Period from February 1) 1967 to October 15, 1967 1. !3un-imary of Progress The previous phase of this study afforded evidence fox a model of the electrodermal response which implied that the recovery limb contained infor- malion of value. An approxii-nate method for obtaining a characteristic measure of this limb, the recovery half-time, was adopted and used for in'-Itial explora- tiori-s into possible applications of the new measure. Results viere very encourag- in- and as a consequence a major effort has since been exerted to%vard the develop- ment of a more refined measure for characterizine, the recovery limb and toward the evalliation of its behavioral indicaeions. At the same time a parallel effort was ,LnainEained to conti--.iue experiments aimed at clarifying the nature of the peripheral mechanism of the response. The follon@,ing surnmarizes progress made in these areas. The subsequent section on Specific Findings (11), details the quantitativ(t da[a of thr,,se items whose analysis has2 proceeded far enou@.,n for reporting. A. R,-rnverk7 Limb imeasure 1. A suoerior manual method was developed for obtaining the time con- st--nt of the recovery limb. Its reliabiliL-1 bet@.veen ;corers and in repzated measures e%ce.:@ds 0.90. 7 f ldate -2- 2. The basis for t@vo automated 5ysceii,-ts for evaluatinp, L:'-tc Eirne cojistant was estab'LisliLd; one of these is an atialog system, Elc other digital. Both a-re relitively simple, 2 3. The discrirti power of Elie new measure as an indicator of scit-nulus situation has been tested on several populations, using the manual method. It successfully distinguished bet@veea severa.1 paired categories of stimulus con- ditioi s with remar@-able reliability. 4. The recovery limb time constant for a given individu--l d2urin,- a standard stimulus situation was found to be characteristic and was correlated with his rate of habituat-'-On to a series of repeated stimuli. Individuals who had a short time constant also tended to have a slower habituation in their electrodermal response to a series of reaction time tests but not to a series cf tones. 5. The variation in tirne constant was examined in a 2population of subje-.ts -@'n which each was exposed to a succession of eight conditions ranging from restin- with eyes closed through a series of simple to complex tasks. A cold pressor test was also included. The Eime constant varied with the situation ill- a characteristic manner, being longest for the rest %ituation and becoming shorter as the task becomes more ir@v2olving. This finding was a consistant one across subjects and was independenc of amplitude. The cold pressor test, althotigh producing high activation, was accompanied by a long time constant (about the;same order as that of spontaneous responses during rest). These results stron-ly supported the interpretation of short time constants as accompaniments of coal directed behavior. 66. 51-iorter time constants were found, as predicted by Ehe model, to be @ssociatcd ,vitli positive skin potent'al responses and with reabeorption responses. 3 - B. Studies of clic Periplieral i\'ICCIIaLliS,-Il 1. A major question regarding the nature of the absorbtion reflex (and presumably, tli@,rcfore of the ori,-riii of the posieive skin potential response believeci'to2 be rela.-ed to it) is whether it depends upon absorption tjlrougli the horny layer, mediated by ttic underlyiii,- epidermis, or upon s@,%,eat duct activitv. An optical device for observinz surface moi Ila-; z ")Dorted the hxnotliesis that reabsorption occurs via the snveat duct. 2. The local potentia2l response (LPR) produced bv stretchine the skin was previously shokvn to contain a fast and a St nt which often respond differently to chanizes in surface conditions. A given variable nay produce either potentiation or attenuation of the LPR in a marwer v;hich defies prediction at this staae, but the variation in amplitude of the experimental site is consistently -reat2er thaa the control and an effect of the surface variable is consequently statistically significant. However, only three ef.Lects are consis@ant in direction of chance: 4:3 a. Reducina surface temt)erature produces an L-icreas,-- in LPR amplitude. b. --@xsa.nguination produces an 2increase in LPR amplitude. c. Ba ckgrourd ncgative electrodermal potential activity produces an L-icrease in LPR amplitude. 3. The striking effecl of the aluminum ion in selectively potentiating the positive wave or! the skin potential response was ucilized as an aid in an attempt to identify which coili-)onent of the biphasic potential response @vas primarilv responsible for the coji(iticcarice cP@LLiic-C i;t rtic c)-,osoii,.a-,ic rcsl)oiise. S;,Icc -t ratfier varilitioii in clicir i7csi)oiisc to local api)licatioil of @'.ICI 37 concordance beL,@@,,een effects ul)on pos!Live potciitial responses @@iid effects upon coii(juctance responsc5 was cxa.-iiiiied. T[ic results Of tl]is Study on 20 z;ubjects raised more questions cliaai ic answered. AltlIOLICrIl pOtClItiatiOn Of the conductance response %%,as correlated2 witli the potontiitiort of t[ic potential response across subjecrs, the as specific relation to S?Ils of nacrative/opposed to positive direction, and Elie relation of polarity of currc-nt flow to do-ree of potentiacion presented a confused picture. .Nloreo%,er, the associated measurements of capacitance and impe2dance revealed no si,-nificant effect of AlCl on these for the -roup as a whole. These results are 3 0 presently undergoing intensive examination and will not be reoorted here. 4. The report of a findin- of s-,@,eat -1,!nds under the nail 2 lindicatino, that these were obsened onlv at the distal tip near the marrrin with the naked sk-Ln. A new method for ipsuring that ............ the nail plate site Njas confined to the center of the nail and for precluding spurious contributions by activity of the reference site demonstrated the L@ollowino,, 2 a. Posicive or negatii,,e potential responses may be observed from the center of the nail plate. b. These are not appreciably influenced (if at all) by tlle applicatioa -of various surface electrolytes. c. Local potential rest)onseq of Iiizli iia.znitude k'all posieix,e) are 3 readily elicited from tl)is same area. d. EXOSO[liatic flail re.@;ilonses stiowinq the t%-r)ical increase iri c,-)nductance are not obser@,ed. Rcsponses sliowing a decrease in resistance are not unusual, but entire records in which the nearby skin is active may sliow none of2 these. They are tliought to rcpresent the vasomotor effect upon cond-uctance n,r)ically seen in the impedance plectivsmogram. The lac@- of covariation betx-.,een ------------- the ILqtang 2 -.2.r@sDonses and the nail pc-tential resd,)nses sug,c,,,ests that tliev rCDresent dif.Lerent. plienc-mena. At this stage it is believed that the nail potential responses because thev correlate highly Nvith skin potential responses TSPR), reoresent a comdonent 2 found in the SPR -,,.,hicli is not of sweat i Zland orizin. C. Study of Bio-Psychological Adaptabilicy Initial exploration of the possibility of uslng the adaptability of autonomic behavior as an index of adaptability of psychological behavior has been started on a 2 population of 60 slb@ects. These wp-re run through a battery of psychological tests and ther. exposed to a behavioral situation which exaniined their rate of habituation to a series of repeated stimuli, their rate of activ@tion from a rest state tj a "..sk state, and their rate of relaxation following the end of the task. Analyses cornpleted to date have shown that indiv2iduals who demonstrate a capacirv to maintair, a @,ii-h degree of appropriate inhibition during motor task, performance also show radid recoven, of electxodermal levels after high activation. NIoreo,.,er, post--,ctivation recoverv to oririnal rest levels for pulse volume and for electroder.'Ilal acti%@irv pro- 3 J, ceed at different rites, and a larcre fraction of the test PODUlation shows a recit)rocal ..... @@4 - C2 rclation bet@veen tllesc t@%vo rates. Adlhk -6- II. Spccific Findinizs A. Becov@u Limb of the Skin Conductance Response 1. inbnual measurement of the recovery li'mb time constant. Gildemeister (1923) and Darrow (1937) bad described the recovery limb as an ex2ponential decay curve. All responses whose recovery linib Ms the same time constant should fall along this curve independent of amplitude as shown in figure 1. In actuality only the first portion of tjiis limb falls upon an exponential slope, since the latter ortion apparently represents a separate component -as described in the p nr,!vious report. Because this second com2ponent may come in at various levels, tl,.e half-time measure previously described is subject to considerable variation in the activitv of the slow comoonent (fio-ure 2). In addition, if a second wave occurs durin- the recovery of the wave in question, measurement of the half-time is often precluded. For these reasons, a method for examining the time constant of the early portion of the recovery l2imb was developed. In this method a transparent template consisting of d family of exponential curves, each having a sli-hcly Ion-er time constant than the one to its left, is slid sideways over the response, its base- line at the level of response onset, tlntil one of th@ calibrated slopes corresponds with the early port-ion of the recovery limb (figure 3). Interpolation is easily accomplished. 4 A reading takes about 7 seconds, and reliability both for repeated measures and ber@veen scores is high (better than 0. 9). If the baseline (during inactive periods) has an appreciable slope, a correction must be applied. This is acccmplished by lowering the baseline of the template to a level half way bet@veen the level of wave onset and the Agh Figure 1. Illustration of variation in apparent shape of responses -iaving same recovery time constant but different ai-nplitudes. Ask cr OQ (!D SD U) 0 fb @3 Figure 3. Nletliod c,; determining recovery limb time constant by template metliod, POPP= -7- level at @%-I-licii it takes on rile slope of @lic restiner base'---=-. In practice this is a siii-iple operation wliicli is not comi-nonly necessary. ings are mandatory %vlicncvcr quantitative treatincnt tirnc- conctint is aLten)r)ted. 2 2. Automatic determination of the time cc--z--:nt. a. Aiialog met[-lod; (1) S inc c the equa tion for a n expor- I cu i-ve is dE Tt- = _ k E Nvhcre E is the voltage, t is time is a rate 2constant which is the reciprocal of the time conL;tE-=. d2F, = -k @K dt cr Yf where Y' and Y" are the first and -c@-:-.id derivatives of the recoveri 2 Lin-u'i with respect to time. Theie :@Lz'--e readily obtained by the use of ope-x,.ational amplifiers as shoN@-- - @r--ure 4. Y' and Y" are fed into a simple division circuit which --,i,,,antan--e of the lo,-ariehmic characteris2tics of a silicon diode H. L. Review of Scientific Instruments 33, 235-233, 1962, 7. -.nfonnation of interest in the oucpi,t will be the negative peaks c-. ----z rate constanc which rilay be .neasured by a digital voltmeter. (2) Another form of th6e exponenc"@-'- -@:--ation, log E k-t + c AglbL clot ico 0 0. IcK 7 1 i %co K 1 y Figure 4. Circuit for obtaining the first and second de@:ivatives (Y' and Y") of the recovery limb. AML AGML suycests that the rate constint can be obtaiiied bv the slope of Olt) log E against time or (!(Ioo- E-:)/,jt, UTnforturaEely titis would be useful only if E rep2resents vottave referrc!c: to final asymptotic level (i.e., to baseline), an arrangemeat w-iich would be com- plicated, if ijideed attainable. b. Di-itti method: An approximate solution for obtaining the rate constant lends it- self readily to analysis by digital voltmeter2 and simple di,-!tat computation. It is based on the fact that exponential decay is essentially a percentage relacion, i.e., in a small increment of .-.!me, the percent recovery is constant regardless of the amplitude chosen. From this it follows that the ratio of the absolute incre- mencs of rec2overy in t@vo successive increm2nts of time is related to the time constant, Thus if recovery is taking place at 5 percent per millisecond, thi recovery rate may be obtained, for example at the 1 volt level, by taking E = 05 x I volt 0500 2 E2 =05 x 0. 95 volt .0475 7Q calculate the rate constant, take I - .0-500 = Os d5 2 .0475 la practice, volta-es are sampled by a digital voltmeter at 3 ,5-tccessive points on the recovery limb, e.g., at 0.82 second intervals, (figure 5) s,,arting 0.5 seconds after peak and the H' TAB Tse A H K AB B HBC -C T 1 Figur2 5. Method for determining time constant of recovery limb by di(Tital measurements. -9- -ippropriate calculacion made cidcr manually or by coiiiputcr. 3. Testing tllc discriniiiiating power of the time constant measure.. The t/2 measure was previously shown to be capable of discriminating be- t%@2,een rest and taskperformtjice and between the response to dn alereing signal and the response to a task, execution signal (for some subjects). The now time constant measure was tested on additional populations and under different conditions. One was a comparison on 3,5. subjects of the time constant associated with the orienting response to a series of tones as compared with that to a series of2 reaction time tests. Figure 6 sho@vs the characteristic acceleration of the recovery limb attendirg the reaction time effort. Figure 7 s-iows the results for the entire population (P < .001). Onlv two subjects failed to show the acceleration. In another evaluation (this one of the power of the t/2 measure) a population of 16 subjects was e-.\posed to a serie2s of moderate li.-ht flashes and their orienting responses obtained. They were then instructed that when the liz-,ht flashed (same light) ttiey were to obser-ve the position of a moving pointer, but to withhold reporting until requested. Thus no motor activity was overtly Lnkplved in tiis perceptual task. Table 1 shows the result 4-id also summari--2es other tests for comparative purposes. All but 3 of the 16 subje(.,ts shonved an acceleration of the recovery limb during the perceptual task,. Another example of the ability of the recovery limb to discriminate is seen in figure 8 which shonys simultaneous recordings from the dorsal (hand) and palmar sur- faces of zv,,o indi'vidual!@.6 The letter 'n indicates an ale-rtin- si-,-ial for a j'oxthcoml-ig RT Figure 6. RecordiTs of responses to a series of tones and a series of reaction time signals, sho%@,ing acceleration of recovery limb during reaction time series. TC 18 1 5 1 2 Goo 9 0000 0 a 7 00 OC--- TONES RT Figure 7. Scatter diagram of recovery limb time constants of responses to tones and reaction time signals for 35 subjects. S E S E 4.9 5.0 2.8 3.1 7.2 5P 3.1 3P 1.8 2.6 -5.7 4.1 2 Figure S. Simultaneous dorsal an3d palmar traces for t@vo different subjects showing recovexy limb time constants of responses to alerting signal (A), spontaneous activiti (S), and reaction time execution signal (E). MEAN CHANGE N MEASURE CONDITION A CONDITION B A to B p 12 12 t/2 R est Aggressive Game -2.3 <.001 5.6 sec 3. 3 sec 41 Yo) 2 16 / 13 t 2 Light Flashes Perceptual Task -2. 3 <.05 7. 9 sec 5. 6 sec (-29 @lo) 35 1 32 t. c. Tones Reocti@on rime -5. 5 <. 001 10. 4 sec 4. 9 sed 53 olo) 0 Table 1. Effect of various stimuius conditions upon recovery limb time constant. reaction tiiiic effort; E is tltc exccution si,@nal and S denotes a spontancous %,,,ave occurrin- during ttic forepcriod. Below these responses are the time constants. In the dorsal trace of the first subject, the time ccnstant of the spontane- ous response is approximately equal to that 2of the alerting response while the execution response has a. tin--c constant of approximately half this length-. Although the absolute levels for the palrcar and dorsal traces are different, tl-ie same relacionships hold. second subject (ri.-ht hand panel) shows a different sort of relation. This subject has a short vime constant in the alertincr response. That of2 the spontaneous response is almost nvice as long. The execueion response for tMs subject has a considerably slower recovery limb than does his alerting response. liere again the palmar responses thou-h of di-fferent absolute value are in the same ratio as those from the dorsal sur- face. These autonomic pattern differences will be e,-Lamined for possible use as an indicator of characeeristic behavior patterns in an individual. Figure 9 exemplifies the application of this measure in the identification of qualitatively different states, despite similarities in resdonse amplitude. In the upper trace a subject is being presented with his first series of reaction time (RT) and word association OVA) stimuli. There was a forewarnina, sional for the reaction time and2 the subject in each case responded to this alerting signal as well as to the execution si- ,,nal. In trace B %@,hich occurred 8 minutes later, the subject has al)plrently habituated to the s.-Ztuation and lias ceased respondinc, to the alerting si,-,nal. ixotice tlie marked slowin- of the recovery limbs, and especia3lly that the response to tl-.e word association, thoug--l of similar amplitude co that Ln A, lias a -reatly differing time constant. RT WA RT RT t-VA RT B Figure 9. Conductance responses to reaction time signals (Rf) and word association (%VA). Traces A and B are taken on the same subject 8 niinutes apart. AML qp 4. Corrzlition r)f i@-i cf)pstl One naturall%r wonders whether t!iis nicasurc which can differentiate between conditions %vitliln a subject independently of rcsl)o2tise amplitude can also differentiate bct%,icen subjects liariiig different behavior patterns in similar situations. To answer this question, the recovery time constants of responses to reaction time efforts were used to characterize the individual subjects. Also determined for each subject was a measure of the rate -of habituation of tl-icir responses eit@er to a series of tone2s or a series of reaction ti-ne efforts as seen in figure 6. The measure of haD .Lt@iation was the quotient of the amplitude of the second response of the series dividedi2@ the third respo_rlse. The larger this ratio, the more rapid the habituation. Table 2 shows the results of compar2isons across subjects. (Square root translormation was used in some cases :o obtain a linear regression.) In all cases the time constant ( SC,&) measure was that of the skin conductance response obtained dur@no, the rf--action tl-.ne series. Various measures of habituation rate were compared with this. Iii the first 2case it was the skin conductance response during the reaction time ser-les. This showed a 0.33 correlatioa with the rec6very time constant, (P <.G'-)which is interpreted as indicatin- that a short time constant is associated with sustained activation (motivation?) in the RT task. In another ccmparison, the habituation rate for SCR was obtained during the 1 tone series and compared with the same time coftstants as above. There was no si(,-nificant corzela@ion. Surprisingly the time constant obtained during the reaction time series.did correlate significan-ly %%rich clie rate of habituation of the fii-er pulse volume response HABITUATION N MEASURE r p 53 SCR during .33 <.05 Reaction Time 32 SCR during .13 N. S. Tones 51 FPV Change 3 .30 <.05 during Tones Table Correlation of recovery limb time const@-ncs obtained during reaction time with various babicu@-tioa measures taken across subjects. NMI -12- obtained e@uring the same toiic series c,.@,-LniLncd above (r O. 30, p < .05). Tilis relation of SCR recovery rate to an entirely different aucorioi-,iic measure in a different stiiiiulus situation is view2ed as an indication of the basic significance of this measure. 5. Relation of time constant length to quality of stimulus situation. To slied light upon the behavioral significance of chanr,,,e@:s in the time constant, its relation to a series of 8 graded stimulus situations @VaL$ examined. Although data on 21 slbjects are available, only 9 have b2een analyzed to date. The situations were: Relaxing - Eyes open - 2 minutes Relaxing - Eyes closed - 2 minutes Counti-ng aloud - 2 minutes ea ding alou d - 1. 5 m inutes Counting back-%vards by 7's - 2 minutes Deep breaths, 3 at 20 second L-itervals 2 Cold pressor test (ice bath) - 2 minutes Nlirror drawing - to completion Averao,e time constants were determined for each situation ar-d the 8 categories rank-ordered for each individual, tslng a rank of I for the longest. These ranks were then averaged for each condition. Results were in the f.:)Ilowing order: Situatio6n Averaize Rank Rest, eyes open 2.2 + 0.8 (Longest) Cold pressor 3. 1 +1. 2 Rest, eyes closed 3.3 1.2 Deep br atlis 4.2 - 1. 5 -13- Situation Average Rank- Count, forward 4.4 + 1.2 Count, back-%%,ard 5.6 + 1.9 Read aloud 6.1 + 1.3 i\@firror tracing2 6.6 + 1.3' @Shortest) Two features of this ranking are most significant, first that time constant becomes oal direction of the be ses. The second is Ut @io .!!10.@er apparently as the e that the cold pressor test though it produ2ced high activation shoved -%vaves Nvith time constants as long as those under resting conditions. This seems consistent with the above inference regardlno, the association of rap2Ld recovery limbs with goal directed beliavior. k is suggestive of a system in which mobilization for coal- directed activity.. involves activation of a rei-lex mechanism which hastens eledtro- 2 dermal recovery. Tests of stat-'-stical significance have not been made on this sample because of the additional analysis in progress. Nlevertheless, inspection of the means and deviatior.s makes it clear that the extreme categories are significantly different. 6. The biolo-ical basis for the variation in time constant was investigated on the basis of relations sug2gested in the last report. It had bee-,i hypothesized that the fast component cf the recovery limb might represent an epidermal men-Lbran@! process, associated Nvith the reabsorption phenomenon and with the positive skin potential response. Fccords from 11 subjects were examined, and L-%vo "pure" negative SPRs and odo with significant positive components were chosen fro3m each. The tirne constants Df the associated conduccance responses were measured and for i4- all 11 subjects, were shorter vilicn associated with positive SPRS (8.7 vs 14.9 seconds, P,@.001). A.,i example of a recor(Ung is seen in fic,,,ure 10. Since the reabsorption reflex had previously been slionvn to be associated with the positive wav2e, the association of short recovery tin-ies witit reabsorption was to. be e-,\pccted. Figure 11 shows an example (panel B) of the faster recoveries associated with the activation of rcal)sorption (Hydration increases up@vard). L\Iote the concomitant change in skin potential activity from negative to biphasic with a positive (doNin%'Vard) compon,'-4nt appearirg. The average time constant for the left h:ind panel was 7.4 seconds, for the ri6Ait, 4. S. A comparison on 12 subjects showed that reabsorption wa-ves were associated with steeper recovery limbs at the .01 --evel of significance. B. Peripheral Mechanism Because of the implicit involvement of the jceabsorption re2flex as a possible cause of the variation i,-i recovery linib slope, efforts were made to clarify -.ts mechanism. It had been previously postulated that this phenomenon represented a reflex increase in epidermal permeability. When this permeability increase occurred, the p3,ssive moverrent of water down its concentration gradient would appear as an innvard movement if surface 2vapor tension were tii@,h enou.-h. However, data on the low permeabilicy of the corneum cast doubt that the route was through this lailer (and then across the epidermis) - It was considered more lik-ely that the moisture was returning via the sweat duct. This possibility was invest,-gated by a modification of the inetsk-y prism method described by Thomas and Korr (1957) w5hich is s4@nsitive to frank- s@@,eat (droplets). In this modificalion, a photocell was substicuted for the Sp IlOk SC -Fo 16.7 6.6 Figure 10. Relation of recovery limb time constant to presence and absence of positive skin potential responses. 4 two ERAMM HYD 15 MV' SPR I5K B Figure 11. Relation of recovery limb time corL5tant to presence or4 absence of absorption refle@-. (upper trace, absorption is downward). Note acceleration of recovery limb with appearance of reabsorptiort responses. pliotorrrapliic cqtiiprticiit so that continuous recorcutigs of sweat -Jro let concentration p p could be made. Unlike the photographic metliod it is very important in this method that the light be wc'-l collimated to prevent contamination of th2e records with vascular changes (figure 12). It is also necessary that there be no possibility of variation in skin contact at the edge of the masked area. TesE of contamination by vasomotor activity were accomplished by inflation of venous and arterial cuffs on the arm to produce artificial vascular changes in the fingers. The system finally adopted was demonstrated to be free of such contamina2tion. The recordinos (figure 13) showed increases in sweat and also reab-sorption. Although the device has been used thus far on only 5 s-ubjects, all have manifested the phenomenon. It is now being used Ln conjunction with recordings of SPR, SCR, and hydration (elecerical method). The implications of the findings with this device is that the droplets of sweat fo2rmed at the sweat pore rather suddenly disappear. This has been confirmed by micro- scodic observation of the finger tip. This would indicate that t-ie cause of the reflex reduction of @@tion previouslv obs !rve moist.,.-,ied corneum but rather to drain-@ng of the sweat dror)lets back into the s,,-:eat duct. This may p2erhaps represent activity of the sweat duct wall at a relatively superficial level, e.g., at the germinating layer. Local Potential ResDorises The collectlon of data on the effects of variation in surface conditions upon LPR amplitude has been completed. As discussed in the summary, a relative ranae measure is a better indicant of effects than is an absolute comparison because of9 variation in direction of these effects. The data may be sumii-iarized as fo'-lows: Aghk Light Pilo Source Figure 12. Arrangement of light source and photoceu for observing changes in concencration of s%veat droplets by the prism technique. Increase in Sweat Reabsorption Figure 13. Rer-ords of sweat evolution and of reabsorption obtained by the photoeleceric prism technique. -16- Tllc control sites were subjected to a blank procedure Numbcfr of Subjects Witli iNT,,imber of Subjects With ENTeriiiicntat Site SIIOW- Control Site Showing ing Widest Range AfT2er A@lidest Range After Procedure Compcncnt Procedure Procedure o.5M Nla2SO4 Fast 5 I Slo-.v 6 0 5 iM I\Ta C L Fast 4 (I equal) I 2 Slow 5 I 0. 3t%4 A'C'3 Fast 3 6 Exsanguination Fast 6 0 Slcw 3 3 Temperature- Fast 5 I Slow 4 2 2 vicv upon LPR In addition, of 7 suhiects examined for effect of background ne,,-atiNe acti . amplitude, all showed a substantial increase for both fast and slow components (ave -ra ere 4 3070, P < . 00 1) . C. Bio-PsycholoZ,!@a7@@@ In the initia'L examination of adaptability or "-ear-shifting" cap--city, a pop- ulation of 60 subjects was run ttirough a battery consisting of ttle following, a) Several paper and pencil psychological evaluations including persoiality trait inventories, and manifest anxiety ratiners. -17- b) Pcrformancc tcsts: desif.-,iied to exaiiiine ri,-,idity- flexil)ility cliaracteristies. c) A knob-turnln- test designed to examine maintainance of appropriatq motor inhibition over an extended period. The su2bject was instructed to turn a large knob as slowly as possible tlirouf.;Ii 180 degrees. The time course of this effort was recorded and a comparison made of the angula-- velocity in the first third with that in the last third to detect I)reakdown of inhibition. This was expressed as a ratio K; a large ratio si,-nifies a speeding up in the last third (i.e., loss of inhibicion). Followin,y these tests the subject was fitted with electrodermal electrodes and a reflectance plethysmo,-raph. He was exposed in sequence to: a) 3 minutes of rest b) aseries of 5 tones, ca 80 db, 1000 cps c) aseries of 5 similar tones for reac2tion time test effort d) 3 minutes of rest e) adifficult discrimination task f) 5minl-tes of rest Although analysis is not yet completed, it appears that the psychological and performance tests, e:xcept for the knob-turning task showed low correlation with the physiological data. The relation of SCR recovery linib time constant to liabituatioa 0 rate in these runs has already been described. A relation between performance and physiological behavicr was also 'Lound. In these runs, as a measure of the "gear- shifting" abilit-y of the subject, his time for 50c' recovery from t:ne difficult cliscrii-nination task to base level during t[ic fijial rest period was decern-iined for skin con(iuctance, skin potential and finger pulse volume. The recovery half- tiliie for the clectrodermal level i-neaSL[rCS (not responses) was significantly related to K, the inliibitory ii-tde-,.. in the7 knob-curniiig task (P <. 05). Longer recovery times were associated with a tendency to speed up tocvard the end of tile tast-,. Put another way, the capacity to rnaint-lin inhibitory glotor control over an extended period was associated with an ability to sliift autonomic gears rapidly.