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Sökning: WFRF:(Granér Simon)

  • Resultat 1-9 av 9
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  • Dahl, Mats, et al. (författare)
  • Analysis of eyewitness testimony in a police shooting with fatal outcome–Manifestations of spatial and temporal distortions
  • Ingår i: Cogent Psychology. - : Cogent OA. - 2331-1908. ; 5:1, s. 1-10
  • Tidskriftsartikel (refereegranskat)abstract
    • Eyewitness statements are commonly used in the criminal justice system and viewed as having a high-probative value, especially when the witness has no motive to lie, other witness recollection corroborates the account, or the witness is highly confident. A fatal police shooting incident in Sweden had 13 witnesses (nine civilians and four police officers) and was also filmed with two mobile phones. All interviews were conducted before witnesses viewed the films, allowing for the analysis of discrepancies between their statements and the videos. In this incident, a police patrol was sent to find out a man who was reported to have attacked two persons with a knife. When found, the perpetrator refused to obey the officer’s commands, and the police eventually shot at him. The analysis showed clear differences between the witness testimonies and the film. Elements associated with perceived threat, for example, the assailant’s armament and movement direction and number of shots fired, were remembered fairly accurately. However, most witnesses poorly recollected when, that is, after which shot, the assailant fell to the ground. Moreover, memory of the actual order of events was altered and important aspects omitted that were crucial from a legal point of view.
  • Bertilsson, Johan, et al. (författare)
  • Stress Levels Escalate When Repeatedly Performing Tasks Involving Threats
  • 2019
  • Ingår i: Frontiers in Psychology. - : Frontiers. - 1664-1078. ; 10, s. 1562-1562
  • Tidskriftsartikel (refereegranskat)abstract
    • Police work may include performing repeated tasks under the influence of psychological stress, which can affect perceptual, cognitive and motor performance. However, it is largely unknown how repeatedly performing stressful tasks physically affect police officers in terms of heart rate and pupil diameter properties. Psychological stress is commonly assessed by monitoring the changes in these biomarkers. Heart rate and pupil diameter was measured in 12 male police officers when performing a sequence of four stressful tasks, each lasting between 20 and 130 s. The participants were first placed in a dimly illuminated anteroom before allowed to enter a brightly lit room where a scenario was played out. After each task was performed, the participants returned to the anteroom for about 30 s before performing the next sequential task. Performing a repeated sequence of stressful tasks caused a significant increase in heart rate (p = 0.005). The heart rate started to increase already before entering the scenario room and was significantly larger just after starting the task than just before starting the task (p < 0.001). This pattern was more marked during the first tasks (p < 0.001). Issuance of a verbal "abort" command which terminated the tasks led to a significant increase of heart rate (p = 0.002), especially when performing the first tasks (p = 0.002). The pupil diameter changed significantly during the repeated tasks during all phases but in a complex pattern where the pupil diameter reached a minimum during task 2 followed by an increase during tasks 3 and 4 (p ≤ 0.020). During the initial tasks, the pupil size (p = 0.014) increased significantly. The results suggest that being repeatedly exposed to stressful tasks can produce in itself an escalation of psychological stress, this even prior to being exposed to the task. However, the characteristics of both the heart rate and pupil diameter were complex, thus, the findings highlight the importance of studying the effects and dynamics of different stress-generating factors. Monitoring heart rate was found useful to screen for stress responses, and thus, to be a vehicle for indication if and when rotation of deployed personnel is necessary to avoid sustained high stress exposures.
  • Bertilsson, Johan, et al. (författare)
  • Towards systematic and objective evaluation of police officer performance in stressful situations
  • 2020
  • Ingår i: Police Practice and Research. - : Taylor & Francis. - 1561-4263.
  • Tidskriftsartikel (refereegranskat)abstract
    • To ensure a continuous high standard of police units, it is critical to recruit people who perform well in stressful situations. Today, this selection process includes performing a large series of tests, which still may not objectively reveal a person’s capacity to handle a life-threatening situation when subjected to high levels of stress. To obtain more systematic and objective data, 12 police officers were exposed to six scenarios with varying levels of threat while their heart rate and pupil size were monitored. The scenarios were filmed and six expert evaluators assessed the performance of the police officers according to seven predefined criteria. Four of the scenarios included addressing a moderate threat level task and the scenarios were executed in a rapid sequence. Two further scenarios included a familiar firearm drill performed during high and low threat situations. The results showed that there was a large agreement between the experts in how they judged the performance of the police officers (p < 0.001). Performance increased significantly over tasks in four of the seven evaluation criteria (p ≤ 0.037). There was also a significant effect of pupil size (p = 0.004), but not heart rate, when comparing the different sequential scenarios. Moreover, a high level of threat considerably impaired the motor performance of the police officers during the firearms drill (p = 0.002). Finally, the pupil seemed to systematically dilate more when a threat appeared immediately than with a delay in the scenarios (p = 0.007). We conclude that systematic and quantitative judgments from experts provide valuable and reliable information about the performance of participants in realistic and stressful policing scenarios. Furthermore, objective physiological measures of heart rate and pupil size may help to explain and understand why performance sometimes deteriorates.
  • Bunke, Sofia, et al. (författare)
  • Idrotts- och motionspsykologi
  • 2016
  • Ingår i: Idrottsvetenskap. - : Studentlitteratur AB. - 9789144074689 ; 1, s. 113-143
  • Bokkapitel (refereegranskat)
  • Granér, Simon (författare)
  • Collective Collapse and Performance Contagion in Basketball
  • 2010
  • Doktorsavhandling (övrigt vetenskapligt)abstract
    • In this thesis, collective collapse in basketball is investigated. Although experienced by most team sport players, the phenomenon still puzzles the world of sports. Collective collapse is described as a sudden decrease in performance quality by a sport team, often with a devastating effect on the game outcome. The condition implies a social process, i.e. there is an impact on a majority of the team’s players that in turn influences the performance of the individual player. The phenomenon has received little scientific attention, thus there are no “ready to use” theories at hand to explain it. In Study I, a qualitative method is used to describe athletes’ and coaches’ experiences of collective collapse in basketball. A simulated recall interview technique is used where data is analysed according to the interpretative phenomenological method, resulting in a hierarchical structure of clusters. The clusters illustrate a collective collapse as a certain pattern of behaviour on the level of team and individual (passivity, individualism), emotional experience during the collective collapse episode (frustration, irritation) and group dynamic factors (lack of leadership and communication). In Study II, an experimental situation is set up where the intention is to artificially evoke participants’ poor performance when competing in a basketball shooting task. This is done by confronting them with a (pre-instructed) underperforming teammate (“the confederate”) used for manipulation. However, when compared with the control condition, the participants are not found to have been influenced, but they believe they have been. In Study III, archival data from basketball performance statistics is used for an intraclass correlational design. The results indicate that performance contagion exists. The conclusions drawn from the three studies are that collective collapse can be explained as a process beginning with a performance anomaly, where some players perform below expected standards at the same time as a function of chance, but where the anomaly is perceived as having a psychological mechanism. Such poor performance might develop into a contagious condition, where individuals influence each other to perform worse and worse, resulting in a downward spiral. A collective collapse can be viewed as a group dynamic phenomenon where roles and functions within the social structure of the team are ruptured, which in turn weakens the performance of the individual, accentuating dysfunctional behaviour for both individual and team. One explanation does not exclude the other, since a combination of factors appear to operate simultaneously.
  • Moesch, Karin, et al. (författare)
  • Hard fact or illusion? An investigation on momentum in female elite handball from a team perspective
  • 2014
  • Ingår i: International Journal of Sport and Exercise Psychology. - : Fitness Information Technology Inc.. - 1557-251X. ; 12:2, s. 106-120
  • Tidskriftsartikel (refereegranskat)abstract
    • Athletes constantly report experiences of momentum during athletic contests, and they consider momentum as being an important factor for the outcome of a competition. However, researchers trying to capture momentum with quantitative methods see themselves confronted with inconclusive results. To explain this gap between athletes’ belief and results from quantitative data, it is hypothesised that momentum might not necessarily happen in every match, and/or that momentum only emerges in short periods of a match. Taking into account limitations of research done so far, the present study investigates the prevalence of momentum, defined from a behavioural perspective and measured through serial dependence and non-stationarity, in female elite handball. In order to take into account players’ judgements of different match events, a pre-study was done with 49 female elite players. These data were used to estimate autocorrelations and χ2 tests from 43 matches in 2 play-off round of the Swedish Championships. In line with existing studies, the results confirmed that momentum was difficult to capture in the behavioural analysis: The results revealed that only 11.6% (autocorrelations), respectively, 16.3% (χ2 tests) of the matches showed signs for momentum, and some matches even showed signs for anti-momentum. However, it emerged that five-minute periods of momentum happen in nearly 75% of all matches. This result led to the hypothesis that athletes base their belief in momentum on such short-term periods, but that momentum normally not lasts for a complete match. The results are discussed in light of the existing literature, and propositions for future research are provided.
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