Functions of the vibrissae in the defensive and aggressive behavior of the rat

Removal of mystacial vibrissae for strange rats placed in an established rat colony produced reliable decrements in defensive boxing for these animals, and corresponding increases in freezing. In a subsequent experiment, removal of the vibrissae of the attacking colony males did not change the attack behavior of the vibrissectomized animals. These results indicate that the vibrissae are involved in defensive boxing behavior, but play no essential role in the elicitation or maintenance of conspecific attack in the rat.     

Reflexive fighting in the albino rat: Aggressive or defensive behavior?

Specific agonistic responses of albino rats were compared for dominant colony rats and intruders, and for rats in a “reflexive fighting” task. The “reflexive fighters” showed high levels of defensive responses such as boxing and freezing, and very low levels of aggressive behaviors such as piloerection, biting, and the lateral display. This pattern clearly suggests that the behaviors measured in the reflexive fighting task reflect conspecific defensive reactions, rather than “shockelicited aggression.” Moreover, striking responses seen in the reflexive fighting task also occur at a high rate when footshock is given to a solitary rat held in a boxing posture. Thus it appears that “reflexive fighting” primarily involves defensive rather than aggressive responses.     

Aggressive behaviors of the japanese brown bear

Film analysis and direct observation suggest that 2 very different types of intra-specific fights occur among Japanese brown bears maintained in large stable colonies. Disputes arising over food are short, and involve such activities as threatening, muzzling, chasing, and flight. Weapon use during feeding fights primarily involves slashing blows to the back or head areas of the opponent. In contrast, “spontaneous” fights are longer, and consist almost exclusively of wrestling, with bites and forepaw blows directed at the opponent's ruff area. These spontaneous fights occur primarily among the larger and higher-ranked male bears, especially among animals with closely adjacent rankings. It is suggested that such fights facilitate the establishment of dominance relationships by providing an opportunity for mutual assessment of strength and stamina without serious risk of injury.     

Social dominance and individual aggressiveness

Male rats exhibiting high, moderate, or low levels of offensive aggressive behavior in interactions with intruders in their home cage were grouped in mixed-sex colonies with 1 male of each aggression-level group in each colony. Agonistic interactions measured 1, 2, 3, 7, 14, 21, and 22 days after colony formation indicated that highly aggressive males on pretests continued to be more aggressive, becoming the dominant colony male in five of seven colonies and attacking intruders more often than less aggressive males. In the two remaining colonies the moderately aggressive male became dominant. This relationship, which was consistent over a number of indices, including offensive and defensive behaviors, and wound counts and wound sites, was seen even when a substantial weight differential favored the less aggressive animal. Dominance relationships were rapidly established and within-group fighting declined significantly over the 21-day test period. Pretest offensive levels also influenced the behavior of subordinates, with high or moderately aggressive subordinates showing more defense in interactions with dominants and receiving more wounds than did low-aggression subordinates. Dominant males also showed more defense in interacting with those subordinates which had been more aggressive during pretests. This pattern of results suggests that aggression level of the subordinate as well as the dominant may be an important factor determining the intensity of agonistic interactions in male rats.     

Developing a sense of virtual community measure.

Sense of virtual community is an important feature of virtual communities. This study develops a sense of virtual community (SOVC) measure, building off the strengths of a widely used measure of sense of community (SOC) for face-to-face communities. Although there is overlap between the senses of community for face-to-face and virtual communities, there are significant differences. The new SOVC measure is compared to the SOC measure on 265 members of seven online groups, explaining at least 7% more of the variance from exchanging support and member identification. This study represents an important step in developing a valid measure of SOCV.     

On the Assessment of Situational Intrinsic and Extrinsic Motivation: The Situational Motivation Scale (SIMS)

The purpose of the present research was to develop and validate a situational (or state) measure of motivation, the Situational Motivation Scale (SIMS). The SIMS is designed to assess the constructs of intrinsic motivation, identified regulation, external regulation, and amotivation (E. L. Deci & R. M. Ryan, 1985, 1991) in field and laboratory settings. Five studies were conducted to develop and validate the SIMS. Overall, results show that the SIMS is composed of 4 internally consistent factors. The construct validity of the scale is also supported by correlations with other constructs as postulated by current theories. Moreover, the SIMS is responsive to experimental induction as evidenced by data gathered through a laboratory study. In sum, the SIMS represents a brief and versatile self-report measure of situational intrinsic motivation, identified regulation, external regulation, and amotivation.     

Antipredator behavior of Swiss-Webster mice in a visible burrow system

Swiss-Webster mice living in a visible burrow system (VBS) reacted to presentation of a live cat in the surface area of the VBS by retreat to the burrows and reductions in nondefensive behaviors such as eating and drinking. Live eat-exposed subjects remained in the burrows 14 hr or more, while subjects exposed to a toy (plush) cat prior to live cat exposure reemerged almost immediately and made many contacts with the toy cat. However, subjects exposed first to the cat and later to a toy cat showed intermediate surface reemergence times and cat contacts during toy cat tests, indicating strong sensitization effects of prior live cat exposure. Previous studies indicated that rats in this situation show retreat to the burrows, surface avoidance, and reduction in nondefensive behaviors. The mouse pattern was similar, with the notable exception that in the first 5min block after cat presentation, mice rapidly alternated retreat to the burrow chambers with reappearance in the tunnel segment near the surface, to scan the surface visually and sniff. Movement during this time block involved a stretch attend posture characteristic also of risk assessment activities in rats. Such visual and olfactory inspection of the cat is not seen in rats in the VBS. This difference may be related to the finding that rats, but not mice, emit ultrasonic “alarm cries” during and after cat exposure. © 1995 Wiley-Liss, Inc.     

What Do Confidence Items Measure in the Physical Activity Domain?1

The study's purpose was to examine the measurement domain of confidence items used in physical activity research. We hypothesized that confidence items, including a phrase to hold motivation constant, would differ from standard confidence items. Participants (N = 248 students) completed confidence items, a thought‐listing procedure, and a 2‐week self‐report of physical activity. Results showed that confidence items with motivation held constant loaded exclusively on one factor, but standard confidence items were factor complex with intention. Correlations with physical activity intention and behavior were larger for confidence items than confidence items with motivation held constant. Finally, the thought‐listing procedure identified that 3 of the 7 reasons for answering confidence items were outside the intended measurement domain of self‐efficacy.