Compression as a Universal Principle of Animal Behavior

A key aim in biology and psychology is to identify fundamental principles underpinning the behavior of animals, including humans. Analyses of human language and the behavior of a range of non‐human animal species have provided evidence for a common pattern underlying diverse behavioral phenomena: Words follow Zipf's law of brevity (the tendency of more frequently used words to be shorter), and conformity to this general pattern has been seen in the behavior of a number of other animals. It has been argued that the presence of this law is a sign of efficient coding in the information theoretic sense. However, no strong direct connection has been demonstrated between the law and compression, the information theoretic principle of minimizing the expected length of a code. Here, we show that minimizing the expected code length implies that the length of a word cannot increase as its frequency increases. Furthermore, we show that the mean code length or duration is significantly small in human language, and also in the behavior of other species in all cases where agreement with the law of brevity has been found. We argue that compression is a general principle of animal behavior that reflects selection for efficiency of coding.     

Helping My Patients Find New Spontaneous Ways of Responding Emotionally: A 30-Year Long Journey as a Psychoanalyst

I started my journey as a psychoanalyst with the conviction that I had to provide my patients, through interpretation, with explicit information about their instinctual unconscious that they didn’t have access to. Now I think that through words (often using highly metaphorical, poetic language, with its tone and rhythm), patient and analyst coconstruct new forms of relating, that is to say, new forms of mutual regulation of emotions. The aim of therapeutic change is that patients find new, spontaneous forms of reacting emotionally. This change, from the psychoanalysis of suspicion to the psychoanalysis of the secure base from where new regulating strategies are co-constructed, is parallel to the change in values observed at a social level: central values of industrialized society, such as obedience, authority, discipline, etc., are being replaced by values such as authenticity and respect for one’s uniqueness in electronic societies.     

Longitudinal Associations Between Delinquent Behaviour of Friends and Delinquent Behaviour of Adolescents: Moderation by Adolescent Personality Traits

In this longitudinal study, we examined whether personality traits (parent‐rated Big Five personality traits) render some adolescents more susceptible than others to delinquent behaviour of friends, predicting rank‐order changes in adolescents' self‐reported delinquent behaviour. We examine susceptibility to both perceived (reported by adolescents) and self‐reported (reported by friends) delinquent behaviour of friends. Participants in this two‐wave study were 285 Dutch adolescents and their best friends. The adolescents (50% girls) were 15.5 years old on average (SD = 0.8 years), and their best friends (N = 176; 58% girls) were 15.1 years old (SD = 1.5 years). Perceived (but not self‐reported) delinquency of friends predicted a stronger increase in adolescent delinquency 1 year later, especially among adolescents low or average on conscientiousness. Emotional stability, agreeableness, extraversion and openness did not moderate associations between delinquency of friends and delinquency of adolescents. Our findings show that low conscientiousness serves as a risk factor, increasing vulnerability to perceived delinquent behaviour of friends, while high conscientiousness serves as a protective factor, increasing resilience to perceived delinquent behaviour of friends. Our findings also show that adolescents are susceptible to, and differ in susceptibility to, friends' delinquent behaviour as they perceive it—not to delinquent behaviour as reported by friends themselves. Copyright © 2015 European Association of Personality Psychology     

The effects of item material on encoding strategies: Survival processing compared to the method of loci

When imagining being stranded in the grasslands of a foreign land without any basic survival material, participants have a magnificent memory for words rated according to their usefulness in this particular situation. Numerous studies could demonstrate that survival processing boosts memory performance more than other memory enhancing techniques. The method of loci is an old mnemonic strategy used to enhance serial recall. This method encompasses navigating mentally through a familiar environment and placing the to-be-remembered items in specific locations. In the later recall phase, the participant re-imagines walking through the environment, “looking” for the to-be-remembered items. In two studies, we compared the survival scenario with the method of loci and two different control conditions. In addition, we manipulated the used word-material on two different dimensions (imageability and relevance) to analyse its influences on the two methods. For words high in imageability, we found that memory performance in the survival condition is comparable to the method of loci. However, for words low in imageability the method of loci proved to be more effective than survival processing. Furthermore, we found that survival relevance has a high impact on the amount of the survival processing effect, even when imageability is low.     

The neural cell adhesion molecule-derived peptide FGL facilitates long-term plasticity in the dentate gyrus in vivo

The neural cell adhesion molecule (NCAM) is known to play a role in developmental and structural processes but also in synaptic plasticity and memory of the adult animal. Recently, FGL, a NCAM mimetic peptide that binds to the Fibroblast Growth Factor Receptor 1 (FGFR-1), has been shown to have a beneficial impact on normal memory functioning, as well as to rescue some pathological cognitive impairments. Whether its facilitating impact may be mediated through promoting neuronal plasticity is not known. The present study was therefore designed to test whether FGL modulates the induction and maintenance of synaptic plasticity in the dentate gyrus (DG) in vivo. For this, we first assessed the effect of the FGL peptide on synaptic functions at perforant path-dentate gyrus synapses in the anesthetized rat. FGL, or its control inactive peptide, was injected locally 60 min before applying high-frequency stimulation (HFS) to the medial perforant path. The results suggest that although FGL did not alter basal synaptic transmission, it facilitated both the induction and maintenance of LTP. Interestingly, FGL also modified the heterosynaptic plasticity observed at the neighboring lateral perforant path synapses. The second series of experiments, using FGL intracerebroventricular infusion in the awake animal, confirmed its facilitating effect on LTP for up to 24 h. Our data also suggest that FGL could alter neurogenesis associated with LTP. In sum, these results show for the first time that enhancing NCAM functions by mimicking its heterophilic interaction with FGFR facilitates hippocampal synaptic plasticity in the awake, freely moving animal.     

Children and Politics: An Empirical Reassessment of Early Political Socialization

Demands for the inclusion of children, the youngest citizens, in democratic decision making are increasing. Although there is an abundance of empirical research on the political orientations of adolescents, there is a paucity of research on younger children's orientations. Our panel study of more than 700 children in their first year of primary school shows that these young children already exhibit consistent, structured political orientations. We examine the distribution and development of political knowledge, issue orientations, and notions of good citizenship. We find achievement differences between subgroups at the beginning of the school year, and these differences do not disappear. Children from ethnic minorities and lower socioeconomic residence areas show relatively less developed political orientations, and they do not improve as much over the school year as other children. Furthermore, normative political orientations and cognitive orientations differ in their development.     

Trait and state negative affect interactions moderate inhibitory control performance in emotionally loaded conditions

Following the framework that controlled performance is dependent upon cognitive and emotional processes which are inherently inter-linked, effects of trait and state negative affect (NA) on inhibitory control (IC) were studied in two experiments using an emotional day-night task (EDNT) - an inhibition based decision-making task embedded with emotional content. It was hypothesized that the effects of processing negatively loaded stimuli would depend on trait levels of negative and positive affects, particularly in conditions that entail IC. In Experiment 1, EDNT performance was compared with performance of an emotionally loaded control task that required to perform a dominant response rather than to inhibit it. In Experiment 2, EDNT performance was compared with an emotionally loaded control task that required performing an alternative rule which did not involve inhibiting the dominant response. Results of both Experiments showed that participants high on NA trait reactivity showed improved performance while processing ‘sad’ content, only in the inhibitory task and not in either of the control tasks. Results point to an interaction of trait and state factors in IC, and highlight the notion that heightened NA may sub-serve inhibition in sad contexts, which require counter-intuitive operations.     

Willem Blok's Contribution to Abstract Algebraic Logic

Willem Blok was one of the founders of the field Abstract Algebraic Logic. The paper describes his research in this field. Dedicated to the memory of Willem Johannes Blok     

The role of ethnic origin and situational information in teachers’ reactions to social exclusion among students

Social Psychology of Education - The current study investigated pre- and in-service teachers' reactions to interethnic exclusion in Germany. Using hypothetical scenarios, we examined a sample...