Attention

= The Influence of Essential Oils on Human Attention = RESEARCH REVIEW by Ilona Lantos

// Reviewed: Josef Ilmberger, Eva Heuberger , Claudia Mahrhofer , Heidrun Dessovic , Dietlinde Kowarik , and Gerhard Buchbauer, The Influence of Essential Oils on HumAttention. I: Alertness, Chemical Senses, Apr 2001; 26: 239 - 245. //

// The online version of this article was downloaded by ilona lantos on July 4, 2010 from: // // http://chemse.oxfordjournals.org/cgi/reprint/26/3/239.pdf //

Alertness: speed of information processing (sleep to wakefulness)


 * Keywords**: ylang ylang, peppermint, 1,8 cineole, menthol, jasmine, alertness, attention

In this study about 420 healthy human subjects participated, aged between 16 and 67 years.
 * 1. Subjects and method of selection**

Six experiments were conducted. In each experiment two experimental groups and one control group of 20 or 30 individuals participate. In the first and second experiments ylang-ylang and 1,8-cineole (eucalyptus) were used with two experimental groups and one control group of 20 subjects in each. In the third and fourth experiment 1,8-cineole (eucalyptus) and menthol (peppermint) were used with two experimental groups and one control group of 20 subjects in each. In the fifth and sixth experiment peppermint and jasmine absolute were used with two experimental groups and one control group of 30 subjects in each.
 * 2. Size**

After putting on a mask subjects were asked to fill out a questionnaire, then for about 25 minutes simple reaction and motor tasks were conducted.
 * 3. Length**

A-B design was used, that is two trials per session. In each trial the appropriate substance was applied on a surgical mask. This substance was water in both trials for the control group, and in the first trial for the experimental groups. Subjects were not told which substance was on the mask.
 * 4. Methodology**

In each trial after putting on the mask subjects were asked to fill out a questionnaire and rate the odor pleasantness (from “smells pleasant” to “smells unpleasant”), intensity (from “weak” to “strong”), effect (from “stimulating” to “tiring”) and degree of relaxation (from “I feel relaxed” to “I feel tense”). Then subjects had to perform a simple reaction time task. The stimuli, a red ellipse was presented randomly on the screen for about 220 times. Subjects had to release the go button and press another button as fast as they could when the red ellipse appeared. The time interval between the appearance of the ellipse and releasing the go button was recorded as reaction time, whereas the time interval between releasing the go button and pressing the second button was the motor time.

Reaction time was longer in second trials compared to first trials in all experimental and control groups, except for the cineole (100 ml) group. When compared the two cineole groups, the higher dosage cineole brought faster reaction time. However menthol and Peppermint did not produce difference in reaction.
 * 5. The results**

Motor time in the second trial decreased for the cineole (100 ml) group and for the control groups. Peppermint, jasmine and ylang-ylang marginally increased the motor time in the second trial. Though water was rated as unpleasant and non-relaxing in the second trial, it resulted faster MT but not RT.

All fragrances were rated as more pleasant, more intense, more stimulating and more relaxing in the second trial than water in the first trial, except ylang-ylang, which together with water was rated less pleasant and less relaxing in the second trial.

Odor intensity was more obvious across the experimental groups than water in the control groups in the second trial.
 * 6. The authors/researchers conclusions**

All odors were perceived as more pleasant in the second trial compared to water in the first trial, except ylang-ylang, which also resulted in longer reaction time.

Cineole got the highest rate for relaxing in the second trial and also led to faster reaction and motor time compared to all other groups.

Odors, except cineole (100) decreased alertness in all experiments acting as destraction.

Perception influenced outcome. Placebo effect can be best illustrated with the control groups inhaling water in both trials, The more stimulating was the water perceived in the second trial, the more the reaction and motor time decreased, that is alertness increased.

Besides individual perceptions there are other factors determining odor effects on behavior, such as individual differences, level of existing alertness, expectations of effects, and personality.

The Differences chart about subjective rating shows that cineole (100 ml) differs only in the rate of perceived relaxation compared to other odors, as well as water. Pleasant odor causes relaxation. Relaxed state can lead to increased alertness. Not the odor but the perception influenced outcome (e.g.: water perceived less pleasant and causing tension in the second trial in the control groups). Cineole received highest score as relaxing and caused faster RT and MT. Only cineole (100) caused faster RT. Both cineole (100) and water caused faster MT. Odor perceived as pleasant results in increased relaxation, which supports increased alertness. Contrary, odor perceived as unpleasant (Ylang ylang), causes tension, which slows RT.
 * 7. Your own thoughts/analysis of the results**

Knasko, S. C. (1992) Ambient odor’s effect on creativity, mood, and perceived health. Chemical Senses, 17, 27-35.
 * References:**

Ludvigson, H. W., Rottman, T. R. (1989) Effects of ambient odors of lavender and cloves on cognition, memory, affect and mood. Chemical Senses, 14, 525-536.