Microwaves
and Behavior

DON R. JUSTESEN

Laboratories of
Experimental Neuropsychology,
Veterans Administration Hospital,
Kansas City, Missouri

complication notwithstanding, the layman's interest in electrobiology is wellattested by the substantial volume of the popular literature; but the strangeand often conflicting claims that appear are equally an attest to a relatedtruth: Science is sorely lacking in an understanding of basic electrobiologicalmechanisms. Moreover, the absence of a satisfactory theory of the role ofintrinsic electrical events in uni- or multicellular organisms puts a heavyepistemological burden on those who would explain how an organism reacts toelectromagnetic fields of extrinsic origin. With the possible exception ofmammalian photoreception, which is better understood anyway as a quantummechanical process than one involving electromagnetic wave activity, there arefew basic data on the biological response to exogenous electromagnetic fields.The hard data that do exist - those vindicated by independent experimentalconfirmations - are without exception correlative or descriptive. Many of thefindings are of interest to the psychologist, however, not only because behaviorhas often been the end point of successful electrobiolocical experimentation,but also because psychologists have played important roles in these researches,particularly in the development of methodology and instrumentation.

In this essay, I summarize some contributions by experimental psychologiststo the biological study of radio-frequency electromagnetic fields, especiallythe "microwaves." But first the reader should be acquainted with a fewfundamentals of wave theory and provided with a synopsis of pertinent historical

Figure 1. Componentsof the electromagnetic spectrum. Frequencies are incycles per second (hertz, Hz) are shown in parentheses.(Abbreviations: D-C, direct current or zero Hz; G, giga-= 10⁹; K, kilo- = 10³; M, mega- = 10⁶; and t, tera-= 10¹².)

developments. The reader who disdains technical discussions may wish to skip thenext few paragraphs, but will probably be rewarded by a better understanding ofthe materials that follow if he or she opts to read them.

The microwave portion of the electromagnetic spectrum includes the emanationsof radars, television, and short-wave radio, The microwaves range in frequencyfrom a few to several thousands of megahertz (MHz). In in vacuowavelengths, the microwaves range from a few meters to about a millimeter. Therelation of the microwaves to the other components of the electromagneticspectrum is shown in Figure 1. My review of data stops short of the radiationsof the infrared spectrum and of the solar and cosmic radiations that lie beyond,but I am not drawing an altogether arbitrary line. While absorption ofelectromagnetic energy of any wavelength translates to and results in anincrease of kinetic energy in the biological target, the photon energies ofradio-frequency radiations are vanishingly small. Not so of radiations of higherfrequency. The ineluctable product of the multiplication of frequency byPlanck's universal constant, photon energy, becomes a potent biological factorat higher frequencies. Correlated with the magnitude of photon energy is theprobability that a radiation will ionize the atoms of the absorbing target. Thedisplacement of electrons from atoms, the crux of ionization,creates additionalelectrical charges within and among, molecules thereby posing distinctbiomolecular hazards - distinct, that is, from the heating of body tissues thatresults from a moderate increase of kinetic energy. Stated another way, atdensities that are low in terms of available kinetic energy, X- andgamma-radiations are like cool but deadly bullets compared to the benign ripplesthat bathe the the organism on exposure to commensurate densities of microwavesand other radio-frequency the energy. On the other hand, exposure to highdensities of radio-frequency energy is hazardous and can result in excessiveheating. Witness the potato that bakes to bursting in a microwave oven in lessthan four minutes!

A major factor that distinguishes the biological response to radiation bymicrowaves as opposed to radiation by infrared and ultraviolet energies is thatthe latter are absorbed or scattered near the

surface of a target. Unscattered microwave energy penetrates much moredeeply. If a 1,000-MHz microwave energy is incident on the head of a humanbeing, a significant portion of the energy will penetrate the skull and becaptured by tissues of the brain. One of the hazards of microwave energy is thatthe warning sensations of warmth so readily produced by infrared energy throughstimulation of surface receptors may not occur to exposures to fairly highdensities of microwave energy until thermal damage has resulted.

The mechanism of microwave heating of biological materials is fairly wellunderstood and derives from two electrophysical properties of water. First, themolecule of water is polarized; it carries a charge that differs over itssurface. The result is an electrical dipole, a molecule that reorients when anexternal electrical field is impressed on it, even as bits of paper areattracted to or repelled by an electrostatically charged rod. Water's secondproperty is a high molecular viscosity, or what is technically termed a lengthyrelaxation time. If its relaxation time is short, a polarized molecule canreorient itself with ease in an oscillating electrical field. Molecules of waterare unable to orient and reorient completely in a rapidly oscillating electricalfield, and so their high viscosity results in "molecular friction"; much of themicrowave energy incident on a biological target can therefore be "lost" ordissipated as heat.

The amount of radio-frequency energy absorbed by a target is a positivefunction of the target's electrical conductivity, a negative function of itsdielectric constant, and to complicate matters, both the conductive anddielectric character of biological materials are frequency- and temperature-dependent. The wave conformation of radiated radio-frequency energy is also avariable that controls absorption; the electric field is at right angles to themagnetic field, and both are at right angles to the line of propagation of theelectromagnetic wave. Energy will couple to a biological target either from theelectric or from the magnetic field, but the amount coupled will change asfunctions both of the relative wavelength and of the relative geometry of thetarget with respect to the vectors of the electric and magnetic fields (seeFigure 2).

The quantity of kinetic energy in a propagating electromagnetic field isreckoned by Poynting's vector and is technically termed "power flux density."This density is the quantity of energy that flows in time through a measuredplane of space.

The quantity of energy is determined by the densitometer and is scaled interms of watts per square meter (W/m²) or watts per square centimeter(W/cm²). A rough rule of thumb for estimating absorption ofradio-frequency energy can be applied to the case in which the physicaldimensions of a biological target are large with respect to the wavelength ofthe radio-frequency energy that is incident on it: Approximately half of theenergy is absorbed and the remainder is scattered. Another rule of thumb applieswhen the physical dimensions of a target are much smaller than the wavelength ofthe incident energy: The target becomes electrically translucent or transparentand little or no energy is absorbed. As the physical dimensions of a biologicaltarget approach the wavelength of a radio- frequency radiation, an extremelycomplex scattering function occurs, a succession of valleys and peaks, andeither very little or a great deal of energy is absorbed. Maximum absorptionoccurs at and defines resonance and may exceed the nominal amount of energy thatis incident on the target. At resonance the effective electrical capture surfacepresented by a "lossy" target of low electrical conductivity may

Figure 2. Idealized schematic representation of radiation of a biologicaltarget in the open or free field, the traditional method of exposing animals tomicrowaves. (In practice, the inside surfaces of a laboratory are covered withenergy-absorbing material that prevents reflection of energy to the target. Theanimal is shown in restraint - necessary, unless the subject is anesthetized,because changes of body geometry will alter the capture-surface exposed toradiations. The H and the E, respectively, refer to the magnetic and electricvectors of a plane wave, transverse field; the flow vector [or line ofpropagation] is depicted by arrows that point to the animal.)

be greater than its physical capture surface area by an order of magnitude(Anne, Saito, Solati, & Schwan, 1961).

Brief Scientific and PoliticalHistory of Radio-Frequency Studies

The history of behavioral and biological experimentation on radio-frequencyenergy is a spotty chronicle that began in the 18th century'when Luigi Galvaniobserved that the isolated leg of a frog would twitch upon brief activation of aremote spark-gap transmitter (see Presman, 1970, p. 3). Much later, a few yearsbefore the turn of the 19th century, Jacques d'Arsonval (1893) radiated intactmammals with radio-frequency energy and recorded both physiological and grossbehavioral reactions. d'Arsonval's observation of elevated temperatures in hisradiated animals marked the beginning of diathermy, the medical term forheating of tissues by radio-frequency energy. Nearly half a century passedbefore the first semblance of concerted investigative activity began - this forthe greater part in the Soviet Union, where a number of investigators, many ofPavlovian persuasion, began to probe for behavioral and biological effects ofexposure to radio-frequency fields. The researches by Soviet and other EasternEuropean investigators through 1966 have been well summarized and synthesized byPresman (1970), the distinguished Soviet biophysicist.

The interpretive thrust of the eastern Europeans' studies of animals and ofcase histories of human beings employed near industrial or military sources ofradio-frequency energy is that chronic exposure to microwave radiations resultsin a neurasthenic syndrome. Headache, fatigue, weakness, dizziness,moodiness, and nocturnal insomnia are typically reported symptoms (cf. Marha,1970; Tolgskava & Gordon, 1973).

Concerted biological investigations of radio-frequency energy first gotunderway in the United States during the middle 1950s, largely through the aegisof the Department of Defense. This joint effort by scientists, who weresupported by all three military services, faltered and died in the early 1960sfor want of sustained funding (cf. Susskind, 1970). The impetus for arenaissance of research activity in the United States occurred in the late 1960sbecause of political events in the Soviet Union. The interpretation ofbiological data from the so-called Tri-Service studies (see, e.g., Peyton,

1961) had been at variance with the Soviet's in terpretation - American rats anddogs apparently did not develop the neurasthenic syndrome, even after intenseradiation by rrucrowaves in the laboratory. Many American servicemen andtechnicians who worked in proximity to radar and other radio-frequency deviceswere examined by physicians, but to my knowledge reliable evidence of thesyndrome was never reported in the United States. Indeed, the clear implicationof the majority of the experimental and case data reported by U.S. investigatorshas been negative for all but simple heating effects. What triggered a renewedout-pouring of support for research on microwaves, once again spearheaded by theDepartment of Defense, was described by Jack Anderson (1972) in his syndicatedcolumn in the Washington Post. Reading like the scenario of a novel byIan Fleming, the column related how the U.S. Embassy in Moscow had been buggedclandestinely for several years by the Soviets, who had presented AmbassadorAverell Harriman in 1945 with a handsomely carved Great Seal of the UnitedStates. An electronic bug was in the seal, and the seal was in a room whereprivy conversations among U.S. officials were supposed to take place. Theseconversations were actually overheard by the Soviets over the next seven years;however, a check by U.S. security experts in 1952 revealed the bug andsubsequently brought forth additional experts who made periodic inspections forpresence of other electronic eavesdropping devices. During one such sweep inMoscow in the early 1960s, it was discovered that the Soviets were directing,beams of microwave energy at the U.S. Embassy.

American intelligence agents were understandably curious, but they did notwant their Soviet counterparts to know that the microwave bombardment had beendetected. Enter the Advanced Research Projects Agency (ARPA), an arm of theExecutive Office that specializes in getting fast answers to far-out questionsthat may bear on national security. Agents for ARPA contacted Joseph C. Sharp,former director of research in experimental psychology at the Walter Reed ArmyInstitute of Research, and an electronic engineer Mark Grove, who began to puttogether at Walter Reed what is now one of the best equipped laboratories in theUnited States for studying, biopsychological effects of microwave radiations.Additional behavioral, engineering, and medical scientists throughout the UnitedStates were also brought into the investigation

effort through research contracts. By the early 1970s, ARPA's support ofmicrowave research had largely faded, ostensibly because of the enactment of theMansfield Amendment. The fiscal slack has since been picked up by the threemilitary services by the Bureau of Radiological Health of the Food and DrugAdministration, and by the Environmental Protection Agency. In spite of muchinvestigative activity supported by these agencies and the recent convening ofseveral international symposia on microwaves (see, e.g,. Cleary, 1970; Czerski,1974; Tyler, 1975), the Soviet's motives in radiating the U.S. Embassy havenever been clarified. One speculation is that the Russians were doing it to"bug" the United States, not in the sense of surreptitious surveillance, but tofrustrate the U.S. military's curiosity. Jack Anderson suggested that theSoviets may have been trying to induce a neurasthenic syndrome in Americanembassy officials.¹ I discount this possibility. But it should benoted that Soviet officials voiced suspicions that minions of Bobby Fischer mayhave bombarded Boris Spassky with microwaves, thereby causing the latter to losehis championship in their famous chess match (Wade, 1972). Recently reportedinvestigations by Soviet scientists (see Czerski, 1974) have convinced me of thesincerity of their belief in the neurasthenic syndrome, but the bases for thediffering convictions of Soviet and U.S. scientists about the syndrome and otheralleged hazards of low-density microwave radiation are yet to beresolved.

Impact by Psychologists

One of the American pioneers of microwave research Allan Frey (see, e.g.,Frey, 1961, 1965; Frey & Messenger, 1973), a free-lance biophysicist andengineering psychologist. Frey's major accomplishment was discovery or at leastconfirmation and dissemination of one of the more intriguing data that linkmicrowaves and behavior. Human beings can "hear" microwave energy. The averageddensities of energy necessary for perception of the hisses, clicks, and popsthat seem to occur inside

¹Jack Anderson mentioned that the subject of the microwavebombardment of the U.S. Embassy in Moscow was on the agenda when PresidentLvndon Johnson met Soviet Premier Aleksei Kosygin at the Glassboro SummitMeeting in June 1967. One informant told Anderson that Johnson personallyrequested Kosygin to order a halt to the radiation of the Embassy.

the head are quite small, at least an order of magnitude below the currentpermissible limit in the United States for continuous exposure to microwaves,which is 10 mW/cm².

To "hear" microivave energy, it must first be modulated so that it impingesupon the "listener" as a pulse or a series of pulses of high amplitude. At firstspurned by most microwave investigators in the United States, the radio-frequency hearing, or Frey effect, was repeatedly dismissed as an artifact untilbehavioral sensitivity to low densities of microwave energy was demonstrated inrats in an exquisitely controlled study by Nancy King (see King, Justesen, &Clarke, 1971). Shortly after the completion of the study and its informaldissemination via the invisible college, the skeptics began to appear inappropriately equipped microwave laboratories in the United States with requeststo "listen to the microwaves." A majority was able to "hear" the pulsedmicrowave energy, thereby belatedly confirming the claims made by Frey fornearly a decade.²

Recent work reported by Foster and Finch (1974) suggests that the Frey effectmay be a thermohydraulic phenomenon. The authors suspended a microphone in acontainer of water that was radiated by pulsed microwaves at low-averageddensities of energy. The microphone delivered signals to an amplifier, the audiooutput of which was not unlike that "heard" by directly radiated human subjects.Since water changes density as its temperature is altered, the minusculethermalizations produced in it upon absorption of the pulsed microwaves weresufficient to initiate small but detectable changes of hydraulic pressure.

Sonic transduction of pulsed microwaves at low-averaged densities has beendemonstrated by Sharp, Grove, and Gandhi (1974) in materials lacking in

²There is irony here worthy of parenthetical comment. Considerthat subspecies of human being, the experimental psychologist, who distrustsintrospective data so thoroughly that a proposition based on them is consideredhighly suspect until corroborating data are observed in lower animals. The ironyin the present case is that the demonstration of behavioral sensitivity tomicrowaves by a dumb animal does not imply that the animal is having an auditory"experience." I was dubious about the Frey effect until I saw rats react to lowdensities of pulsed radiation; this conversion occurred despite my being one ofthe sizable minority that cannot hear microwaves under direct radiation. Theother side of the coin of paradox is exemplified by a colleague, a confirmedcynic, who, while being irradiated in my presence, said, "Well, I can hear the<censored> microwaves, but I still don'tbelieve it!"

water, for example, in carbon-impregnated plastic and in crumpled sheets ofaluminum foil. Even subjects who cannot hear microwaves when directly radiatedby them can readily perceive clicking sounds when a piece of energy- absorbingmaterial is interposed between the head and a radiator of pulsed microwaveenergy. Oddly enough, the mass of the interposed material does not seem to betoo critical; I successively used smaller and smaller pieces of material assonic transducers until it was necessary to impale tiny pieces on a toothpick,yet the clicking sounds induced in the material by microwave pulses were clearlyaudible to me.

The demonstration of sonic transduction bated and unresolved question ofmicrowave energy by materials lacking in water lessens the likelihood that athermoacoustic transduction probably underlies perception. If so, it is clearthat simple heating as such is not a sufficient basis for the Frey effect; therequirement for pulsing of radiations appears to implicate a thermodynamicprinciple. Frey and Messenger (1973) demonstrated and Guy, Chou, Lin, andChristensen (1970) confirmed that a microwave pulse with a slow rise time isineffective in producing an auditory response; only if the rise time is short,resulting in effect in a square wave with respect to the leading edge of theenvelope of radiated radio-frequency energy, does the auditory response occur.Thus, the rate of change (the first derivative) of the wave form of the pulse iscritical factor in perception. Given a thermodynamic interpretation, it wouldfollow that information can be encoded in the energy and "communicated" to the"listener." Communication has in fact been demonstrated. A. Guy (Note 1),skilled telegrapher, arranged for his father, a retired railroad telegrapher, tooperate a key, each closure and opening of which resulted in radiation of apulse of microwave energy. By directing the radiations at his own head, complexmessages via the Continental Morse Code were readily received by Guy. Sharp andGrove (Note 2) found that appropriate modulation of microwave energy can resultin direct "wireless" and "receiverless" communication of speech. They recordedby voice on tape each of the single- syllable words for digits between 1 and 10.The electrical sine-wave analogs of each word were then processed so that eachtime a sine wave crossed zero reference in the negative direction, a brief pulseof microwave energy was triggered.

By radiating themselves with these "voice modulated" microwaves, Sharp and Grovewere readily able to hear, identify, and distinguish among the 9 words. Thesounds heard were not unlike those emitted by persons with artificial larynxes.Communication of more complex words and of sentences was not attempted becausethe averaged densities of energy required to transmit longer messages wouldapproach the current 10 mW/cm² limit of safe exposure. The capabilityof communicating directly with a human being by receiverless radio" has obviouspotentialities both within and without the clinic. But the hotly debated andunresolved question of how much microwave radiation a human being can safely beexposed to will probably forestall applications within the near future.

The U.S. limit of 10 mW/cm² is actually an order of magnitudebelow the density that many investigators believe to be near the threshold forthermal hazards (Schwan, 1970). There are two camps of investigators in theUnited States, however, who believe that the limit is not sufficientlystringent. In the first camp of conservatives are those who accept the Soviet'sbelief that there are hazardous effects unrelated to heating from chronicexposures to fields of low density (< 1 mW/cm²); some agree withMilton Zaret (1974), a New York ophthalmologist, who holds that severelydebilitating subcapsular lesions of the eyes may develop years, even decades,after exposure to weak microwave fields. Others tend to reject the notion thatweak microwave fields produce this anomalous cataract, because of lack ofsubstantiating, evidence from the clinic or the laboratory (Appleton &Hirsch, 1975). But these conservatives are possessed of a vague unease simplybecause of the Soviet's limit of continuous permissible exposure is three ordersof magnitude below that of the United States.³

The othercamp of conservatives tends to reject the possibilityof hazardous nonthermal effects,

³ The Soviet's exposure limit of 10 μW/cm² isthree orders of magnitude below the exposure limit in the United Sates, but adifferent, that is, emission, limit holds for microwave ovens purchasedfor use in the American kitchen. In the United States at the present time, anewiv purchased microwave oven may not emit radiation at a density greater than5 mW/cm2 as measured at a distance of 5 cm from the oven's surface. Auser who stands I m from an oven that emits energy at the maximum permissiblequantity would probably be exposed to a density of only a few microwatts persquare centimeter - this is because electromagnetic energy when radiated from apoint source attenuates markedly as it propagates through space.

but holds that there are thermal hazards even in microwave fields of low-measured density. To understand the qualms of these conservatives, the readerneeds be informed that the data used to establish the current U.S. limit werefor the greater part gathered under highly controlled conditions in thelaboratory with simulated biological targets (see Anne et al., 1961). Hollowglass spheres containing mixtures of fluids that duplicated the net electricalcharacteristics of the contents of the human head were radiated in what istechnically termed the "free field," that is, under conditions in which noreflected energy illuminates the target, only that radiated by the source. Underactual conditions where microwave radiations at fairly high densities areencountered by human beings, for example, aboard ships, in or about aircraft, ornear around-based radars, there are nearly always reflective surfaces that couldreflect additional energy on a biological target. Unfortunately, additionalconcentrations of reflected energy may not be detected by densitometers becauseof their high directional sensitivity. A radio-frequency field that measures lowin density may actually contain significant levels of energy. Such was thefinding in a collaborative investigative venture by the engineer Arthur Guy andpsychologist Susan Korbel.

Guy and Korbel (Note 3) radiated models of rats in a 500 MHz microwave fieldthat, as carefully measured by several densitometers, appeared to have anincident density near 1 mW/cm². Activity levels of radiated rats hadearlier been found to differ reliably from levels of controls after exposures atthis low density (cf. Korbel, 1970; Korbel-Eakin & Thompson, 1965). Guy andKorbel were aware that the exposures had taken place in an electrically shieldedenclosure. Since the shielding created the possibility of undetected reflectionsand concentrations of energy within the enclosure, thermographic studies wereperformed on radiated models. Extremely high concentrations of thermalizedenergy were found, some of sufficient density that they would result in focalburns in the heads and extremities of live animals. The hot spots observed inthe models would be less severe in a live animal because of partial thermalequilibration by the circulatory system; of major interest is that the totalamount of energy absorbed by the models was often much higher than what would bepredicted from the measured density of the microwave field. Guy and

Korbel's data are a clear vindication of suspicions by other, investigators thatthe exclusive use of field density as the independent variable in biologicalstudies of microwave irradiation is an egregious shortcoming (cf. Johnson &Guy, 1972; Justesen & King, 1970).

In 1967, Nancy King and I sought to resolve the problem ofaccurate scaling and dosing of microwave energy in laboratory studies by twomeans. The first was to use the multimode cavity, now widely in domestic use asthe "microwave oven," as the medium for exposing experimental subjects. Thequantity of microwave energy absorbed by an animal in such a cavity can beclosely metered and controlled (Justesen, Pendleton, & Porter, 1961;Justesen & Pendleton, Note 4). Justesen, Levinson, Clarke, and King (1971)transformed the cavity (a Tappan microwave oven)

Figure 3. Plexiglas conditioning chamber located in a multimode cavity.(Microwave energy enters the cavity from the wave guide and is mixed by a slowlyrotating mode stirrer so that it impinges on the animal in the chamber from allangles. A photodetector of the licking response, a liquid feeder, and a specialgrid for presenting electrical shocks to the feet provide for operant and/orrespondent conditioning of an animal during radiation. A steady stream of cooledair flows from an air duct into the cavity and the chamber and out of smallholes in the door of the cavity. Temperature in the chamber is monitored via anelectrically shielded thermistor.)

into an operant and respondent conditioning chamber that permits radiationduring behavioral testing. The achievement of controllable energy dosing ofanimals in behavioral experiments was something of a challen-e because we had todesign and incorporate a special response-detection and payoff system foroperant conditioning that would not interact with the microwave fields insidethe cavity's conditioning chamber (King, Justesen, & Simpson, 1970). Asimilar challenge, that of providing, a noninteractive source of aversiveelectrical stimulation for Pavlovian conditioning, was met by the design andincorporation of a faradic shocking device (Justesen, King, & Clarke,1971).

We sought to cope with the energy-scaling problem by using calorimetricdosimetry; whereas the densifometer measures energy in proximity to a target,the calorimetric technique provides estimates of the amount of energy actuallyabsorbed by a biological target (cf. Justesen & King, 1970; Justesen,Levinson, Clarke, & King, 1971; Justesen, Levinson, & Justesen, 1974).Taking our lead from the ionizing radiobiologists, we proposed a conventionbased on absorbed energy per gram unit of mass. Because of the high-photonenercies of X- and gamma-rays, the rad - the standard unit of absorbed dose ofionizing radiation - is couched in relatively minuscule terms of only 100 ergsper gram. For the microwaves with their low-photon energies, we proposed that10⁷ ergs or one joule per

Figure 4. Schematic diaaram of a twin-well difference-calorimeter developedat the Battelle Laboratories. (Highly precise measurements are made of thequantity of microwave energy absorbed by models or bodies of radiated animals. Areference or nonirradiated target is placed in one well, a radiated target inthe other well; the difference in thermal loading is then detected by sensitivethermocouples.)

gram (J/g) serve as the dosing unit of total ab-sorbed energy. Since thejoule per second is the time-complexed quantity of energy that defines the watt,we also proposed that the watt per gram (W/g) serve as the basic unit of rate ofdosing.

To estimate the amount of energy absorbed by an animal in a microwave field,we employ simple thermometry, the measurement of elevation of temperature(Δt) in phantom models by precision electronic thermometers. Inthe multimode cavity, the Δts of cylindrical models of water canprovide an estimate within 10% of the energy actually absorbed by small animalsof equivalent mass (Phillips, Hunt, & King, 1975). The quantity of energy inwatts is readily calculated from the Δts and is then divided by,the animal's weight in grams to yield the rate of dosing. A 300-g rat underpulsed 2,450 MHz radiations has a dosing-rate threshold of perception near .5mW/g (King et al., 1971). To place this value in a meaningful perspective, onecan compare it to the rat's ambient rate of energy production throughmetabolism, which is near 10 mW/g in a standard environment. A 60-sec exposureof a 300-g animal that is absorbing microwave energy at a rate of .5 mW/g wouldmaximally increase its averaged body temperature by .01°C.⁴

The calorimetric dosing, method is a substantial improvement for experimentalpurposes over the traditional scaling technique in which the measured density ofenergy as incident upon an animal is used directly as the independent variableor else to estimate (via rough rules of thumb) the deposition of energy in theanimal. Where errors of measurement greater than an order of magnitude arepossible and, indeed, probable, with the traditional, densitometric methods ofscaling, the areas calorimetric technique reduced the error to less than 10%. Apsychologist, E. Hunt of the Battelle

⁴The maximal rise of temperature is stipulated for theanesthetized animal. The awake, physiologically intact animal that isexperimentally naive to radiation at detectable densities may exhibit anelevation of bodv temperature that is greater than that solely attributable toheating by microwaves. Apparently, the emotional activation induced by novel (ornoxious) stimulation is associated with metabolic activation, and thusconcomitant endogenous heating, which adds to the total thermal loading of aradiated animal (justesen, Note 5). Unless there is a compensatory rise in rateof heat dissipation, an emotionally stressed animal may succumb fromhyperthermia during radiation treatments that are not mortal for an habituated,unstressed, or anesthetized animal (Justesen. Levinson, Clarke, & King,1971; Justesen et al., 1974).

Laboratories, took the lead in squeezing the last eliminable error from thedetermination of energy dosing. (see, e.g., Hunt, King, & Phillips, 1975,Phillips et al., 1975) developed a special twin-well calorimeter (Figure 4) intowhich suitable models or carcasses of a control and an irradiated animal areplaced immediately after microwave treatments. Differential calorimetry is thenused to measure the amount of energy absorbed by the radiated target, either inthe multimode cavity or in the free field. When quantities of absorbed energy athigh dosing levels were subsequently equilibrated for live animals in the cavityand in the free field, Hunt and his colleagues observed that death rates weremuch higher from exposures in the free field. One would expect this differencebecause the animal in the cavity is absorbing energy that is incident from allangles while the animal in the free field is illuminated unidirectionally(calling to mind the discomfiture of the naked child in a cold room as he standsin front of an overheated potbelly stove).

The comparisons by Hunt and his colleagues involved mice and rats inrestraint under irradiation by moderate to high densities of microwave energy.The bodily restraint, which is used in the free field to maintain constancy ofenergy dosing, can interact as a stressor with microwave-induced hyperthermia toincrease morbidity and mortality (cf. Justesen,, Levinson, Clarke, & King,1971; Justesen et al., 1974). Comparisons of cavity and free-field exposures ofrestrained subjects at lower densities of enerhy would be desirable on twogrounds: first, if the energy incident upon an animal in the free field is nottoo intense, the gradient of temperature between exposed and unexposed areas ofthe body will be reduced by convective dispersion of heat by the blood stream;and second, the study of operant and respondent behaviors can best be realizedin animals undebilitated by excessive heating. The appropriate comparison ofbehaviors of subjects under low to moderate densities of microwave energy hasbeen undertaken by Lin, who trained rats to accept restraint in a body holder(Lin, Guy, & Caldwell, Note 6). Slight movement of the head of a restrainedsubject was possible, and it was this movement that Lin used as an operantresponse. During pretraining, a restrained animal was reinforced with a foodpellet each time its head interrupted a photoelectric beam until respondingduring short daily sessions had stabilized. Then Lin et al. irradiated theanimals

with 918 MHz microwaves in the free field first at low densities and then atsuccessively increased densities until the head-moving operant extinguished. Theabsorbed-energy dosing rate at the threshold of extinction was near 8 mW/g, avalue that agrees closely with that reported for cornparable measures on ratsexposed in the multimode cavity by Justesen and King (1970) and by Hunt et al.(1975), One may surmise, at least tentatively, that the behavioral andbiological response to exposures in the cavity and in free field are more likelyto be comparable at low densities of radiation and increasingly divergent atincreasingly higher densities. One may also surmise that free-field exposures tomicrowave energy, insofar as they produce unevenness of heating in anexperimental animal, are much more likely to be thermally stressing in thepsychological sense. The quintessential characteristic of psychologicallyadequate stimulation is change either temporally or spatially. In the absence ofchange, or in the stead of change that occurs too slowly, even intense energymay not be behaviorally stimulating. Scripture (1899, p. 300) recounted how afrog never so much as twitched, as the water in which it was immersed was slowlybrought from body temperature to the boiling point. King (1969) recounted asimilar experience with rats long inured of exposures in the multimode cavity tomildly thermalizing radiation. During radiation treatments the animals becameimmobile and appeared to go to sleep. I thought her animals were displaying theneurasthenic syndrome until she measured their body tem peratures and found theywere suffering from something akin to heat prostration!

Epilogue

Focused as it was on methodology instrumentation, this article has skirtedmuch information that relates psychology and psychologists to the biologicalstudy of electromagnetic fields. Among the omissions is the special concern forbehavioral variables manifested by most basic and medical scientists currentlyworking "in the microwave field." Much of this concern is actually homage to thereliability with which behavioral effects have been demonstrated and duplicatedin the radio-biological laboratory. Behavior has become a major "handle" or endpoint in attempts of scientists to get a purchase on the biophysical andphysiological events that occur in the radiated

organism. What these scientists have discovered is that the central nervoussystem is a biological amplifier whose output as manifested in behavior providesa highly sensitive litmus of reactivity to electromagnetic energy. Thissensitivity, particularly the demonstration of the Frey effect, will inevitablygive rise to the question, Are there substantive implications here forparanormal phenomena especially from the vantage of the Soviet scientist forwhom ESP means "electrosensory" (not extrasensory) perception? I am not preparedto answer beyond this caveat: Under optimal experimental conditions, thequantity of microwave energy that is necessary for direct transfer ofinformation to a human being is many orders of magnitude greater, say, than thephotic or acoustic energy associated with a threshold response to visual orauditory stimulation. Perhaps there are electromagnetic receptor systems in usas yet undiscovered with sensitivities comparable to or even greater than thatof the visual and auditory systems. This possibility, however, is bankrupt ofoperational meaning without a corollary demonstration of specificelectromagnetic radiation by the human organism. Without a transmitter, areceiver is useless. Except for an incoherent flux of infrared energies that arebroadcast from our bodies as the residue of metabolism, there are no knownelectromagnetic emissions of sufficient energy to warrant more than the mostguarded of speculations, Not at all a cynic, but very much the skeptic, Iconclude:

ElectroMagnetic receivers we are,
A light-wave we can see;
As E-Memitters our wave fronts are weak,
Hardly enough for ESP.

REFERENCE NOTES

1. Guy, A. W. Personal communication, October 15, 1973.
   
2. Sharp, J. C., & Grove, M. Personal communication, September 28, 1973.
   
3. Guy, A. W., & Korbel, S. F. Dosimetry studies on a UHF cavity exposure chamber forrodents. Paper presented atthe International Microwave Power Institute's Symposium on Microwaves, Ottawa,Canada, May 1972.
   
4. Justesen, D. R,, & Pendleton, R. B. Radiopyrogenesis in animal activity andlearning. Paper presented atthe meeting of the Rocky Mountain Psychological Assodation, Sante Fe, NewMexico, May 1958.
   
5. Justesen, D. R. Theevoked thermal response (ETR): Rediscovery of the marked correlation betweentemperament and temperature.Paper presented at the meeting of the Psychonomic Society, Boston,Massachusetts, November 1974.
   
6. Lin, J. C., Guy, A. W, & Caldwell, L.R. Behaviorial changes ofrats exposed to microwave radiation. Paper presented at the IEEE internationalMicrowave Symposium, Atlanta, Georgia, June 1974.

REFERENCES