A new approach to the formation of equivalence classes in pigeons

Four pigeons were given simultaneous discrimination training with visual patterns arbitrarily divided into two sets, with the stimuli in one set designated A1, B1, C1, and D1 and those in the other set designated A2, B2, C2, and D2. In sequentially introduced training phases, the pigeons were exposed to a series of reversals to establish AB and then CD equivalences. In subsequent testing sessions, a subset of stimuli from one set served as positive stimuli and those from the other set as negative stimuli on training trials, and transfer of the reinforced relation to other members of the sets was tested with nonreinforced probe trials. The pigeons were trained further on AC and BD equivalences and then were tested for the emergence of untrained AD and BC equivalences. Two of the 4 pigeons exhibited the emergence of one of these untrained equivalences, evidence for the emergence of transitive relations. This finding suggests that the pigeons established three-member functional equivalence classes by incorporating separately trained multiple equivalence relations. Repeated reversal training and probe testing enabled us to explore the formation and expansion of functional equivalence classes in pigeons.     

Differential effects of reciprocity and attitude similarity across long- versus short-term mating contexts

Participants were 24 male and 32 female undergraduate and graduate students whom the authors recruited for an examination of the effects of attitude similarity and reciprocity on the degree of attraction toward potential mates. The authors examined the effects of these 2 variables on degree of liking in long-term and short-term contexts. The authors administered a vignette about a bogus stranger to each participant, varying the stranger's attitude similarity with and liking of the participant. The authors enclosed the vignette in a folder that described the stranger as having either very similar or very different attitudes from the participant and that included a passage that notified the participant that the stranger either likes or does not like him or her. The dependent variables included 4 indexes of the extent to which participants reported liking the bogus stranger: a scale that measured short-term mating items, a scale that measured long-term mating items, a degree-of-liking scale, and a behavioral-intention item. Across these 4 attraction-relevant dependent variables, the authors found significant main effects of the reciprocity variable. Also, the authors found a significant main effect of attitude similarity on the likability measure. The authors found significant main effects of reciprocity in a long-term mating context and a short-term mating context.     

Relationship between birth order and leadership style for nursery school children

36 nursery school children were given a revised form of Fiedler's (1967) least preferred co-worker scale designated as the least preferred playmate scale. The purpose was to investigate the relationship between least preferred playmate scores and the birth order of young children. A 2 X 2 contingency table was constructed between birth order (first and later born) and leadership style (high and low). The resulting chi squares were insignificant for the total population and for males. However, for females the results were significant with a higher percentage of firstborns being task-oriented (low score) and a higher percentage of later borns being relation-oriented (high score).     

Effectiveness of Web- and Mobile-Based Treatment of Subthreshold Depression With Adherence-Focused Guidance: A Single-Blind Randomized Controlled Trial

Evidence for the impact of psychological Interventions for subthreshold depression (sD) is conflicting. Moreover, human resources to deliver such treatments are limited. This study aimed to evaluate the effectiveness of a web-based intervention with adherence-focused guidance in the treatment of sD. Participants with sD (CES-D ≥ 16, no Major Depressive Disorder according to DSM-IV criteria, N = 204) recruited via a large health insurance were randomly allocated to a web-based mobile-supported cognitive-behavioral intervention or to a waitlist control condition with unrestricted access to usual care. The primary outcome was the reduction in depressive symptom severity as measured by blind diagnostic raters using the Quick Inventory of Depressive Symptomatology (QIDS) at posttreatment. There was a statistically significant between-group difference in QIDS scores at posttreatment in favor of the intervention group, F(1, 201) = 11.31, p = .001, corresponding to a medium effect size of d = 0.37 (95% CI 0.09–0.64) and a NNT of 7 (95%–CI 3.7–41.2). Significant effects in favour of the intervention group were also found for secondary outcomes such as quality of life, anxiety, and insomnia severity. Web-based self-help interventions with adherence-focused guidance could be an acceptable and effective approach to reduce a range of negative consequences associated with subclinical depression.     

Where is (im)balance? Necessity and construction of evaluated cut‐off points for effort‐reward imbalance and overcommitment

The use of cut‐off values is common in research on the effort‐reward imbalance (ERI) model. They are often used to identify health risk situations or behaviour at work, although little is known about their diagnostic properties. The aim of the study was to investigate empirically cut‐off points for the effort‐reward ratio and the overcommitment (OC) scale. The study was based on a sample of 302 teachers. According to the International Classification of Mental and Behavioural Disorders‐10 (ICD‐10), 115 subjects suffered from a mood disorder. The control group consisted of 187 matched healthy subjects. Receiver‐operating characteristic analyses were conducted using the ERI ratio and OC as diagnostic variables. A mood disorder served as gold standard reference test. Results demonstrated the ability of the effort‐reward ratio and OC to discriminate between diseased and healthy individuals. However, a comparison of the areas under the curve revealed a significantly higher diagnostic power for the effort‐reward ratio. According to the Youden index, optimal cut‐off points were ERI>0.715 and OC>16. Furthermore, sensitivity and specificity for different cut‐off values are presented. Results point to shortcomings in the ERI literature using established approaches to define cut‐off points. Validating cut‐off values is of particular importance in order to ensure valid results in ERI research.     

Human visual motion sensitivity: Evidence against a ratio theory of sensory coding

Luminance thresholds for downward moving contours were measured under several conditions of adaptation. Included was one condition which desensitized visual mechanisms responsive to downward motion. Another condition exerted equal effects on both up- and down-sensitive mechanisms. Thresholds for moving contours were unaffected by exposure to contours which moved in the opposite direction. This indicates that the perception of motion does not depend upon the relative activity in oppositely tuned, directionally selective visual mechanisms.     

Effects of paradigm and inter-stimulus interval on age differences in eyeblink classical conditioning in rabbits

The aim of this study was to examine parameters affecting age differences in eyeblink classical conditioning in a large sample of young and middle-aged rabbits. A total of 122 rabbits of mean ages of 4 or 26 mo were tested at inter-stimulus intervals (ISIs) of 600 or 750 msec in the delay or trace paradigms. Paradigm affected both age groups dramatically, with superior performance in the delay paradigm. ISI was salient as middle-aged rabbits were significantly impaired in 750-msec compared with 600-msec delays, and young rabbits were significantly less impaired in 600-msec than in 750-msec trace. Young rabbits performed equally well at both delay ISIs, and consequently, there were significant age differences in 750-msec but not in 600-msec delays. Middle-aged rabbits performed poorly at both 600- and 750-msec trace, resulting in significant age differences in 600-msec but not in 750-msec trace. Timing of the conditioned response has been associated with cerebellar cortical function. Normal aging of the cerebellar cortex likely contributed to the magnitude of the effect of ISI in delay conditioning in middle-aged rabbits. Results demonstrate that the magnitude of age differences in eyeblink conditioning can be enlarged or eliminated by ISI and paradigm.