Cognitive Enhancement Through Stimulation of the … Enhancement Through Stimulation of the Chemical...

Cognitive Enhancement Through Stimulation ofthe Chemical Senses

Phillip R. Zoladz and Bryan RaudenbushWheeling Jesuit University

Finding a non-pharmacological adjunct to enhance cognitive processingin humans would be beneficial to numerous individuals. Past research hasconsistently noted a significant interplay between odors and humanbehavior; for example, the administration of particular odorants enhancesathletic performance, mood, and sleep quality. In addition, odorants havea differential effect on human behavior, dependent upon route ofadministration (retronasal vs, orthonasal). The following study examinedthe differential effects of odoranis on cognition based upon route ofadministration. During Phase I, 31 participants completed cognitive taskson a computer-based program (Impact®) under five "chewing gum"conditions (no gum, flavorless gum, peppermint gum. cinnamon gum,and cherry gum). During Phase 11, 39 participants completed thecognitive tasks under four odorant conditions (no odor, peppermint odor,jasmine odor, and cinnamon odor). Results revealed a task-dependentrelationship between odors and the enhancement of cognitive processing.Specifically, cinnamon, administered retronasally and orthonasally,improved participants' scores on tasks related to attentional processes,virtual recognition memory, working memory, and visual-motor responsespeed. Implications are discussed in relation to providing a non-pharmacological adjunct to enhance cognition in the elderly, individualswith test-anxiety, and those with symptoms of dementia.

Finding a non-pharmacological adjunct to enhance cognitiveprocesses in humans would be both groundbreaking and readily acceptedby society. Attempting to enhance cognitive processing by such measurescould ultimately reduce a person's perceived cognitive effort for a task,while still allowing for an enhancement of his or her overall performanceon that task.

Since pleasant odors induce positive affective reactions, some haveargued that the mere presence of such odors may also lead to cognitive,social, psychological, physiological, and physical performanceenhancements, and evidence does exist to support this position. Forexample, Knasko (1992) found that a lemon odor led to fewer reports ofhealth symptoms, and Rottman (1989) noted that jasmine odor enhancedindividuals' performance on problem-solving tasks and led the

Author info: Correspondence should be sent to: Dr, Bryan Raudenbush, WheelingJesuit University, Dept. of Psychology, 315 Washington Ave., Wheeling, WV26003. E-mail at [email protected] American Journal ofPsychology,2005,Vo\. 1,"No. 1, 125-140.©NAJP

126 NORTH AMERICAN JOURNAL OF PSYCHOLOGY

participants to indicate higher levels of interest and motivation to thetask. Raudenbush, Koon, Meyer, and Flower (2002a) found thatpeppermint odor reduced ratings of pain over time and increasedparticipants' overall pain tolerance, as measured by a cold pressor test.Participants also reported reduced mental, physical, and temporalworkload requirements, lower effort and frustration, and increasedperformance and vigor in the presence of peppermint odor. Peppermintodor significantly increased oxygen saturation and blood pressure,providing evidence for its ability to physiologically arouse the humanbody. Raudenbush, Meyer, and Eppich (2002b) found that during atreadmill stress test peppermint odor reduced measures of workload,effort, fatigue, and frustration, while increasing self-evaluatedperformance and vigor. Raudenbush, Corley, and Eppich (2001) foundpeppermint odor increases running speed, handgrip strength, and thenumber of push-ups performed during a physical workout session.

Despite the numerotis reports that support the notion of odor-enhanced performance, however, some research has revealed theconverse. For instance, research has shown that the presence of apleasant lavender odor significantly undermines the performance ofworking memory, reaction time for memory and attention based tasks,and arithmetic reasoning (Ludvigson & Rottman, 1989; Moss, Cook,Wesnes, & Duckett, 2003). Thus, it would seem that it is not the merepresence of a pleasant odor that enhances performance, but rathersomething specific to the odorant itself.

Recent research has compared the effects of orthonasal and retronasalodorants on human behavior. According to Pierce and Halpem (1996),stimuli arrive at the olfactory epithelium through two distinct pathways:an orthonasal stimulus travels inward through the naris towards theolfactory mucosa, while a retronasal stimulus travels via the mouth to thenasopharynx. While Raudenbush, et al. (2002h) found that an orthonasaladministration of peppermint odor significantly enhanced athletic mood,performance, and workload, Zoladz, Raudenbush, Fronckoski, and Price(2003) did not replicate such fmdings when using a retronasaladministration of the same odor. Since research has shown that it is easierfor an odorant to affect human behavior if it is administered orthonasally(Puttanniah & Halpem, 2001), the effects odorants have on humanbehavior appears to be partially dependent upon the route by which theyare administered.

The following experiments were designed to assess tiie effects ofretronasal (Phase I) and orthonasal (Phase II) odorant administration oncognition. In Phase I, participants completed multiple cognitive tasksunder five retronasal odorant (via chewing gum) conditions (peppermintgtim, cirmamon gum, cheny gum, flavorless gum, and no gum). In Phase

Zoladz & Raudenbush COGNITIVE ENHANCEMENT THROUGH 127

n, participants completed multiple cognitive tasks under four orthonasalodorant conditions (peppermint odor, cinnamon odor, jasmine odor, andno odor). Participants also con:q)leted questionnaires assessing meastiresof mood and workload. It was hypothesized that orthonasal odorantadministration would have a greater impact on cognitive performance.Given the fmdings of past research, the administration of peppermintodor was expected to increase individuals' alertness and attention,ultimately enhancing their cognitive performance.

PHASE I: RETRONASALChewing flavored gum facilitates episodic and working memory in

humans (Wilkinson, Scholey, & Wesnes, 2002). Sesay, Tanaka, Ueno,Lecaroz, and De Beaufort (2000) report that mastication alone improvesregional cerebral blood flow, and Yagyu, Kinoshita, Hirota, Kondakor,Koenig, Kochi, and Lehmann (1998) suggest that the chewing offlavored vs, non-flavored gum activates different neuronal populations inthe brain. Most importantly, Morinushi, Masumoto, Kawasaki, andTakigawa (2000) showed that the specific flavor of gum, in addition tomastication, increases brain activity.

MethodParticipants. Participants were 31 young adult volunteers (13 males,

18 females, mean age = 20.19 years) obtained through conveniencesan^ling. Participants were students in a variety of psychology classesand were awarded course credit.

Stimuli. Gum stimuli consisted of peppermint (Wrigley's Extra*Peppermint), cinnamon (Wrigley's Big Red®), cherry (Fruit Stripe®), andflavorless gum (gum base).

Cognitive Performance Software. The Impact® software was used tomeasure a variety of aspects of participants' cognitive performance andfunctions (see Appendix A). Internal reliability for this instrument rangesfrom .88 to .94 in various san^les, with test-retest reliability of .80(Iverson, Lovell & Collins, 2002; Iverson, Lovell, Collins, & Norwig,2002).

Procedure. Participants were briefed as to the nature of the study,produced written consent, and provided demographic infonnation. Theythen began chewing a piece of gum (cinnamon, peppermint, cherry, orflavorless) for five minutes prior to the cognitive assessment, or, in thecontrol condition, sat quietly for five minutes instead of chewing gum.After five minutes had elapsed, participants completed the Impact® test,with those participants in the gum conditions continuing to chew the gimithroughout the duration of testing.


The protocol was completed five times in a repeated measures designwith each participant exposed to each condition, and with each conditionseparated by at least 24 hours. The order of the conditions was randomlyassigned, and each session lasted approximately 45 minutes. The Impacttest has five different versions of each sub-test, which limited practiceeffects.

ResultsCognitive Performance Scores. One-between (sex), two-within

(cognitive task, gum condition) ANOVAs were performed to comparecognitive scores for tasks on the Impact® test. One-within (gumcondition) ANOVAs were performed to compare composite scores ofverbal memory, visual memory, visual motor speed, reaction time, andimpulse control in the gum conditions. Alpha was set at .05, and TukeyHSD Post-hoc contrasts were performed to determine the direction ofeffects.

Design Memory Task. A trend was found for gum condition, Ftuf, =2.361, p = .OSl. Greater design memory scores were found in the

TABLE 1 Means and Standard Errors for the Cognitive PerformanceScores in Phase I

TaskWordDiscriminationDesignMemoryX's and O's

SymbolMatchingColor Match

Three Letters

Verbal Mem.CompositeVisual Mem.CompositeVisual MotorSpeed Comp.Reaction TimeCompositeImpulse Cont.Composite

No Gum45.89(.64)33.19(1.00)29.03(.33)9.16(-11)2.50(.03)24.93(.48)86.68(1-78)75.52(2.39)41.16(1.16)

,54(01)10.42(2.22)

Flavorless45,08(.87)34.52(.90)29.01(.40)9.15(.10)2,48(-04)25,40(.36)86.10(1.48)75,26(2.31)42.35(1-01)

.52(.01)12.00(2.83)

ConditionPeppermint

46,89(.50)33,25(.78)29.05(.43)9.13(-10)2.71(.16)25.7!(.29)87.87(1.57)76,94(2.14)41.62(1.00)

.54(-01)12.36(3,02)

Cinnamon45.99(.63)34.84(-95)28.98(.41)9.20(.10)2.65(,!6)25.91(34)89.61(1.45)76.26(2.44)41,96(.99).52

(,01)11.36(2,49)

Cherry45.37(.81)33.07(-98)29.94(.45)9.27(.09)2.72(,17)25.70(.37)88,94(1,42)75.19(2,29)41.57(1.28)

.53(-01)11.87(2.86)


cinnamon gum condition, as compared to the no gum condition and thechenry gum condition. There was a significant Gum x Task interactionfor design memory indicating that among the flavored gum conditions,cinnamon- and peppermint-flavored gum produced the greatest delayedmemory percent correct scores, F^o.sso = 2.034, p<.0\. There was nosignificant Gum x Sex interaction for scores on the design memory task,F4.,,6 = 2.033. p>.05.

FIGURE 1. Mean Overall Three Letter Memory Scores for the GumConditions in Phase I.

24No Gum Flavorless Peppermint Cinnamon Cheny

Gum

Three Letter Task. A trend was found for gum condition, /^j.ue =2,004, p = .099. Scores for the three letter task in the cinnamon gumcondition were greater than those scores in the no gum condition (seeFigure 1). There was also a significant Gum x Task interaction indicatingthat the three letter total percent correct scores in the flavored gumconditions were significantly greater tlian those scores in the flavorlessgum condition and the no gxim condition, FJO.SBC = 1.625, p<.05 (seeFigure 2), There was no significant Gtim x Sex interaction for scores onthe three letters task, /̂ 4,|,6 = ,566,/)>.O5.

No other significant effects were found for the cognitive performancescores in Phase I. Means and standard errors for all measures can befound in Table 1.

DiscussionThese results provide additional support that retronasal odorants can

enhance human behavior. While peppermint gum played a minor role in


the results of design memory scores, cinnamon gum had the mostconsistent directional influence on participants' cognitive performance.Data trends indicated that design memory scores in the cinnamon gumcondition were greater than design memory scores in the no gum andcherry gum conditions. Scores for the three letters task in the cinnamongum condition were also greater than those in the no gum condition,These results suggest that a retronasal administration of a cinnamonodorant has the potential to increase an individual's attentiona! processes,virtual recognition memory, working memory, and visual-motor responsespeed. Since the fmdings were not statistically significant, however, routeof administration may be playing a role in this effect.

FIGURE 2 Mean Three Letter Memory Total Percent Correct Scores forthe Gum Conditions in Phase I.

98,5

97.5

1 9 6 . 5

95,5

94.5

93.5

T

•

T1No Gum Flavwless Peppermint Cinnamon Cheny

Gum

The significant Gum x Task interaction for design memory suggestedthat among the flavored gum conditions, cinnamon- and peppermint-flavored gum produced the greatest delayed memory percent correctscores. Thus, the cinnamon- and peppermint-flavored gums allowed forparticipants to retain information in their memory for a longer period oftime. The significant Gum x Task interaction for the three letters tasksuggested that the total percent correct scores in the flavored gumconditions were significantly greater than those scores in the flavorlessgum and no gum conditions. This is of particular importance as itsuggests that flavored gum (in general) has the potential to enhanceworking memory and visual motor response speed.


Thus, the effects of retronasal odorants on human behavior are task-dependent; i.e., retronasal odorants enhance performance on particularcognitive tasks. Evidence that particular flavors of gum can enhanceworking memory links directly to research performed by Wilkinson, etal. (2002), where flavored gum (Wrigley's Extra* Spearmint) facilitatedepisodic memory and working memory. The present study finds the sameeffects, but for different flavors of gum.

PHASE n: ORTHONASALPrevious research has shown that an orthonasal peppermint fragrance

can significantly enhance athletic performance (Raudenbush, et al.,2002b; Raudenbush, et al., 2001), decrease perceived workload for agiven task (Raudenbush, et al.. 2002a, Raudenbush, et al., 2002b), inducephysiological arousal (Raudenbush, et al., 2002a), and enhance one'smood (Knasko, 1992). In Phase II, it was hypothesized that theadrtunistration of a peppermint fragrance would significantly enhanceparticipants' cognitive performance. Given the findings of Phase I, it wasalso hypothesized that the administration of a cinnamon fragrance wouldsignificantly enhance participants' cognitive performance, particularly onthe design memory and three letter tasks, which were enhanced by theadministration of this odorant in Phase I. It was expected that theseeffects would be more pronounced m Phase II, given an orthonasal routeof administration.

MethodParticipants. Participants were 39 young adult volunteers (3 males, 36

females, mean age = 18.38 years) obtained through conveniencesanpling, and were different from those participants in Phase I.Participants were students in a variety of psychology classes and receivedcourse credit for participation. Three participants were removed fromprimary data analyses to limit age variance [ages >30, (A/ = 45.33, SD =10.79)].

Stimuli. In each odorant condition, peppermint, cinnamon, or jasmineodor (Atdrich Co.) was added to low flow (1.3 Umin) oxygen via anAirsep Newlife oxygen concentrator, and delivered to the participantsthrough a nasal cannula bi-rhinally. In the control condition, only lowflow oxygen was administered. The jasmine condition was included as afurther con^arison, since its effects are quite the opposite of peppermintand cinnamon, i.e. relaxing rather than stimulating (Raudenbush, Koon,Smith, & Zoladz, 2003). No cherry odorant condition was used due tothe findings of Phase I, where cherry gum had no significant in5)act oncognitive performance.


Cognitive Performance Software. The Intact® sofhvare wasen^loyed, as per Phase I.

Additional Inventories. Profile of Mood States (POMS; McNair, Lon,& Droppleman, 1971), The POMS contains 65 mood adjectives to whichparticipants indicate the extent to which each describes them. Sub-scalesrelated to fatigue, anxiety, and alertness are calculated.

NASA-Task Load Index (NASA-TLX; Hart & Staveland, 1988). TheNASA-TLX measures workload along three dimensions (mental,physical, and ten^oral demand) related to demands imposed on theparticipant by the task, and three dimensions (effort, frustration, andperformance) related to the interaction of the participant and the task.

ProcedureParticipants were briefed as to the nature of the study (although not

about which odors would be used), produced written consent, provideddemographic information, and completed a pre-test POMS questionnaire.

TABLE 2 Means and Standard Errors for the Cognitive PerformanceScores in Phase II

TaskWordDiscriminationDesign Memory

X's and O's

Symbol Matching

Color Match

Three Letters

Verbal MemoryCompositeVisual MemoryCompositeVisual MotorSpeed Comp.Reaction TimeCompositeImpulse ControlComposite

No Odor44.61(.79)38.93(1,08)28.69(.21)9.18(.08)2.47(.04)25,55(.25)88.31(1.30)73.10(2.13)41.11(1.16)

.54(.01)9,08

(1.44)

ConditionPeppermint

44,39(.61)39.15(1.08)28,61(.24)9.25(.07)2.51(.03)25.59(.25)87.82(1,26)73.95(2.27)42,63(1,00)

.54(.01)9.59

(1,65)

Jasmine44.25(.60)40.19(1.03)28.73(.20)9.16(.09)2.50(.03)25,13(.36)87.00(1.44)76.87(1-89)41.57(1.09)

.53(•01)9,08

(1.22)

Cinnamon44.93(.59)40,68(1.04)28.74(.27)9.25(.09)2.48(.04)25,87(.26)89.44(1.27)75.90(2.04)41.52(1.22)

.53(01)9.90

(1.59)

Zotadz & Raudenbush COGNITIVE ENHANCEMENT THROUGH 133

After connection to the odorant delivery system, participantscompleted the Impact* test. Finally, participants completed a post-testPOMS questionnaire and completed the NASA-TLX workloadassessment.

The protocol was performed four times in a rejwated measures designwith each participant experiencing all conditions, and with each sessionbeing separated by at least 24 hours. The order of the conditions wasrandomly assigned, and each session lasted approximately 4S minutes.

ResultsCognitive Performance Scores.' Two-within (cognitive task, odor

condition) ANOVAs were performed to compare scores for the variouscognitive tasks among the odorant conditions. One-within (odorcondition) ANOVAs were performed to compare composite scoresamong the odorant conditions. Alpha was set at .05 for all analyses, andTukey HSD Post-hoc contrasts were perfonned to determine lhe directionof effects.

FIGURE 3 Mean Design Memory Delayed Memor>' Percent CorrectScores and Design Memory Total Percent Correct scores forthe Odorant Conditions in Phase II.

No Odor Peppermint Jasmine Cinnamon

• Delayed Memory Percent Correct • Total Percent Correct

Design Memory Task. There was no significant effect for odorcondition, fj.n* = 1,696. p>.05. However, there was a significant Odor xTask interaction, suggesting that delayed memory percent conect scoresand total percent correct scores were greatest in the cinnamon odorantcondition, F\t,6u "= I.710,;?<.05 (see Figure 3).


Three Letter Task. There was no significant effect for odor condition,^j.tn - 1.910,;? = .132. There was a significant Odor x Task interaction,suggesting that the percent of total letters conect scores were greatest inthe cinnamon condition. Fis.s7o = 2.461, /K.Ol. No other significanteffects were found for scores of cognitive performance in Phase II.Means and standard errors for all measures can be found in Table 2.

Workload Measures. One-within (odor condition) ANOVAs wereperformed to assess workload differences among the odorant conditions.No significant effects were found for any of these measures.

Mood Measures. Measures of mood were calculated before and aftereach condition by use of the POMS questionnaire. For each condition,the difference was taken between the pre- and post-recordings as anindication of the change in these variables during the experimentalsession. One-within (odor condition) ANOVAs were performed tocompare these changes.

Vigor. A significant effect was found for odor condition, Fj.m =3.058, /f<.05. Levels of vigor in the peppermint condition showed asignificantly smaller prc-post decline than the levels of vigor in the noodor and cinnamon conditions.

Fatigue. A significant effect was found for odor condition, Fj^w =2.922, p<.05. Levels of fatigue in the peppermint and jasmine conditionsshowed a significantly greater pre-post decline than the levels of fatiguein the cirmamon condition.

No other significant effects were found for die measures of mood inPhase II.

DiscussionThe results of Phase II support those of Phase I, suggesting that

cinnamon, administered retronasally and orthonasally, exhibits promisein enhancing cognition. Once again, however, the relationship betweenodorant administration and cognitive enhancement is task-dependent.The significant interaction for design memory suggests that delayedmemory percent correct scores and total percent correct scores weregreatest in the cinnamon odorant condition; this is consistent with theresults of Phase I, where the cinnamon-flavored gum significantlyenhanced design memory delayed memory percent correct scores.Additionally, the significant interaction for the three letters task indicatedthat the percent of total letter correct scores were greatest in thecinnamon odorant condition. Results of Phase I indicated that the threeletter total percent correct scores were greater in the fiavored gumconditions than in the no gum and flavorless gum conditions. The Phasen finding extended this interaction in Phase I, suggesting that thecinnamon odorant has a more pronounced effect (than other odorants) for


this task when administered orthonasally—route of administration doesplay a role in the amount of influence an odorant has on the enhancementof cognitive processing related to this task. This finding is con^arable tothat of Puttanniah, et al. (2001) who found that odorants have a greatereffect on human behavior if they are administered orthonasally.

Regarding the task-dependent relationship between odorants andcognitive enhancement, the fmdings in Phase II suggest that cinnamonodorant has the greatest potential to enhance attentional processes, virtualrecognition and working memory, and visual-motor response speed. Ofprimary importance is the fact that cinnamon had a more pronouncedinfluence on cognitive processing for the same scores on the same tasksin Phase II as it did in Phase I.

The significant odorant effects for pre-post changes in levels of vigorand fatigue support the notion that peppermint is an invigorating odorantthat prevents fatigue from affecting individuals during a task. However,since the peppermint odorant had no significant effect on the cognitiveperformance of individuals, these results provide no evidence for aninteraction between peppermint, mood, and cognition.

FIGURE 4 Mean Overall Three Letter Memory Scores for the OdorantConditions in Phase II: Data from Participants Excluded&om Original Data Analyses Due to Age.

16No Odor Peppermint Jasmine Cinnamon

SummaryPast research has consistently found that the administration of a

stimulating peppermint fragrance increases pain tolerance (Raudenbush,et al, 2002a), reduces workload (Raudenbush, et al., 2002a; Raudenbush,


et al., 2002b), enhances athletic performance (Raudenbush, et al., 2002b;Raudenbush, et al., 2001), and induces physiological arousal(Raudenbush, et al., 2002a). The present study suggests that anotherstimulating odorant—cinnamon—can enhance human cognitiveperformance. The fragrance, administered retronasally and orthonasally,can enhance one's attentional processes, virtual recognition memory,working memory, and visual-motor response speed.

The current findings have provide a foundation for ways to improvecognition, and additional groups of individuals should be studied, such asthose who are declining cognitively with age, suffering test anxiety, orsuffering from diseases that lead to dementia. Though the present studyconsiders non-clinical participants, its findings call for an assessment ofcinnamon's effects on the cognition of individuals with such afflictions.

Footnote'in order to examine the effects of age on an odorant's ability to

enhance cognition, participants originally excluded from the dataanalyses were included in two-within (cognitive task, odor condition)ANOVAs to compare their scores on the three letter task. One ANOVAcompared scores of all forty-two participants (i.e. older participants plusyounger participants), while the other ANOVA solely compared scoresofthe older participants. Three Letters - Older + Younger: There was asignificant effect for odor condition, F3_i23 = 3.700, g<.05. Scores on thethree letter task in the cinnamon and peppermint conditions weresignificantly greater than scores on the three letter task in the jasminecondition. Further, there was a significant Odor x Task interactionsuggesting that the total sequence correct scores, total letters correctscores, and percent of total letters correct scores were greatest in thecinnamon condition, Fjs,6[5 = 3.826, p<.00\. Three Letters - Older: Atrend was found for odor condition, fj.e = 3.726, p = .08. Post-hoccontrasts revealed that scores on the three letter task in the cinnamoncondition were greater than scores on the three letter task in the jasminecondition (see Figure 4). Additionally, there was a significant Odor xTask interaction suggesting that the total sequence correct scores, totalletters correct scores, and percent of total letters correct scores weregreatest in the cinnamon condition, f;j.3o = 6.226, p<.001. Thus,cinnamon, administered orthonasally, may be particularly salient in theenhancement of cognition in elderly individuals. Such a significantfmding provides a solid foundation for finding ways to improve memoryand other cognitive functions in individuals experiencing age-relateddementia. It also calls for research directed at enhancing theseindividuals' cognition via orthonasal odorant administration.


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APPENDIX AIir^act Software Program Assessments

Assessment #1 - Word Discrimination

This test assesses artentional processes and verbal recognitionmemory. Twelve words are presented on the computer screen,each for approximately 750 milliseconds. Subsequently,participants are presented with 24 different words, 12 of whichwere part ofthe list they just viewed, and 12 of which were notpart ofthe list they just viewed. Participants must decide whichwords were part of the list and which words were not part of thelist by supplying a "yes" or "no" response to each ofthe 24words presented.

Assessment #2 - Design Memory

This test assesses attentional processes and visual recognitionmemory. Twelve various designs are presented on the computerscreen, each for approximately 750 milliseconds. After alltwelve designs have been presented, participants are presentedwith 24 different designs, 12 of which were part ofthe list theyjust viewed, and 12 of which were not part ofthe list they justviewed. Participants must decide which designs were part ofthelist and which designs were not part ofthe list by supplying a"yes" or "no" response to each ofthe 24 designs presented.

Assessment #3 - X's and O's

This test assesses visual working memory and visual processingspeed. Individuals are presented with a random assortment ofX's and O's, 3 of which are highlighted in yellow. Participantsare required to remember the location of the 3 highlighted letters


and recall that information after performing a distractor task (i.e.a task that is presented between the primary exposure to theinformation and the cued recall of that information in an atten^tto challenge the working memory of participants). Afterviewing the highlighted letters for approximately 1.5 secondsand also performing the distractor task, participants are asked torecall the location ofthe 3 highlighted letters. Participantsrepeat this task for a total of 4 trials.

Assessment #4 - Symbol Matching

This test assesses visual processing speed, learning, andmemory. At the top of the computer screen, participants arepresented with a grid that matches 9 numbers to 9 commonsymbols (i.e. star, triangle, square, arrow, etc.). At the bottomof the screen, participants are presented with a random symbolto which he or she must tnatch with a number on the top ofthescreen. After 27 practice trials have been completed, thesymbols paired with the numbers on the top of the screendisappear. Subsequently, participants are again presented withrandom symbols at the bottom ofthe screen, and he or she mtistrecall to which number the specific symbol was paired. Thisassessment records a reaction time score and a memory score.

r Assessment #5 - Color Match

This test assesses reaction time and impulse control/responseinhibition. Before begitining the assessment, participants areasked to click a "RED," "BLUE," and "GREEN" button as it ispresented on the screen. This screening procedure helps assure

I that subsequent trials will not be affected by color blindness.Thereafter, words are presented in either the same color of ink

^ as the words read ("blue" in blue ink) or a different color of ink("blue" in red ink). Participants are asked to click on the wordonly if the word is printed in the same color of ink as the wordreads.

Assessment #6 - Three Letters

This test assesses working memory and visual-motor responsespeed. Before testing, participants are allotted time to practice adistractor task, consisting of 25 grid blocks (5x5 grid design)numbered 1-25 in random order. Participants must click on theblocks in reverse order, starting with block #25 and progressingthrough block #1, Once the test begins, participants are


presented with three consonant letters (e.g. WFL). Immediatelyafter these letters have been displayed, they are removed and theparticipant must complete the distractor task. He or she is onceagain asked to perform the numbered grid task described aboveas quickly as possible. Once 18 seconds have elapsed, the gnddisappears, and the participant is asked to recall the three lettersthat were displayed on the screen earher.

Cognitive Enhancement Through Stimulation of the … Enhancement Through Stimulation of the Chemical...

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