Preweanling and adult rats treat conditioned light-tone combinations differently

Ontogenetic differences in processing light-tone compounds were discovered in preweanling (17-day-old) and adult (60–80-day-old) rats. Suppression of general activity was used as an index of the magnitude of conditioned fear following a single training session in which a CS+ was paired with mild footshock. In Experiment 1, rats were trained on discriminations in which the CS? consisted of a light and the CS+ was either a tone alone (simple discrimination) or a light-tone compound (simultaneous feature-positive discrimination). Adults and preweanlings given each type of discrimination were then tested for fear of the CS? and a target stimulus (tone alone or light-tone compound). Adults in all groups displayed greater fear of the target than of the CS?. Preweanlings, however, discriminated the CS? from the target only when the target was the same as the original CS+. Experiment 2 revealed that age-related differences in conventional stimulus generalization is not a likely explanation for the pattern of results found in Experiment 1. Experiment 3 revealed age-related differences in expressed fear of a serial feature-positive discrimination; adults, but not preweanlings, showed greater fear of the compound than of the CS?. Alternative interpretations of the results from these experiments are discussed, and the general conclusion is that adults appear more inclined to process elements of a compound stimulus selectively, whereas preweanlings seem more likely to process the compound unselectively, with roughly equivalent processing of each element.     

Zum Problem der Hochschulreform in Spanien: Einige Ausgewählte Daten

Over the past ten years there has been a sweeping reform of the courses taught and qualifications awarded by Spanish universities. For that reason, an investigation was launched in 1996–97 at the University of Santiago de Compostela (in Northwest Spain) into the teaching, research and management entailed in four new degree courses: physics (years one to four), agricultural engineering (first and second years), agricultural food-processing technology (years one to three) and pharmacy. This article reports on students' opinions of the reforms in these courses, revealing dissatisfaction with facilities for practical course work, lack of connection with prospective employment, and a call for more information about courses.     

Differential Influence of Same- and Cross-Ethnic Friends on Ethnic-Racial Identity Development in Early Adolescence

Recent research has shown that peers influence ethnic-racial identity (ERI) development during early adolescence. Arguments based on social identity theory, however, suggest that only same-ethnic but not cross-ethnic friends are important for ERI development. Using longitudinal social network analysis, we examined peer influence of both same- and cross-ethnic friends on ERI attachment and private regard. Data were drawn from six ethnically diverse schools in Western Germany (N = 1,349; M_age = 13.3). Our results provide empirical evidence for early adolescents’ ERI being influenced by same- but less by cross-ethnic friends. Considering peers’ ethnicity therefore is crucial for understanding peer influence on ERI development.     

Uses of the Past in Refugee Documentaries in Sweden and Germany

Migration not only entangles people, cultures and societies but also histories and memories of diverse groups across national and cultural boundaries. The article focuses on mediated memory cultures of migration both theoretically and empirically. The first part discusses how cultural memories of migration in cross-medial flows of remediation can entangle ‘mnemonic imaginations’ of diverse groups within societies across time, cultures and media. In response to the conceptual framework of ‘entangled media histories’ this theoretical part explores entangled media histories of migration from the angle of memory studies. The second part of the article gives selected case studies. They reveal how media have historically mediated migratory memories and how they make use of this media history in contemporary productions. The examples are two Swedish documentary films of 2011 and 2015 and two German television documentaries of 2015 and 2016. With this theoretical and empirical approach the article shows how media actively contribute to debates about contemporary migration movements by the help of time-travelling migratory memory and media history.     

Devaluation of Pavlovian conditioning in the 10-day-old rat

This experiment established that for the infant rat, 10 days postpartum, a preference conditioned to an olfactory stimulus (conditioned stimulus) could be substantially-decreased-by subsequently lowering the value of the unconditioned stimulus (heat). This devaluation effect disappeared when a sufficiently long interval elapsed between the devaluation treatment and the test, despite maintained retention of the original conditioned preference over this same interval. This suggests that devaluation in infant rats does not permanently change the animal’s original representation of the unconditioned stimulus, but instead may replace it temporarily with a conflicting representation.     

Release from latent inhibition with delayed testing

A conditioned emotional response procedure was used to study the interactive effects of stimulus preexposure and retention interval in rats. In Experiment 1, the subjects were conditioned by presenting a light CS paired with mild footshock as the US. Half of the subjects were given nonreinforced preexposure to the CS, and the others were not. Separate preexposed and nonpreexposed groups were then tested 1,7, or 21 days after conditioning. Suppression of ongoing activity was used to assess the degree of conditioned fear. Latent inhibition was found at the 1-day retention interval; the preexposed subjects displayed less conditioned fear than did the nonpreexposed subjects. In contrast, equally strong conditioned fear was expressed by the preexposed and the nonpreexposed groups tested after the 7- and the 21-day retention intervals. These results indicate a release from latent inhibition similar to that obtained with conditioned taste aversions (Kraemer & Roberts, 1984). The results of Experiment 2 suggest that retention-interval-induced increases in sensitization, pseudoconditioning, or neophobia cannot account for the release from latent inhibition effect obtained in Experiment 1. The implications of these findings for a retrievaloriented view of latent inhibition are discussed.     

Absence of immediate transfer of training of duration symbolic-matching-to-sample in pigeons

Two experiments examined the performance of pigeons on symbolic-matching-to sample in which the relevant sample dimension consisted of duration. Each pigeon was trained on two problems that had the same two sample durations, 2 and 10 sec, but were different with respect to other physical properties of the samples. Durations of light and tone were used in Experiment 1; durations of two different color-location compounds were used in Experiment 2. In each experiment, a unique choice stimulus was associated with each of the four possible combinations of duration and signal type. Test sessions contained probe trials in which the choice stimuli were these appropriate for a long and a short duration of the signal type opposite to that actually presented. Pigeons in both experiments displayed asymmetrical performance deficits. Accuracy on long durations dropped to chance or below, whereas accuracy on short durations remained high. This pattern is similar to the choose-short effect that is obtained when animals are tested with long retention intervals. The implications of these results for duration memory, coding, and transfer of training are discussed.     

The influence of stimulus attributes on duration matching-to-sample in pigeons

A duration matching-to-sample procedure was used to examine the influence of signal properties on temporal estimation and working memory. The results indicated that pigeons responded to durations of a light as if they were longer than equal durations of the absence of the same light, but delay performances did not differ between the two sample types. Similarly, pigeons responded to durations of a bright white light as if they were longer than equal durations of a dim red light, but again, delay performances did not differ between the two sample types. These results are discussed in terms of theoretical issues pertinent to timing, attention, and working memory.