Nureya Abarca

Percentage reward in an operant analogue to foraging

Abstract Pigeons ( Columba livia ) responding on an operant, conditioning analogue to foraging could either accept or reject a variable-interval 20-s schedule which always led to food or a variable-interval 5-s schedule which led to food on only a percentage of trials. The probability of accepting the certain alternative increased as the percentage of food trials for the uncertain alternative decreased. The probability of accepting the uncertain alternative increased with the percentage of food trials for this alternative. Subjects receiving all of their food in the experiment (‘closed economy’) and those requiring supplementation (‘open economy’) preferred whichever alternative provided the higher overall mean rate of reinforcement.

Sex differences in aversive and appetitive conditioning in two strains of rats

In order to examine sex differences in non sexual behavior, 40 rats of each sex from two strains (gray, A x C and albino, Sprague-Dawley) were trained, using different experimental procedures. In Experiment I, aversive conditioning in a one-way (easy task) and a two-way (difficult task) active avoidance task was examined. Results consistently showed that males of both strains were inferior to females in the acquisition of the two-way avoidance task. A significant interaction between sex of both strains and the difficulty of the task was found. In Experiment II, rats were trained in a Sutherland Apparatus in an easy (black vs. white) and a difficult (horizontal vs. vertical) visual discrimination task, using appetitive reinforcement; no differences between sexes were observed. A significant interaction, however, was found between strain and task, indicating a lower performance of the A x C strain in the difficult task. The results are discussed within the theoretical framework of the Yerkes-Dodson Law, which states a relationship between drive level, performance and different degrees of task difficulty.

Measurement Invariance of the Satisfaction With Life Scale Across 26 Countries

The Satisfaction With Life Scale (SWLS) is a commonly used life satisfaction scale. Cross-cultural researchers use SWLS to compare mean scores of life satisfaction across countries. Despite the wide use of SWLS in cross-cultural studies, measurement invariance of SWLS has rarely been investigated, and previous studies showed inconsistent findings. Therefore, we examined the measurement invariance of SWLS with samples collected from 26 countries. To test measurement invariance, we utilized three measurement invariance techniques: (a) multigroup confirmatory factor analysis (MG-CFA), (b) multilevel confirmatory factor analysis (ML-CFA), and (c) alignment optimization methods. The three methods demonstrated that configural and metric invariances of life satisfaction held across 26 countries, whereas scalar invariance did not. With partial invariance testing, we identified that the intercepts of Items 2, 4, and 5 were noninvariant. Based on two invariant intercepts, factor means of countries were compared. Chile showed the highest factor mean; Spain and Bulgaria showed the lowest. The findings enhance our understanding of life satisfaction across countries, and they provide researchers and practitioners with practical guidance on how to conduct measurement invariance testing across countries.