Performance

=Implicit memory of odors affects performance =  RESEARCH REVIEW by Ilona Lantos

 Reviewed: Joachim Degel and Egon Peter Köster: Odors: Implicit Memory and Performance Effects, Chemical Senses, 24: 317–325, 1999.

 The online version of this article was downloaded by Ilona Lantos on September 4, 2010 from:  []


 * Keywords**: lavender, jasmine, performance, creativity, mathematical, implicit memory


 * Abstract**: This study investigated the implicit influence of odors on human performance. 108 subjects completed a variety of tests involving creativity, concentration and mathematical calculations in 2 lightly scented rooms (jasmine, lavender) and in a third one, which was odorless. 30 minutes after they completed the tests, they were asked to match odors from a provided list of 12 odors (sandalwood, coffee, leather, lavender, jasmine, cedar wood, laundry, aftershave, ambient odors) and the presented 12 pictures of various environments including the testing rooms (train compartments, train lavatory, kitchen, bank, canteen, office, car). None of the subjects explicitly remembered smelling any odors in the testing environments. The odor of lavender enhanced test performance while jasmine or neutral odor decreased it.

Earlier studies showed that ambient odors (Gilbert et al., 1997) or suggested ambient odors (Knasko et al., 1990) did not influence performance. Other studies explicitly introduced odors during the learning phase (Schab et al., 1992). In another study (Torii et al., 1988) the stimulating and sedative effects of odors influenced the level of arousal but not performance. In the current study the subjects were not being told about the scents.The assumption was that subjects will be more productive, creative and make less errors under the stimulating odor condition than in the sedative or neutral odor conditions and that the fit between odors and visual contexts will be positively influenced by the implicitly learned odors in the test rooms.
 * Introduction:**

In this study 108 healthy individuals (54 males, 54 females) participated, average age 30. Participants were randomly divided equally into two experimental and one control groups.
 * 1. Subjects,** **size** **and method of selection**

The experiment took place in three different phases: performance testing, fit rating, pleasantness rating. The performance testing consisted of 3 types of tests: the creativity test (2 minutes), the concentration test (8 minutes), the mathematical test (8 minutes). The total duration of the tests was 45 minutes including 15 minutes of waiting and instruction time.
 * 2. Length**

First subjects took three types of performance tests in the 2 testing rooms with odors of lavender and jasmine and in one odorless room. Each subject performed the tests individually assigned to one of the 3 interviewers. The 3 interviewers alternated among the 3 groups. Neither the subjects nor the interviewers were told about the odors. In the creativity test (2 minutes) subjects had to name as many members of a given class of objects as they could think of. For instance, things that are red or things that make noise. In the concentration test (8 minutes) subjects had to count the frequency of a specified letter in 25 rows of 50 randomly arranged mirror letters (b, p, d, q). The mathematical test (8 minutes) consisted of 5 blocks, each including 15 tasks (5 addition, 5 subtraction, and 5 multiplication).
 * 3. Methodology**

30 minutes after they completed the tests, they were taken to another room to participate in a 30 minutes long hedonic properties of three types of cookies.

In the third phase subjects were taken another room and asked to rate the fit of odors between a provided 12 jars pf odorants (sandalwood, coffee, leather, lavender, jasmine, cedar wood, laundry, aftershave, ambient odors) and the presented pictures of various everyday surroundings including the testing rooms (train compartments, train lavatory, kitchen, bank, canteen, office, car). Three of them contained visual cues for leather or coffee. Pictures were presented randomly and the alternated between the ones that had visual cues or those that did not. Subjects had to rate the fit between all odors to each picture on a scale of 100 mm visual analog scale with the end labels "fit" and "does not fit". To prevent olfactory adaptation, subjects were asked to smell the inside of their arms after each rating, as well as a 45 second pause was held before showing a new visual context.

5 minutes after the ratings of fit test, subjects were asked to rate each odor for pleasantness, to write down the name of the odor and the place and time where and when they last time smelled the odor.

In the mathematical test, the jasmine group made significantly more errors than the other two groups. In the letter counting test the lavender group produced the least amount of errors. In the creativity test, interviewer A had a significant affect on performance.
 * 4. The results**

In the ratings of fit test, the jasmine test room received the highest fit to jasmine by the jasmine group compared to the lavender or control groups. The control test room got the highest control odor rating by the control group while there was no difference in ratings by the lavender and jasmine groups for the control room.

In the pleasantness rating, lavender was rated more pleasant than jasmine and coffee more pleasant than leather. The three groups did not differ in their ratings of pleasantness.

Lavender had positive effect on performance while jasmine had negative.

The authors of this study concluded that implicit perception of the odor of lavender significantly affect performance in the mathematical and letter counting tests. Subjects in the lavender room made the least number of errors compared to the jasmine or control groups.This might sound contradicting to what Torii et al. (1988) measured, namely that there is a correlation between alertness and performance, and jasmine is stimulating and increase performance while lavender is sedative and decrease performance. This contradiction can be explained by the Yerkes-Dodson law which says that there is an optimal arousal level for optimal performance. Below this level stimulating odor would raise performance and sedative odor would decrease it. Above the optimal arousal level these odors would have the opposite effect.
 * 5. The authors/researchers conclusions**

If odor source is visually present, odor and source easily connected.

The authors of this study also concluded that implicit memory for odors exists. When a person is exposed to some odor unknowingly he/she will connect that odor with that place later on. This implicit memory works especially for those who are unfamiliar with the odor and unable to specify the name of the odor. This was the case with the control group (they gave the highest score for the odorless sample fit to the control room) and the jasmine group (gave highest score for jasmine fit to the jasmine scented test room) and the non-identifiers in the lavender group. Those in the lavender group who were able to name the odor of lavender, did not rate lavender higher to the lavender test room than those in the control or jasmine groups.

The fact the non-identifiers have better implicit memory of odors contradicts with earlier findings according to which knowing the odor name has a better result in odor recognition tests (Lyman and McDaniel, 1986, 1990). Explanation is that those experiments introduce odors explicitly in the learning phase so the name and smell of the odor are stored in multiple memory pathways, in the semantic memory and the odor memory.

In the statistical analysis interviewer A produced the highest number of creativity test scores. Interviewer A also produced the best and the most stable results across the 3 different conditions. Is there an influence of a teacher on the outcome?
 * 6. Personal thoughts/analysis of the results**

Lavender enhanced performance implicitly. Lavender was rated more pleasant than jasmine. Were subjects above optimal level of learning states? In stressful situation (giving a speech), sedative oil might bring you to the desired mental state. What other sedative oils might be tested that are unpleasant to see if the positive affect is due to pleasantness or sedative properties? In a boring unrisky situation (listening to a presentation) stimulating oil might help.

Peripheral learning might explain the implicit memory of odor.

They measure too many things.


 * References:**

Gilbert, A. N., Knasko, S.C. and Sabini, J. (1997) Sex differences in task performance associated with attention to ambient odor. Arch. Environ. Health, 52, 195–199.

Knasko, S.C., Gilbert, A.N. and Sabini, J. (1990) Emotional state, physical well being, and performance in the presence of feigned ambient odor. J. Appl. Soc. Psychol., 20, 1345–1357.

Lyman, B.J. and McDaniel, M.A. (1986) Effects of encoding strategy on long-term memory for odors. Quart. J. Exp. Psychol., 38, 753–765.

Lyman, B.J. and McDaniel, M.A. (1990) Memory for odors and odor names: modalities of elaboration and imagery. J. Exp. Psychol.: Learn., Mem. Cogn., 16, 656–664.

Schab, F.R. and Crowder, R.G. (1995) Implicit measures of odor memory. In Crowder, R.G. and Schab, F.R. (eds), Memory for Odors. Erlbaum, New York, pp. 71–91.

Torii, S., Fukuda, H., Kanemoto, H., Miyanchi R., Hamauzu, Y. and Kawasaki M. (1988) Contingent negative variation and the psycho- logical effects of odour. In Van Toller, S. and Dodd, G.H. (eds), Perfumery. Chapman & Hall, London, pp. 107–120.

Yerkes, R.M. and Dodson, J.D. (1908) The relation of strength of stimulus to rapidity of habit formation. J. Comp. Neurol. Psychol., 18, 459–482.