High risk factors of hostage barricade incidents in a Japanese sample

Hostage taking incidents in which the police besiege a particular location are known as hostage barricade incidents. The first aim of the present article was to examine the process of risk assessment in hostage incidents, using a group of police officers as the sample. The second aim was to identify the risk factors involved in hostage incidents and examine the degree of concordance between the risk as assessed by the police officers and the figures obtained from the analysis of actual hostage barricade incidents. For the purpose of this study, a survey was carried out across Japan, and 45 police officers responsible for hostage negotiation responded to the questionnaires. Additionally, a sample of 116 actual hostage barricade incidents that occurred in Japan from 1970 to 2002 was utilised to examine the high risk factors involved in such cases. As per the results, a majority of the police officers (73.3%), in response to an open‐ended question, indicated that the highly excited state of the hostage takers was dangerous for the hostages. Moreover, it was demonstrated in all 116 incidents that several factors such as ‘a long siege’ tended to increase the risk of deaths, though this was very rare (n = 4). On the other hand, the proportion of injuries to the hostages was high in expressive situations such as domestic situations or suicide attempt scenarios. On the whole, the results obtained from the analyses of actual incidents were consistent with those obtained from the police officers' risk assessment in many respects. However, the correlation between the degree of risk as assessed by the police officers and the actual rate of deaths/injuries to the hostages was very low. Copyright © 2004 John Wiley & Sons, Ltd.     

Do squirrel monkeys (<Emphasis Type="Italic">Saimiri sciureus</Emphasis>) and capuchin monkeys (<Emphasis Type="Italic">Cebus apella</Emphasis>) predict that looking leads to touching?

Squirrel monkeys (Saimiri sciureus) and capuchin monkeys (Cebus apella) were tested using an expectancy violation procedure to assess whether they use an actors gaze direction, signaled by congruent head and eye orientation, to predict subsequent behavior. The monkeys visually habituated to a repeated sequence in which the actor (a familiar human or a puppet) looked at an object and then picked it up, but they did not react strongly when the actor looked at an object but then picked up another object. Capuchin monkeys responses in the puppet condition were slightly more suggestive of expectancy. There was no differential responding to congruent versus incongruent look–touch sequences when familiarization trials were omitted. The weak findings contrast with a strongly positive result previously reported for tamarin monkeys. Additional evidence is required before concluding that behavior prediction based on gaze cues typifies primates; other approaches for studying how they process attention cues are indicated.This revised version was published online in March 2004 with corrections to Fig. 2. The number 1 in the bottom left panel should be a cross and was, moreover, misaligned.     

Performance of pigeons (Columba livia) on maze problems presented on the LCD screen: in search for preplanning ability in an avian species

The authors examined how pigeons (Columba livia) perform on 2-dimensional maze tasks on the LCD monitor and whether the pigeons preplan the solution before starting to solve the maze. After training 4 pigeons to move a red square (the target) to a blue square (the goal) by pecking, the authors exposed them to a variety of detour tasks having lines as a barrier. A preview phase was introduced, during which the pigeons were not allowed to peck at the monitor. Results of a set of experiments suggest that our pigeons successfully learned to solve these tasks, that they came to take an efficient strategy as the barriers became complex, and that they possibly preplan its solution, at least on familiar, well-practiced tasks.     

Spatial distance and mental construal of social events

Construal-level theory proposes that increasing the reported spatial distance of events leads individuals to represent the events by their central, abstract, global features (high-level construal) rather than by their peripheral, concrete, local features (low-level construal). Results of two experiments indicated that participants preferred to identify actions as ends rather than as means to a greater extent when these actions occurred at a spatially distant, as opposed to near, location (Study 1), and that they used more abstract language to recall spatially distant events, compared with near events (Study 2). These findings suggest that spatially distant events are associated with high-level construals, and that spatial distance can be conceptualized as a dimension of psychological distance.     

Factors influencing the relation between extraversion and pleasant affect

Factors that influence the relation between extraversion and pleasant affect were examined in 6 studies. In Studies 1 through 5, the authors used structural equation modeling techniques to test whether different extraversion and pleasant affect scales and the use of multiple methods of assessment influenced the strength of the relation. In Study 6, the authors conducted a meta-analysis of previous literature to calculate an average effect size and to assess the influence of moderator variables. Results from both the structural equation models and the meta-analysis showed that with only a few exceptions, the use of different extraversion and affect scales resulted in moderate to strong correlations. The use of "on-line" methods of mood assessment (moment reports or daily-diary reports) resulted in lower and more homogeneous correlations than did the use of global, retrospective measures of mood.     

Can squirrel monkeys (Saimiri sciureus) learn self-control? A study using food array selection tests and reverse-reward contingency

Eight squirrel monkeys (Saimiri sciureus) were presented with 2 stimulus arrays, namely 1 and 4 pieces of food, but they received only the array other than the one they reached for. In this reverse-reward condition, all monkeys initially showed a strong preference for the larger array. One monkey learned to reach toward the smaller array when a large-or-none reward contingency was applied (i.e., no reward followed a reach toward the larger array, but this array was given for a reach toward the smaller array). When correction trials and time-out were added to the large-or-none procedure, all remaining monkeys except 1 learned this form of self-control. Performance was maintained when correction trials were discontinued, the original reverse-reward condition was rerun, and novel array-size pairs were presented. This study demonstrates one form of self-control in a New World primate and shows the reverse-reward procedure to be a potentially valuable method for assessing species and individual differences in self-control and numerosity-related abilities.     

Choice reaction time of elbow flexion and extension during passive elbow motions

The effect of passive elbow motions on electromyographic reaction times (EMG-RTs) of the biceps brachii for elbow flexion and the triceps for elbow extension was investigated in 8 normal subjects, using a choice-RT task, in which the subject was uncertain about the response direction to perform until the arrival of response signal after the passive motion started. Compared to the static condition, choice EMG-RTs shortened only when the direction of passive and response movements was the same. It seems that passive motions act as prior information on direction of movement in the choice-RT task.     

Pointing At Smaller Food Amounts In An Analogue Of Boysen And Berntson's (1995) Procedure

Boysen and Berntson (1995) showed that apes could not learn to point to a small amount of candy in order to get a larger amount when pointing to the larger amount was reinforced by receipt of the alternate, smaller amount. They explained this result as an unlearned predisposition to reach for higher value foods that overrides the effects of reinforcement. This report tests their thesis. In the first condition, 3 monkeys chose between one raisin held in one hand by the experimenter and four raisins held in the other hand. If a monkey pointed at four raisins, it received one. If it pointed at one, it received four. Over ten 20-trial sessions, no monkey learned to point at the one-raisin alternative, a result similar to that of Boysen and Berntson. In the second condition, pointing at one raisin still produced four; however, pointing at four raisins now produced no reinforcement. In five 20-trial sessions, all monkeys learned to point at one raisin in order to get four. This finding demonstrates that at least in monkeys there is no predisposition to reach for higher value foods that cannot be readily overridden by reinforcement contingencies, and casts doubt on Boysen and Berntson's claim to have demonstrated such a process in apes.     

Septal lesions and biting attacks in rats bidirectionally selected for emotionality

Twenty-nine colonies composed of one female and two male rats of high or low emotional strain were established. A dominant male of each colony was identified based on its attacks on an intruder rat. It was found that dominant males of the low emotional strain colonies were significantly more aggressive than those of the high emotional strain. Septal lesions or sham operations were given to dominant males of both strain colonies. Intruder tests were followed and several aggressive behaviors were measured by VTR observation. Biting attacks of the high emotional strain decreased for 10 days after septal latencies were shortened by septal lesions. Lesions X Strain interaction was significant. These results suggest that septal lesion effects on biting attacks are influenced by artificial genetic operations.     

Formation of the sameness-difference concept by Japanese monkeys from a small number of color stimuli

Japanese monkeys were trained to form the sameness-difference concept. In Experiment 1, four monkeys were trained with two colors to discriminate matching stimulus pairs from nonmatching pairs by reinforcing only lever-pressing responses to matching pairs with a variable-interval schedule. Three monkeys showed successful transfer of this discrimination to two new colors, thus demonstrating that some Japanese monkeys are able to form this relational concept from a minimum number of stimuli. In Experiment 2, two monkeys were trained, in a Yes/No procedure with three colors, to press one lever under matching pairs and another lever under nonmatching pairs. Poor transfer performances to three new colors suggest that simultaneously establishing two different response patterns to matching and nonmatching pairs is ineffective in forming the concept. In Experiment 3, the amount of transfer to three new colors after mastering a standard three-color matching-to-sample task was compared with that of a modified task in which correct responses were reinforced with a within-trial variable-interval schedule. All three monkeys showed greater transfer with the modified procedure. The results suggest that the variable-interval schedule adopted within trials is effective in forming the sameness-difference concept.