Effects of post-trial administration of naloxone and beta-endorphin on shock-induced fighting in rats

To study the involvement of endogenous opioid peptides in the development of shock-induced fighting, naloxone (2 mg/kg) or beta-endorphin (10 micrograms/kg) was administered subcutaneously immediately after the session and during nine consecutive daily sessions to rats repeatedly exposed to electric shocks. beta-Endorphin blocked the development of shock-induced fighting while naloxone facilitated it but only when shock-induced fighting occurred at a low rate. The effects of beta-endorphin were time dependent since when beta-endorphin was injected 90 min after the shock session instead of immediately after, its impairing effect disappeared. In addition, naloxone blocked the impairment produced by beta-endorphin. Differential postsession treatment of each member of pairs of rats with naloxone and beta-endorphin resulted in a higher probability of rats treated with naloxone to be dominant over rats treated with beta-endorphin in the test situation. These results are discussed in relation with the possible involvement of endogenous opioids in the modulation of the physiological consequences of defensive behavioral responses to shock.     

A Multitrait-multimethod examination of Minnesota Multiphasic Personality Inventory (MMPI) and Millon Clinical Multiaxial Inventory (MCMI)

Recently, certain Minnesota Multiphasic Personality Inventory (MMPI) and Millon Clinical Multiaxial Inventory (MCMI) scales have seen increasing usage for the measurement of DSM-III personality disorders. The current study sought to identify the convergent and discriminant validity of these two sets of scales for this purpose. In general, the results indicated significant convergence across the two instruments. However, better convergent validity was found for scales representing those DSM-III disorders which are most consistent with the typology upon which the MCMI was based. In particular, convergent and discriminant validity results were poorest for Compulsive, Antisocial, and Passive-Aggressive personality scales.     

Effects of Communication Expectancies,Actual Communication,and Expectancy Disconfirmation on Evaluations of Communicators and Their Communication Behavior

The current investigation addressed (a) the perseverance of preinteraction expectancies in the face of actual communication behavior, (b) the separate effects of personal attribute and communication expectancies, and (c) the role of expectancy confirmation or disconfirmation on postinteraction evaluations. Participant perceivers were induced to hold positive or negative expectancies regarding a target partner's general personal attributes and specific communication behavior prior to a problem-solving discussion. They then interacted with a confederate target who communicated in a pleasant, involved fashion or its opposite, after which perceivers evaluated target personal attributes and communication behavior. All three hypotheses received at least partial support. Preinteractional expectancies, especially personal attribute ones, caused perceivers to evaluate targets and their communication behavior differently, with negatively valenced expectancies serving as negative violations. Relative to a pleasant, involved communication style, unpleasant, uninvolved communication was less expected and evaluated negatively, thus functioning as a negative violation; it also reduced credibility, attraction, and perceived rewardingness of the target. Finally, disconfirmatory communication altered target evaluations relative to confirmatory communication, especially for high-valence targets. These results lend support to the premises and predictions of expectancy violations theory.     

Two Contrasting Explanations of Involvement Violations:

Among the theories that address the impact of variations in immediacy behaviors during ongoing interactions are expectancy violations (EV) and discrepancy arousal (DA) theories. This study of the effects of violations of expectations on arousal, reciprocity, and compensation in the medical practitioner-patient relationship contrasts EV predictions with DA predictions. EV theory predicts that given a communicator with high reward valence, high and very high involvement (including touch and close proximity) should be met with reciprocation (increased involvement), and low and very low involvement should be met with compensation (increased involvement). DA theory predicts compensating very high involvement with decreased involvement, reciprocating high involvement with increased involvement, compensating low involvement with increased involvement, and reciprocating very low involvement, with decreased involvement. Results supported neither theory as all involvement changes were met with reciprocity. Additionally, although all violations/discrepancies were followed by changes in arousal, size of arousal change was not monotonically related to size of involvement change, as predicted by DA theory. Finally, although positive versus negative emotional experiences were not related to physiological indicators of arousal change, size of involvement change was directly related to the experience of positive and negative emotions. Thus, it appears that involvement change size directly predicts emotional experience and is not mediated by arousal change.     

The aggression test as a possible taxonomic tool in the Formica rufa group

The intra- and interspecific aggressive behavior of Formica polyctena, a species of the Formica rufa group, was analyzed and quantified both in the laboratory and in the field. This behavior was used as a potential taxonomic tool for gaining a better understanding of the phyletic relationships among the species within the group. No overt aggression was recorded toward members of the same species. To examine interspecific relationships, F. polyctena was first confronted with F. cunicularia, to ascertain its aggressiveness toward a distantly related species. All such encounters led immediately to overt and prolonged attacks with virtually no initial mutual inspection. This suggests that recognition of strangeness of the unrelated species is almost immediate in F. polyctena, as previously observed in F. lugubris and F. rufa toward the same antagonist. Subsequently, F. polyctena was contrasted with F. lugubris and F. rufa (also belonging to the F. rufa group) in order to compare these related species. Fierce attacks accompanied by all the elements of conflict behavior were observed in all encounters. Moreover, the degree of aggression in the field was higher than in laboratory-paired ants, possibly because of a territorial effect. These data and our previous and similar research indicate that the relationships between F. lugubris and F. rufa are closer than between these two species and F. polyctena. In considering different viewpoints on this problem, the validity of the aggression test is discussed and the opportunity to compare levels of aggressiveness among strictly sympatric samples of red wood ant species gathered from the same ecological environment are considered.     

Jung’s Axioms: An Introduction to Jung’s “Note on Number”

This article is an introduction to C. G. Jung’s handwritten note on natural numbers (in this issue), which became the basis of Marie-Louise von Franz’s book Number and Time. I present the historical background of Jung’s note and discuss part of its content using mostly Jung’s own words.     

Horses discriminate between human facial and vocal expressions of sadness and joy

Animal Cognition - Communication of emotions plays a key role in intraspecific social interactions and likely in interspecific interactions. Several studies have shown that animals perceive human...