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Modeling the Effects of Stress: An Approach to Training

Taryn CuperMYMIC LLC

taryn. cuper@mymic.net

Abstract. Stress is an integral element of the operational conditions experienced by combat medics. Theeffects of stress can compromise the performance of combat medics who must reach and treat theircomrades under often threatening circumstances. Examples of these effects include tunnel vision, loss ofmotor control, and diminished hearing, which can result in an inability to perceive further danger, satisfactorilytreat the casualty, and communicate with others. While many training programs strive to recreate this stressto aid in the experiential learning process, stress inducement may not always be feasible or desired. Inaddition, live simulations are not always a practical, convenient, and repeatable method of training. Instead,presenting situational training on a personal computer is proposed as an effective training platform in whichthe effects of stress can be addressed in a different way. We explore the cognitive and motor effects ofstress, as well as the benefits of training for mitigating these effects in real life. While many trainingapplications focus on inducing stress in order to "condition" the stress response, the author explores thepossibilities of modeling stress to produce a similar effect. Can presenting modeled effects of stress helpprepare or inoculate soldiers for stressful situations in which they must perform at a high level? This paperinvestigates feasibility of modeling stress and describes the preliminary design considerations of a combatmedic training system that utilizes this method of battlefield preparation.

1.0 INTRODUCTION

Stress is defined as a condition typicallycharacterized by symptoms of mental and physicaltension and strain that can result from a reactionto a situation in which a person feels threatened,pressured, etc [1]. The effects of stress manifestboth emotionally and physiologically and can bebeneficial or detrimental to performance,depending on the level of stress and performancerequirements. In the case of a combat medic,stress levels can be expected to be extremely highas the lives of both the medic and his comradesare at risk. In addition, the medic's performancerequirements are complex, demanding both gross(e.g. running) and fine (e.g. applying a tourniquet,firing a weapon) motor skills as well as unaffectedcognitive functioning. Therefore, it is important totake into account the effects of stress whendesigning any combat medic training program inorder to adequately represent realistic situationsand to prepare medics with the tools andstrategies to effectively do their job.

This paper describes an investigation into theconcept of stress response modeling and itsinclusion in the design of a Complex IncidentResponse Training System (CIRTS) for CombatMedics (CM). The CIRTS-CM design is of a PCgame-based system for training combat medics torespond to lED-ambush scenes. While the primaryfoci of CIRTS-CM are site management and

casualty care, the integration of stress isconsidered an important element of providing arealistic approach to this type of training.

2.0 BACKGROUND

The emotional effects of stress include fear andanxiety while physiologically, stress results in, forexample, an increased heart rate. Stress alsoaffects cognitive functioning. When cognitive loadsurpasses capacity, the result can be decreasedperception of the environment and an inability tothink through known processes or to problem­solve [2]. Though the domains of the effects ofstress are often addressed separately, that is notto assume they are exclusive of one another.Instead, the effects of stress are interrelatedmechanisms that are divisible only by how theypresent in the face of a stress source, or stressor.

2.1 Physiological effects of stress

Siddle [3] refined reported effects of stress tophysiological measurements, linking thedeterioration of fine motor skills and cognitivefunctioning and the enhancement of gross motorskills to increasing heart rate:

• >115 bpm: loss of fine motor skills

• >145 bpm: loss of complex motor skills;visual system decreases the peripheralview and attention

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• >175 bpm: gross motor skills only;auditory exclusion; tunnel vision;"freezing"; deterioration of depthperception; deterioration of informationprocessing skills

This relationship between performance and heartrate can be explained by the Inverted UHypothesis, which states that performanceincreases with arousal (e.g. heart rate) up to acertain point, at which time performance starts todeteriorate. Levitt's research supports both thishypothesis and Siddle's findings, defining thispoint of descent at 145bpm, with optimalperformance between 115 and 145 bpm; heartrates below 80 and above 175 bpm correspond topoor performance [4].

These increases in arousal can affect almost allaspects of performance, especially vision, hearing,physical movement, and cognitive abilities, eithersingularly or in combination [5] depending on thelength and severity of an engagement [6].Following are some selected physiological effectsof combat-related stress from a collection of first­person reports compiled by Artwohl & Christensen[7]:

• Auditory exclusion: Inability to hear orseverely diminished hearing of one's ownand other's gunfire, as well as sirens andverbal communications; hearing a "pop"noise and/or the sound of the weapon'sslide moving forward and backwardinstead of the gunshot; sound of one'sown gunfire sound very far away. Inaddition, inability to hear the shot orexplosion that is close enough to harm.

• Tunnel vision or perceptual narrowing:seeing only the ring on a shooter's fingerwhile being fired at; focusing so intently onthe adversary's pistol, the office shot itand the trigger finger out of his hand;leveraging this phenomena on anadversary by side-stepping to gain theadvantage. In addition, the rareoccurrence of complete loss of sight, arare occurrence.

• "Scared speechless": inability to speakintelligibly into radio; making a "weird,inarticulate garbling sound" instead ofspeaking; focus on training police officersto give specified verbal instructions

constantly so that this is an automaticresponse in a real situation.

• Slow-motion time: time slowed so that anofficer felt he could consider options andcarefully aim in what was actually anextremely quick movement; ability to seebullets in the air as if they were low­velocity projectiles, e.g. paintball rounds.

A similar phenomena to these experiences ishypervigilance [8]. Hypervigilance is characterizedby freezing in place or existing in a state ofextreme agitation in reaction to perceived threat.In such cases, an individual may persist in afrantic search for escape routes, perform irrationalactions, or perform the same actions over andover again though they have proven ineffective atachieving the individual's goal. Each of thesereactions can be found within the effects of highperformance anxiety, which is characterized bythe, "temporary loss of cognitive efficiency and atemporary loss of perceptual acuity, perceptual­motor coordination, and motor skills," [9]. Thissimilarity in the effects of combat related stressand anxiety indicates that hypervigilance is acomplex response to both a perceived threat anda lack of confidence in one's ability to control thethreat.

2.2 Coping with and/or overcoming the effectsof stress

Training to expected conditions is a common wayto prepare individuals for the challenges they willface in a real-life situation. This can beaccomplished via live exercise with varying levelsof simulation augmentation [10] wherein traineeshave direct exposure to real-life or close to real-lifestressors. One of the goals of this approach is tomake training the first place these stressors areexperienced to hopefully mitigate their debilitatingeffects on an individual when his life is threatenedand/or his performance is a determining factor ofothers' survival.

Stress Inoculation Training (SIT) extends thisapproach, utilizing lessons learned from cognitivebehavioral therapy. This process consists of threephases: conceptualization, skills acquisition andrehearsal, and application and follow through [11].During the conceptualization phase, the trainee iseducated about the nature and possible impacts ofstress and trained to view stressors as problemsto be solved; in this way, the trainee's mentalmodel of the stress has been modified. Next is the

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skills acquisition and rehearsal phase, in whichcoping skills are taught and practiced in a"laboratory" setting. Last, during application andfollow-through, trainees apply the coping skills inincreasingly stressful situations, such as realistictraining scenarios. SIT has been successful atenhancing one's skill at coping in extremelystressful situations, such as military combat [12][13). A particularly significant aspect of SIT is theconceptualization phase, in which trainees areeducated about the effects of the stress they willencounter.

2.3 Survival stress management

Survival stress management can be bestcharacterized by first examining Martens'definition of stress [14], which emphasizes threatperception, perception of response capability, andperception of time required for effective threatmanagement. Survival stress managementtraining addresses these perceptions, the primarygoal of which is to increase the trainee'sconfidence in his own capabilities; remainingtraining goals include experience, visualization,and breathing [3].

As mentioned in the discussion above on therelationship between the effects of fear andanxiety, confidence is a determining factor of thestrength of one's survival stress response.Building this confidence takes a two-prongedapproach: confidence in the specific skills to beperformed and confidence in the context in whichthe skills are performed. As such, the traineebuilds this confidence through both skills trainingand effectiveness and experience throughdynamic exercises.

Recognition of the symptoms leading to adverseeffects of stress is a key component of learning tocontrol these effects. Situational awareness playsa role in this step as trainees learn to recognizepotential threats and visualize Plan A and Plan Bresponses. This objective is enhanced by the lasttraining goal of breath control. Among otherphysiological effects, controlling the rate ofbreathing can result in a lower heart rate, therebyminimizing the physiological effects of stressassociated with bpm above.

3.0 CIRTS-CM PRELIMINARY DESIGN FORSTRESS

Some training modalities are not amenable tostress inducement; in these cases, directexposure to stressors may not be practical,

feasible, or desired. For example, consider thetraining environment of the CIRTS-CM. In thiscase, it is not feasible to impart fear for one's lifeor the physical effects of running for cover to thetrainee when they are safely located in a trainingroom in front of a computer. While the trainee maybecome so engrossed in training that anaccompanying increase in heart rate isexperienced, this physiological response will notmeet the levels experienced in combat.

In addition, it is not desirable for this tool to inducestress for the purpose of eventual inoculation asthis additional training focus may take away fromthe stated training goals of the system. However,in recognition of a desire for elevated engagementand realism, the element of stress will beaddressed in a manner that can be adequatelyexecuted on a PC as well as enhance the traininggoals of the system.

Teaching the effects of stress, not only the effectson perception but also on the accompanyingeffects on job performance, is a uniqueopportunity for game-based training. Theproposed approach to this challenge is stressresponse modeling. This concept is similar to theconceptualization stage of SIT, in which traineesare educated about the effects of stress. It alsoaddresses the Visualization training goal ofsurvival stress management, in which traineeslearn to recognize the onset of survival stress inorder to take steps towards mitigation. In thisenvironment, stress response modeling can occurin situ; the nature of the model presents the effectof stress while the resulting inability of the traineeto perform actions that require that perceptivecapability compromises performance in the game,as it would in real life. This representation therebyenhances the realism of training modality.

For example, the CIRTS-CM will impose the effectof tunnel vision on the player by blacking out theperiphery of the screen. Another possibility ismuting the sound temporarily to replicate auditoryexclusion. These models can serve as practicalexperience to reinforce the education of the medicas to what can happen to him in a real-life, stressinducing scenario.

In addition to modeling the effects of stress to thetrainee, CIRTS-COM will address the element ofstress with regard to task difficulty. Externalstimuli, Le. visual and auditory stimuli, will buildfrom level to level, requiring high performance inthe face of diminishing cognitive resources.

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4.0 DISCUSSION

While examples of human stress responsemodeling are not common, two similar approacheswere identified and are explained below.

One example leverages technology to educatepeople on the effects of cognitive states other thanstress. In the domain of abnormal psychology, theUniversity of California at Davis has created theVirtual Hallucinations Project, which seeks toeducate by modeling an exemplar experience ofschizophrenia for visitors in the Second Life virtualworld [15]. Virtual Hallucinations presents visitorswith auditory and visual "hallucinations" similar towhat a schizophrenic might experience. This useof computer-based stimuli to communicate thephysiological effects on perception is very similarto the stress response modeling conceptpresented in this paper.

In addition, flight simulation training providesinstances that further support this idea. Forexample, Microsoft's Combat Flight Simulator 3, aPC-based flight simulation application,incorporates G-force effects such as visiondegradation and blackout. It recognizes thesignificance of these effects by making G­tolerance a criteria for pilot profile selection andskill point allocation [16]. Other simulatorsincorporate similar blackout simulationcapabilities, such as Aero-Elite for PlayStation 2,Falcon 4, and Aces High for PC.

G-force blackout modeling is a controversialaspect of flight simulation. Critics claim the modelsare not accurate and thereby detract rather thanadd to realism [17]. Supporters respond byhighlighting the unrealistic nature of a pilot who isnot affected by any level of G-Force (while insome cases the non-player character opponentsare affected by G-force). This school of thoughtmaintains that some representation of G-Forceeffects is better than none when the end goal is tocause the pilot to discontinue high-G maneuvers[18].

5.0 CONCLUSION

While using physics models to simulate the effectsof environmental stimuli are a common way toutilize technology in training, examples of similarlymodeling human responses to external stimuli arerare. However, it appears possible that thisapproach might serve some benefit to combatmedics who might experience and be confused bythe effects of stress in real life situations by

providing them with the knowledge of what theseeffects are and how these effects can hinderperformance. This promises to be an effectivemethod for addressing the non-training focuselement of stress in PC game based training.

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