2
The Infantry Population

The Land Warrior System has the potential to significantly alter traditional infantry roles, functions, relationships, and employment concepts. Such changes will affect both personnel selection and soldier performance. In this chapter we examine the criteria used by the Army to enlist infantry soldiers, the functions of infantry training, and the implications of infantry cognitive capabilities and anthropometrics for design of the Land Warrior System. We describe minimum requirements rather than the average because, ultimately, the designer's equipment must be usable for all who qualify for enlistment.

PERSONNEL SELECTION

Soldiers are recruited from the general population in accordance with prescribed cognitive, medical, and physical standards (height, weight, and strength).1 In fiscal 1994 the Army enlisted 68,000 recruits, of whom approximately 63,000 did not have prior service experience. About 10,000 were assigned to the infantry. The Army uses high school degree and the Armed Forces Qualification Test (AFQT), which is a subset of the Armed Services Vocational Aptitude Battery (ASVAB), as criteria for selection. As a matter of policy, the Army can change the distribution of quality within the force by changing these selection criteria. We describe below the infantry population in terms of the selection criteria currently in use.

1  

At one time, the Army administered a strength test (MEPSCAT) to screen recruits: this is no longer done. The minimum height requirement is 60 inches, and the maximum is 80 inches.



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--> 2 The Infantry Population The Land Warrior System has the potential to significantly alter traditional infantry roles, functions, relationships, and employment concepts. Such changes will affect both personnel selection and soldier performance. In this chapter we examine the criteria used by the Army to enlist infantry soldiers, the functions of infantry training, and the implications of infantry cognitive capabilities and anthropometrics for design of the Land Warrior System. We describe minimum requirements rather than the average because, ultimately, the designer's equipment must be usable for all who qualify for enlistment. PERSONNEL SELECTION Soldiers are recruited from the general population in accordance with prescribed cognitive, medical, and physical standards (height, weight, and strength).1 In fiscal 1994 the Army enlisted 68,000 recruits, of whom approximately 63,000 did not have prior service experience. About 10,000 were assigned to the infantry. The Army uses high school degree and the Armed Forces Qualification Test (AFQT), which is a subset of the Armed Services Vocational Aptitude Battery (ASVAB), as criteria for selection. As a matter of policy, the Army can change the distribution of quality within the force by changing these selection criteria. We describe below the infantry population in terms of the selection criteria currently in use. 1   At one time, the Army administered a strength test (MEPSCAT) to screen recruits: this is no longer done. The minimum height requirement is 60 inches, and the maximum is 80 inches.

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--> Cognitive Entry Requirements The ASVAB is a basic tool for recruitment and selection in the military. It is composed of 10 subtests: General science (GS), Arithmetic reasoning (AR), Word knowledge (WK), Paragraph comprehension (PC), Numerical operations (NO), Coding speed (CS), Auto shop (AS), Mathematics knowledge (MK), Mechanical comprehension (MC), and Electronics information (EI). Verbal ability (VE), which is considered an eleventh subtest, is a composite of word knowledge (WK) and paragraph comprehension (PC). These subtests are combined in various ways to form the Armed Forces Qualification Test, which is used for enlistment screening and job assignment. Each service establishes its own composites of the ASVAB subtests to satisfy job structure and mission requirements. Applicants are classified in a military occupation by using the composites to predict success in initial occupational training schools. The Army composites from the ASVAB subtests correspond to 10 aptitude areas: Combat (CO), Clerical (CL), Field Artillery (FA), General Maintenance (GM), Motor Maintenance (MM), Operator and Food (OF), Electronics (EL), Surveillance and Communications (SC), Skilled Technical (ST), and General Technical (GT). Scores on the AFQT range from 0 to 100. The average is 50 and the minimum acceptable score is 10. Test results are divided into five test score categories: I, II, III, IV, and V, and III is further divided into IIIA and IIIB. Categories I through IIIA represent the upper half of the recruit population. Anyone scoring in category V is prohibited by law from entering the armed services; federal law also restricts the number of category IV recruits to no more than 20 percent of the

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--> TABLE 2-1 Distribution of Scores on the Armed Forces Qualification Test (AFQT) AFQT Category Scores Reading Grade Level General Ability Percent of U.S. population I 93-99 12.7-12.9 Very high 8 II 65-92 10.6-12.6 High 28 IIIA 50-64 9.3-10.5 Average (top) 17 IIIB 31-49 8.1-9.2 Average (bottom) 17 IV 10-30 6.6-8.0 Low 21 annual enlistees. The AFQT categories and what they mean in terms of reading grade level and general ability are shown in Table 2-1. The Army sets quality targets both for overall enlistments and for each of its career management fields. In 1994 the Army-wide AFQT targets were 67 percent I-IIIA, 31 percent IIIB, and 2 percent IV. For the infantry, the targets were 64 percent I-IIIA, 33 percent IIIB, and 3 percent IV; the infantry actually achieved approximately 68 percent I-IIIA, 28 percent IIIB, and 4 percent IV. The National Guard is not required by law to meet the category IV standard that the active component is required to meet, yet over the last 3 years it has voluntarily met the 2 percent category IV goal. Although a high school degree is used as a selection tool (it is a good predictor of the likelihood of enlistment completion), it is not technically a requirement for enlistment. The competition is such, however, that for all practical purposes it serves as a requirement. In 1982, Congress placed a ceiling of 35 percent on male Army enlistees with no prior service and no high school diploma. In 1994, the Army achieved its goal of 95 percent high school graduates. About 85 percent of the Army National Guard recruits have high school diplomas. Results from the 1992 Youth Attitudinal Tracking Survey (Lehnus, 1994) show declining enlistment rates. As recruiting becomes more difficult, quality may be traded off by adjusting the selection criteria in order to meet goals for accession numbers. Of course, in the private sector the demand for the best and the brightest will continue to rise as well. As the economy and job opportunities improve, the competition for high-quality personnel can be expected to increase. Although it has been rumored that the force is getting older, the facts provided by the Army do not support this notion. The average age of the active force is 20.4 years and has been relatively constant over the last 10 years; no data were gathered on the Army Reserve or the National Guard (information provided by

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--> the Office of the Deputy Chief of Staff for Personnel, HQDA). The number of soldiers for whom English is a second language is likely to increase, according to current and projected immigration trends. It is important to note that, although a high school diploma and ASVAB scores are useful measures of quality and have been shown to correlate with performance in military jobs (Wigdor and Green, 1991; Green and Mavor, 1994), additional screening criteria are needed for selecting soldiers to perform infantry tasks. These criteria and the tools to measure them become even more important as the nature of the tasks become more complex and information-intensive, as they will with the Land Warrior System. Specifically, it is essential to consider the human abilities that will affect soldier performance with the Land Warrior System. Once these are defined, existing selection tests can be identified or new ones developed for measuring these abilities. One effort to examine the abilities required by different tasks was a 1982 Army study using Fleishman's (1975) human performance taxonomy to determine the degree of difficulty associated with performing tasks in 20 new systems (U.S. Department of the Army, 1982). Known as the "Complexity Study," this study was successful in predicting performance and has been validated through staff studies conducted at the Pentagon. Research that builds on these results should be vigorously pursued by the Army. The taxonomy proposed by Fleishman is presented in Table 2-2 as a guide to identifying useful criteria. The challenge is to identify the relationships between the land warrior helmet-mounted display characteristics and the human attributes that correspond to successfully use the system. Relationships between human attributes and situation awareness are presented in Chapter 3. Infantry Requirements The physical requirements for the infantry encompass those for all Army personnel. In addition to the Army entrance requirements, the following specific requirements have been established for the infantry, which is open only to men (U.S. Department of the Army, 1994a): A physical demands rating of very heavy, A specific physical and medical profile, Color discrimination of red and green, Correctable vision of 20/20 in one eye and 20/100 in the other eye, A minimum score of 90 on ASVAB aptitude test for combat, and Formal training under the auspices of the Infantry School (completion of 11 B course).

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--> The physical demands for infantry soldiers include the following: Occasionally raise and carry 160-pound persons on one's back, Frequently perform all other tasks while carrying a minimum of 65 pounds, evenly distributed over the entire body, Frequently walk, run, crawl, and climb over varying terrain for a distance of up to 25 miles, Frequently give oral commands outside at distances up to 50 meters, Be able to hear oral commands outside at distances up to 50 meters, Occasionally climb a rope a distance of up to 30 feet, Frequently throw 1-pound object 40 meters, and Frequently visually identify vehicles, equipment, and individuals at long distances. The specific physical and medical profile refers to functional capacity to perform (as determined by medical personnel) in six areas: Physical capacity: good muscular development with the ability to perform maximum effort for indefinite periods; Upper extremities: no loss of digits or limitation of motion; no demonstrable abnormality; able to do hand-to-hand fighting; TABLE 2-2 Fleishman's Human Performance Taxonomy Cognitive Physical Psychomotor Verbal comprehension Verbal expression Idea fluency Originality Memorization Problem sensitivity Mathematical reasoning Number facility Deductive reasoning Information ordering Category flexibility Spatial orientation Visualization Speed of closure Flexibility of closure Selective attention Time sharing Perceptual speed Static strength Explosive strength Dynamic strength Stamina Extent flexibility Dynamic flexibility Gross body equilibrium Gross body coordination Choice reaction time Reaction time Speed of limb movement Wrist-finger speed Multi-limb coordination Finger dexterity Manual dexterity Arm-hand steadiness Control precision Rate control

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--> Lower extremities: no loss of digits or limitation of motion; no demonstrable abnormality; be capable of performing long marches, standing for very long periods; Hearing-ears: audiometer average level of six readings (three per ear) at 500, 1,000, 2,000 Hz or not more than 30 dB, with no individual level greater than 35 dB at these frequencies and level not more than 55 dB at 4,000 Hz; or audiometer level of 30 dB at 500 Hz, 25 dB at 1,000 and 2,000 Hz, and 35 dB at 4,000 Hz in better ear (poorer ear may be deaf); Vision-eyes: distant visual acuity correctable to 20/40-20/70, 20/30-20/100, or 20/20-20/400; and Psychiatric: no psychiatric pathology; may have history of a transient personality disorder. Accepting less than perfect vision requires that the Land Warrior System must accommodate soldiers who wear glasses. For older soldiers who wear bifocal lenses, this challenge is compounded; optical inserts in the chemical protective mask are not bifocal. Some infantry positions require more use of tactical information systems than others. An example is the special forces sergeant. Individuals who enter this career field do so after they are in the Army. In addition to the above requirements, candidates for this rank and status (which is also closed to women) must meet the following: A minimum score of 110 in general technical aptitude and 100 in combat aptitude; A secret-level security clearance, Completion of a formal Special Forces Qualification Course (SFQC), Other requirements listed in Army Regulation 614-200, and U.S. citizenship. The position of ranger is also likely to make heavy use of complex tactical information, although there is no separate career field for it. Army personnel assigned to ranger battalions are also selected after they are in the Army and must meet very demanding requirements. TRAINING Training is designed to accomplish many purposes, including acquiring technical, leadership, interpersonal, and conceptual skills; improving and sustaining proficiency from individual to enterprise levels; and inculcating values and beliefs. Army training addresses both individuals and groups. Individual training teaches soldiers the basic skills required for individual survival and job performance on the battlefield. Group training prepares soldiers to perform tasks as

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--> part of a team. Most individual and some group tasks are taught as part of basic and advanced individual training, whereas some individual and most group training is conducted in units. In general, training time demands exceed available time to train, so unit commanders set priorities for training time on the basis of their missions' essential task list and assessments of training needs. Demanding and realistic training builds confidence and cohesion. Resource limitations often reduce the amount of training that is provided as part of fielding new equipment. Fielding the Land Warrior head-mounted display may be particularly challenging. Although the fielding teams do a superb job, they only do it once. The unit assumes responsibility for training new personnel that come as a result of normal attrition. As the original personnel and trainers depart the unit, new trainers take their place without the benefit of having the new equipment fielding training. This attrition process combined with the lack of sustainment training results in a loss of knowledge and deterioration in the quality of training over time. This is offset when the new equipment is used in the Army's basic or advanced individual training, such as tanks, artillery, etc. Training on smaller, more numerous items of equipment often takes place within the unit. Embedded training is one means of preventing the deterioration in the quality of the training that may take place. Implications of the Land Warrior System Work by the Army Research Institute has shown that cognitive tasks involving the accurate recall of subject matter with little or no behavioral component (e.g., a pilot preflight checklist) have high rates of skill decay and require more sustained training than other tasks to maintain proficiency. The Land Warrior System will have a large number of this class of cognitive tasks at the leader levels. To the extent possible, the number of these tasks should be minimized. One of the implied outcomes of the Land Warrior System is to increase the speed at which the soldier thinks and acts. In order to achieve this, soldiers at various levels must: (1) Respond to data: give attention to detail, perceive form, recognize and identify patterns, recall rules, and comprehend their environment. (2) Take action based on data: perform quantitative analysis, reason verbally, assess given situations, formulate concepts, plan, and make decisions. (3) Create data: make inferences, formulate and validate hypotheses, and solve problems. All these things must be done to some extent by soldiers at the front. Historically, soldiers were taught battle drills at the individual, crew, fire team, squad, and platoon levels in order to teach them to recognize a situation and react to it. Furthermore, the squad leader leads by example, which makes it easier for soldiers to see what he was doing and follow his example. These techniques have proven successful in improving reaction time and reducing the time needed for problem solving. Learning standard procedures and drills will continue to assist the speed at which the soldier thinks and acts.

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--> In operations other than war, soldiers find themselves in unique situations for which battle drills and standard procedures have not been developed. In providing soldiers with a common perception of the battlefield or other common contextual framework, the helmet-mounted display will facilitate actions that are based on responding to data or taking action based on data. The extent to which it will speed thinking and acting when the soldier has to create data is not so evident. The challenge is to design a training system that will facilitate this outcome. The Land Warrior System will provide new capabilities to the infantry squad; however, the major return on investment is dependent on soldiers doing things differently than they do today. How well the soldier can use these new capabilities will be a function of training. The system will affect how the soldier sees and interprets the visual scene. The changes in the viewing world will be significantly different from what the soldier learned through life experiences. Loss of depth information and resolution, alternative fields of view that are narrower than normal vision, and a dynamic environment will present new challenges associated with object recognition, balance, orientation, and movement. In other words, the soldier's ability to detect threats, move across terrain, and maintain local situation awareness will be affected. Training will be needed to alleviate some of these concerns. The squad leader will face a number of challenges that, although not new in concept, will be new in application and may have training implications: workload management, maintaining 360 degree observation during movement, actions on contact given possible disorientation and changing field of views, maintaining vigilance during slow-tempo operations (overcoming a false sense of capability), squad previsualization training to reduce cognitive workload and attention demands. With regard to the helmet-mounted display, individual training may be required in a number of areas (although the following list is not exhaustive): Equipment operation and adjustment, Symbology training, Map reading, Visual scene cues and interpretation, Alternative techniques for viewing the scene and overcoming attentional narrowing, Data interpretation, Attention switching between the eye viewing the display and the ''ambient eye," Object recognition training in the absence of depth cues, color, shading, texture gradient, poor resolution, etc., Engagement techniques with various sensors, Movement techniques,

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--> Computer skills associated with application software, Maintenance skills to include field expedient techniques, and First aid for motion sickness, blindness, and other temporary maladies associated with system use. Requirements for individual training will be much greater when other systems associated with the Land Warrior System are included, such as the intrasquad voice and data communications, integrated computer/radio/global positioning system with digital maps and overlays, combat identification, multithreat warning devices, medical monitoring, objective individual combat weapon, a thermal/laser aiming device, a microclimate cooling system, integrated/modular clothing and equipment, and an improved load carriage system. Training aids may be embedded into the Land Warrior System, provided as stand-alone devices, some combination of the these two, or, in the worse case, not provided at all. Although embedded training systems can help alleviate many problems, the computer hardware, space, power, system architecture, and additional weight requirements must be considered as part of the total process of system design. Some specific hardware and software features associated with installing and operating an embedded training system include processing speed, access rate, memory, display capabilities, communications, interfaces, menu structures, and the capabilities for collection of performance data. Planning for such a system must include an analysis of the conditions of use (e.g., conducting embedded training for one platoon while another is conducting operations in a combat zone). More significant will be the cost associated with designing and acquiring a fully embedded training system. Embedded training is relatively inexpensive from a hardware point of view, but it is relatively expensive to develop courseware programs. As a result, only small amounts of training courseware are available, and its compatibility with the Land Warrior System is not known. For more in-depth discussion of considerations in the design of embedded training the reader is referred to Army Research Institute (1988); Witmer and Knerr ( 1991). Personnel Performance and Training Research The introduction of the helmet-mounted display and associated capabilities of the Land Warrior System will significantly alter how the soldier views scenes, interprets what is seen, makes decisions, and takes action. Although we have identified some of the performance training implications, many questions for research remain: What design considerations (processing speed, access rate, memory, display capabilities, communications, interfaces, menu structures) will be affected by training requirements?

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--> What design attributes will mitigate skill decay? How has the need for training evaluation and feedback affected the design? Should display characteristics be different for the trainer and the trainee? If so, how? How much training fidelity is required? How long will it take to gain proficiency? Which human attributes are correlated with successful use of the system? What are the trade-offs between soldier quality and training time? How frequently must training be conducted to sustain proficiency? Will the system help instill confidence and cohesion'? If so, how'? How will the lack of or diminished observation capability affect command and control within the squad'? How will the system help the soldier visualize the battlefield'? How do we know that there is greater battlefield awareness, and does it make a difference in performance at the squad level? What is it that this system provides that facilitates the development of creative responses to a fluid battlefield situation? IMPLICATIONS FOR DISPLAY DESIGN At issue in the panel's work is the compatibility of the proposed new technology with the capabilities and limitations of the target population. Operational requirements specify that "no qualitative or quantitative changes in personnel requirements will result from fielding the land warrior. No new military occupational specialties (MOSs) will be required for operators and maintainers." The Land Warrior System, however, will be providing amounts of information to the individual soldier that may be orders of magnitude greater than are now provided. We discuss below the implications for display design of force quality, physical attributes, soldier acceptance, and performance design. Quality Issues At the leader level, in the infantry there is a higher percentage of lower-level sergeants in category IIIB and IV (approximately 37 percent) and staff sergeants (approximately 41 percent) than in the overall Army force (U.S. Army, Natick RD&E Center, 1994). As a result of retention, there may be sergeants who may not have scored as high on the ASVAB as new recruits. As the propensity of young men to enlist goes down, the challenge to maintain quality will become even more difficult. The implications of this situation are significant. Potentially, the greatest cognitive workload is on the fire team leaders and the squad leaders, who may be the least able to manage it. It is questionable as to whether the majority of the

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--> sergeants of tomorrow will possess the cognitive abilities and skills necessary to operate as envisioned and thereby capitalize on the new capabilities provided by the Land Warrior technology. Approximately 33 percent of the infantry who will use the Land Warrior System will be in categories IIIB and IV. People in these categories can be expected to read at a 7th grade level (see Table 2-1), which is not indicative of speedy information processing (Bowman et al., 1986). Display contrast resolution that does not meet the international standard (ANSI/HFS 100-1988) will negatively affect reading speed. In addition, the display design must accommodate the hearing and vision limitations of current and future soldiers. Historically, in introducing new technology, the Army has experienced unintended effects, such as increases in demands for soldier quality, increased school training time, the need for different skills, and lower levels of equipment readiness. The trade-offs associated with changing personnel selection criteria, quality distribution, and training all have long-term cost implications for the design of the Land Warrior System. For example, the ORD does require that there be no increase to entry level requirements for maintenance MOSs 3 IV and 39E. The maintenance implications on the quality of the force might be offset by contractor provided maintenance. A fully integrated system will require careful Built-in Test/Built-in Test Equipment design to facilitate fault isolation and repair or replacement. Anthropometric Issues One of the important questions that arises is the degree to which the helmet-mounted display system will be adjustable to the individuals who will use it (see Gordon et al., 1988). Will display units be interchangeable among individuals, or are they to be tailored for individual soldiers? What are the implications of individual tailoring for security questions, such as the ability to block or lockout enemy access. The answers to these questions may dictate the approach taken in terms of anthropometric design. Traditional anthropometry is a measurement and classification procedure that allows for the design of individual items to proceed around known physical characteristics of the population sample under consideration (i.e., each dimension of the human body). Such approaches try to provide the best compromise between statistical norms for a group and the unique attributes of individuals. Intelligent design (e.g., modularization) can allow for customization even if the basic configuration is developed on a group basis. The basic considerations of anthropometry and biomechanics are the form and fit of the item under consideration. Some biomechanical factors include the requirement that any head-mounted device must consider the question of weight and prolonged use as they affect muscular fatigue. Likewise, the designers of hand-held devices also need to consider anthropometric factors, especially if data

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--> TABLE 2-3 Head Dimension Measurements for Males (Inches) Head Measure 1st percentile 5th percentile 95th percentile 99th percentile Bitragion coronal arc 12.71 13.07 14.75 15.15 Bitragion crinion arc 11.84 12.11 13.63 13.99 Bizygomatic breadth 5.03 5.19 5.91 6.07 Head breadth 5.48 5.63 6.33 6.5 Head circumference 20.99 21.37 23.37 23.88 Head length 7.09 7.30 8.21 8.40 Interpupillary breadth 2.24 2.31 2.8 2.91 entry is to be provided through keyboard systems. In a military context, it is relevant to consider use of hand-held devices with gloves as an issue that requires careful anthropometric design. Again, in context, voice entry while wearing some form of mask or exclusion garment may prevent optimal use of critical systems. Thus, decisions concerning conditions of use raise any number of questions concerning the fit between the operator and the device. The current target audience description does not cite head dimensions as critical. Given the importance of a comfortable fit to the soldier, the current design specification for 5th to 95th percentile males omits 10 percent of the population. Table 2-3 shows the difference between 5th to 95th percentile and the 1st to 99th percentile on a few dimensions of head measurement. The differences are so small that the needed adjustments should be easy to achieve. Because helmet stability is critical to maintaining a stable image, changes in the requirements seem called for. Given the history of the design of helmets and head-mounted displays for aviators, in which micro-anthropometrics was critical, this change is particularly significant. Although the Land Warrior System is intended for the infantry, others may need it in order provide adequate support to them. It is expected that these personnel would come from the division's support units that are attached to the brigade or battalion task force (artillery, air defense, combat engineer, maintenance, medical, supply and transportation, etc.). These military occupational specialties and the personnel that fill them differ from the infantry population, not least because they include women. From a design fit perspective, this is an important issue. Other future users include the Army National Guard and the Army Reserve, other services, and allied or joint Forces. The anthropometric differences, if any, between these various groups should be assessed.

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--> Potential Soldier Acceptance Soldiers' acceptance of the Land Warrior System displays will be driven by their confidence in their ability to use the device effectively under adverse conditions, the device's attributes, and their views of the need for it in light of everything else that they have to carry into battle. Interviews with the rangers who tested the prototype revealed that they valued three components of the system: squad radio, the thermal sight, and the global positioning system (in unobstructed areas). These components were valued because they provided needed capabilities that were previously not available. Other components were not considered as useful because they did not work reliably, were too heavy or uncomfortable, or did not improve performance. Despite the fact that certain problems clearly biased the test personnel, they were clear about what they thought added value. These data are primarily anecdotal, based on experiences in a preliminary, field demonstration.2 The results of a series of interview following each phase of the demonstration can be found in Salter (1993). A soldier's confidence in a new system is a function of his proficiency, which is in part determined by how much training he has received and the complexity of the system. These factors are interrelated. The more complex the system, the more training a soldier will need to gain and sustain proficiency. Sufficient training is often not provided, for reasons of limited resources. As a result, soldiers require a longer period of time to gain confidence in a system, if ever. Research by Marshall (1947) established that a large percentage of soldiers do not fire their weapons in combat. If a soldier is not proficient with the system, he will not risk exposure to enemy fire. The Land Warrior System offers a solution to this problem by letting a soldier fire accurately while not exposing himself to enemy fire. At the same time, the rangers reported that battlefield mobility was reduced by the night vision system. The complete and integrated Land Warrior System will be perceived to be complex. When new systems are effective and well used, they can become a crutch without which the soldier or the unit may fail to respond. In the early days of TACFIRE (an artillery tactical fire control system), some artillery unit commanders found that their units would not respond to a call for fire when TACFIRE was inoperative. The personnel had become so dependent on the system that they had lost the ability to fire without it. Overreliance on technology can make a unit vulnerable if field-expedient training is not conducted. Soldiers generally expect that a new system will be effective, reliable, and simple to operate, repair, and maintain; will reduce workload or improve effectiveness; and will fit comfortably. For the infantry soldier, if a new system does not help him shoot, move, communicate, or survive, it may be dropped along the march in order to lighten his load. 2   Personal communication with soldiers at Fort Benning who participated in the SIPE field test.

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--> Many leader tasks may be made easier with the Land Warrior System. For instance, reporting could be done photographically. Although this eases the workload associated with reporting, it may drastically increase the workload for those who receive and must interpret the messages. The new system will also require the mastering of some level of operator and maintenance tasks. The danger is that it creates a demand for information that requires the squad leader to change what he does and how he does it. The impact could affect the survivability or effectiveness of the squad when the leader's attention is not properly distributed. Comfort is an essential ingredient to an infantry soldier who is carrying a heavy load; it usually involves form, fit, weight, and balance. Proper fit contributes to confidence. Conversely, a poor fit leads to frustration and anger. Soldier frustration with the initial prototype was reported to be very high (SIPE). Performance Design Issues Providing remedies to the problems of cognitive or information overload is not easy because of the various factors that affect work and the variations in emotional reaction to a variety of perceived risks, physical demands, and surprise. Technology is not the only driver of cognitive workload and may not be the principal one; communication and coordination tasks are major workload factors. Job tasks not related to a system impose significant workload. There is no doubt that workload will go up as a result of the Land Warrior System because new tasks will have to be performed that have not been performed previously. The question is one of penalties and payoffs. The complex technology and all-pervasive impact of the proposed Land Warrior System on infantry soldiers raises a number of basic issues and design considerations. The proposed concept also raises doctrine questions about the autonomy of the individual soldier and about current individual skills and training requirements. The requirement that no qualitative or quantitative changes in personnel requirements are to result from fielding the Land Warrior System (U.S. Department of the Army, 1994) will be an engineering design challenge. Contractors will have to translate this requirement into engineering criteria. For the helmet-mounted display, human factors engineers will want to know about user work requirements associated with field of view, field of regard, resolution, polarity, contrast, and brightness. They will also want to know about soldier ability requirements, such as spatial orientation, perceptual speed and accuracy, visual acuity, division of attention, and eye dominance. Design engineers will want to know system requirements, such as the required field of view, the mean time between failures, and how much accuracy is required. The software programmer will want to know what information is required and when, the required rate for updating data, the required refresh and update rate of the display, the definition

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--> (pixel by pixel) of symbols, and what control mechanisms accomplish what actions. Engineering psychologists will be concerned about degraded stimulus conditions, multiple input channels, pattern recognition, attention allocation and control, and individual differences. Answers to these questions are contingent on the tasks performed, the conditions of performance, the measures of effectiveness used, and the level of proficiency required (Zubal et al., 1990, 1993). Assumptions will be made to answer many of these questions. The questions warrant research in order to establish meaningful threshold values and conditions under which those values are valid. CONCLUSIONS Ultimately the success or failure of the Land Warrior System will depend on the individual soldier. There is a broad range of individual differences in the youth population and large variances around specific cognitive, physical, and psychomotor measures. Historically, personnel selection and soldier training have been used to mitigate this naturally occurring variance. Effective personnel selection requires knowledge of the human attributes that correlate with successful performance. For the Land Warrior System, little is known about the relationship between design attributes, human attributes, and successful performance. Training time is limited. Embedded training solutions can assist if the hardware and software requirements needed are considered in the specifications for computer memory, processing speed, input and output devices, display characteristics, and system architecture. The current space, weight, and power constraints may restrict the effectiveness of an embedded training solution. New equipment must fit properly and comfortably if soldiers are to use it willingly. Careful consideration needs to be given to ensuring that the design meets the anthropometric and biomechanical requirements of the user population. In the case of the helmet-mounted display, comfort and stability are dependent on design. The fit of the helmet may provide an unstable platform for the dismounted infantry soldier; this issue warrants attention. How to suppress the vibration in a helmet-mounted display that is caused by walking is also a question for research and design. The amount of information that the Land Warrior System will provide to the individual soldier may be orders of magnitude greater than the information now provided. The profile of the target audience shows that a large number of potential infantry squad leaders are in the lower cognitive categories of military personnel and can be expected to read at a 7th grade level. Their ability to perform successfully needs to be closely evaluated. The increased cognitive burden is likely to be placed on the two least experienced leadership positions in the platoon-the squad leader and the platoon leader. People who can work effectively with a rapid flow of information in a high stress environment, in which decisions are made with less than full information,

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--> must be able to quickly determine the relevance and importance of the information sent or received. The needed attributes include adaptability, tenacity, the ability to learn quickly from experience and to work as a team, innovativeness and resourcefulness, cultural awareness, and tolerance. Some of the more interesting research questions in the area of personnel selection include: Which human characteristics (cognitive and non-cognitive, physical, psychomotor, etc.) are related to and predict success with Land Warrior? What tests and techniques can be used to select Land Warrior users based on temperament, values and attitudes? Will existing tests predict successful or superior performance? What impact will the LWS have on squad leader selection?