional Random Quantities and Compounds of Conditionals

In this paper we consider conditional random quantities (c.r.q.’s) in the setting of coherence. Based on betting scheme, a c.r.q. X|H is not looked at as a restriction but, in a more extended way, as \({XH + \mathbb{P}(X|H)H^c}\) ; in particular (the indicator of) a conditional event E|H is looked at as EH +  P(E|H)H ^c . This extended notion of c.r.q. allows algebraic developments among c.r.q.’s even if the conditioning events are different; then, for instance, we can give a meaning to the sum X|H + Y|K and we can define the iterated c.r.q. (X|H)|K. We analyze the conjunction of two conditional events, introduced by the authors in a recent work, in the setting of coherence. We show that the conjoined conditional is a conditional random quantity, which may be a conditional event when there are logical dependencies. Moreover, we introduce the negation of the conjunction and by applying De Morgan’s Law we obtain the disjoined conditional. Finally, we give the lower and upper bounds for the conjunction and disjunction of two conditional events, by showing that the usual probabilistic properties continue to hold.     

Numerical acuity of fish is improved in the presence of moving targets,but only in the subitizing range

There is controversy in comparative psychology about whether on the one hand non-symbolic number estimation of small (≤4) and large numbers involves a single mechanism (an approximate number system), or whether on the other hand enumeration of the numbers 1–4 is accomplished by a separate mechanism, an object tracking system. To date, support for the latter hypothesis has come only from the different ratio-dependency of performance seen in the two numerical ranges, a reading that has been criticized on several grounds. In humans, the two-system hypothesis is supported by evidence showing that manipulation of the physical properties of the stimuli (e.g., the motion of the items) has dissimilar effects on small- and large-number discrimination. In this research, we studied this effect on guppies. Initially, fish were trained to simultaneously discriminate two numerical contrasts having the same easy ratio (0.50): one in the small-number (2 vs. 4) range and one in the large-number (6 vs. 12) range. Half of the fish were presented with moving items; the other half were shown the same stimuli without motion. Fish were then subjected to non-reinforced probe trials in the presence of a more difficult ratio (0.75: 3 vs. 4 and 9 vs. 12). Under both static and moving conditions, the fish significantly discriminated 6 versus 12, but not 9 versus 12 items. As regards small numbers, both groups learned to discriminate a 0.50 ratio, but only fish tested with moving stimuli also discriminated 3 and 4 items. This differential effect suggests that fish may possess two separate systems for small- and large-number discrimination.     

Extensive training extends numerical abilities of guppies

Recent studies on animal mathematical abilities suggest that all vertebrates show comparable abilities when they are given spontaneous preference tests, such as selecting the larger number of food items, but that mammals and birds generally achieve much better performance than fish when tested with training procedures. At least part of these differences might be due to the fact that fish are usually trained with only one or two dozen trials while extensive training, sometimes with thousands of trials, is normally performed in studies of mammals and birds. To test this hypothesis, female guppies were trained on four consecutive numerical discriminations of increasing difficulty (from 2 vs. 3 to 5 vs. 6 items), with up to 120 trials with each discrimination. Five out of eight subjects discriminated all contrasts up to 4 versus 5 objects at levels significantly better than chance, a much higher limit than the 2 versus 3 limit previously reported in studies that provided fish with only short training sequences. Our findings indicate that the difference in numerical cognition between teleosts and warm-blooded vertebrates might be smaller than previously supposed.     

Systematic review of instruments measuring homophobia and related constructs

Since its conceptualization, the construct of homophobia has been the subject of many speculations about its specificity, reach, and possibility of empirical assessment. Several instruments have been created aiming to measure the prejudice against homosexuals. Peer‐reviewed articles of studies using measures to assess homophobia and related constructs were systematically reviewed in 4 databases (Medline, PsycINFO, ERIC, JSTOR). The articles were classified as they displayed evidence of the instrument's validity, reliability, or both. Finally, the instruments were rated according to that evidence. Out of 1076 results, 115 studies between 1993 and 2010 were identified as relevant. Those studies used 47 different instruments. This review focused in 5 instruments that concentrated the majority of the citations. Psychometric properties were acceptable.     

Associations of perceived stress and state anger with symptom burden and functional status in patients with heart failure

Abstract

Background: Psychosocial stress and anger trigger cardiovascular events, but their relationship to heart failure (HF) exacerbations is unclear. We investigated perceived stress and anger associations with HF functional status and symptoms.

Methods and Results: In a prospective cohort study (BETRHEART), 144 patients with HF (77% male; 57.5?±?11.5 years) were evaluated for perceived stress (Perceived Stress Scale; PSS) and state anger (STAXI) at baseline and every 2 weeks for 3 months. Objective functional status (6-min walk test; 6MWT) and health status (Kansas City Cardiomyopathy Questionnaire; KCCQ) were also measured biweekly. Linear mixed model analyses indicated that average PSS and greater than usual increases in PSS were associated with worsened KCCQ scores. Greater than usual increases in PSS were associated with worsened 6MWT. Average anger levels were associated with worsened KCCQ, and increases in anger were associated with worsened 6MWT. Adjusting for PSS, anger associations were no longer statistically significant. Adjusting for anger, PSS associations with KCCQ and 6MWT remained significant.

Conclusion: In patients with HF, both perceived stress and anger are associated with poorer functional and health status, but perceived stress is a stronger predictor. Negative effects of anger on HF functional status and health status may partly operate through psychological stress.