38 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS Having conceived an idea for a new or improved consumer benefit, the product development chemist is concerned to formulate it into an optimum product which can be passed to the marketing department. The object of this paper is to indicate the part that consumer studies can play in helping the product development chemist in research. TESTING INGREDIENTS Usually there are several possible compounds available which might be suitable for imparting the proposed consumer benefit. Some form of testing is required to screen out the most suitable ones. Although, if availa!,le, laboratory in vitro tests can help, often a check on live subjects is the most satisfactory test. Providing that there is sufficient information on the safety aspects, human subjects may be used to provide the substrate for application of the ingredient. The effects can be measured instrumentally or, in the absence of instruments, an expert judge or panel of expert judges may be used. Subjective opinions are not usually very valuable at this stage. Sometimes new compounds become available and it is necessary to find out what consumer benefits, if any, they offer. Again, if sufficient safety information is available they may be tested on human subjects as above. In order to keep the test as objective as possible when judges are used, it may be advisable to have only one aspect judged at a time. For example, if a new compound is applied to one half of a head of hair and the other half is left untreated as a control, one judge could be asked to assess the shine on the two halves. The judge should not know which is the treated side and which the untreated and this visual judgement should be made under standard lighting conditions. When a judgement of the feel of the hair is required, it may be better to ask another judge to assess this, under con- ditions where visual differences cannot be assessed. This would avoid any halo effect of a good gloss on one side causing judges to expect a difference in feel between the two sides. When only one judge assesses all aspects, analysis can show if one aspect is highly correlated with another but the correlation may either be a real one, i.e. the product could actually improve both gloss and feel of the hair, or it could be due to the judge associating the two aspects subconsciously. If several judges are used, unless the same aspects were subconsciously associated by all judges, this individual effect should be shown up. If only one judge is available, perhaps different heads should be used for judging each aspect. There will be head to head variation

THE ROLE OF CONSUMER STUDIES IN RESEARCH 39 but this occurs anyway and judgement on several heads would have to be made. It is best if the compound can be applied under strictly controlled conditions by a third party. Since judges must not know which side is which, they cannot apply the compound, unless two compounds which are both applied in the same way and look and behave similarly from the point of view of application are being compared on one head. Self application of materials not incorporated into a prototype product is best avoided. TESTING PROTOTYPE PRODUCTS Having found suitable ingredients, it is necessary to formulate them into satisfactory products, that is, products which allow the ingredient to have its effect and which are also acceptable in themselves. A shampoo, say, containing miracle ingredient X, must be an acceptable shampoo as well as giving X the opportunity to work its miracles. If it were possible to add the ingredient to a good, established product and be sure that the ingredient still exerted its effects without disrupting the properties of the product, it would only be necessary to find out whether consumers could detect the effects of the added ingredient and whether or not they liked it. Unfortunately some interaction usually occurs and a compromise is necessary to find the formulation showing the greatest effect of the ingredient combined with the least disturbance of the general product characteristics. Objective tests on human subjects are again useful in assessing possible products although, where subjects apply the product themselves, their subjective opinions on the method and ease of use may also be useful. Further information about the method and ease of use may be obtained by giving some panelists the product with any essential instructions for use and leaving them to use it instead of rigidly controlling the conditions. Discreet observation can indicate where improvements could usefully be made. Once the number of possible products has been narrowed down to a small number, say three or four, these products can be given to a suitable panel of consumers for their assessment. Great care is necessary with words when consumers' assessment is used. An ingredient or a product may be shown, in the laboratory, to have certain properties during use by a consumer it may be considered to have certain attributes and the two are not necessarily the same thing. For example, a