JP7449662B2 - Cosmetics evaluation method and cosmetics evaluation device - Google Patents

Description

The present invention relates to a method for evaluating an object and an apparatus for evaluating an object.

Attempts have been made in various fields to objectively evaluate the feeling that a user feels when using a certain object (i.e., the feeling of use).

For example, Patent Document 1 describes a method for evaluating the feeling of use of stick-shaped cosmetics. In the method described in Patent Document 1, a stick-shaped cosmetic product is pressed against a flat surface and the torque generated when rotating is measured, and its time dependence is based on the value obtained by waveform analysis using a predetermined mathematical formula. to evaluate the usability of stick cosmetics. This method uses a predetermined mathematical formula to find a correlation between a value obtained by waveform analysis and a sensory evaluation value, and utilizes that correlation.

In this way, it is known that it is possible to evaluate the usability of an object by finding physical properties specific to the object that can be correlated with the sensory evaluation value, and using that correlation to estimate the sensory evaluation from the physical properties. It is being

However, when using the object, the user often consciously or unconsciously thinks about things other than the feeling of use. In particular, users often think about things related to the price of the object, such as whether it is worth using, whether it is worth purchasing, and how much they are willing to pay for the object. Such thinking can also affect the sensory evaluation of the feeling of use felt by the user. It is thought that there are relatively large individual differences in the strength of thinking about things other than the feeling of use. Therefore, in evaluating the usability, conventional evaluation methods based on the correlation between physical properties and sensory evaluation values may not be sufficient when detailed analysis is desired. Furthermore, in view of the user's thinking tendency as described above, the same can be said for evaluations other than the usability of the object, such as evaluation of the amount of willingness to pay for the object.

Japanese Patent Application Publication No. 2016-75619

In view of the above points, it is an object of one embodiment of the present invention to provide a method that can more appropriately evaluate the usability of a target.

In order to solve the above-mentioned problems, a cosmetic evaluation device according to one embodiment of the present invention provides a time period after the use of the cosmetic for the test subject to answer the amount of money they are willing to pay for the cosmetic and the feeling of using the cosmetic. , by informing the subject in advance of the use of the cosmetic to make the subject aware of the amount he or she is willing to pay for the cosmetic and the feel of the cosmetic while using the cosmetic. Changes in cerebral blood flow in one or more of the inferior frontal gyrus (IFG), middle frontal gyrus (MFG), and frontal pole are measured, and the feeling of use of the cosmetic is evaluated based on the change in the cerebral blood flow.

According to one embodiment of the present invention, a method is provided that can more appropriately evaluate the usability of a target.

1 is a schematic diagram of an apparatus for carrying out a method according to one embodiment of the invention; FIG. FIG. 3 is a diagram showing a state in which a probe unit of an optical topography apparatus is attached to a subject's head, viewed from the right side and the left side. FIG. 2 is a schematic diagram showing a state in which a probe unit of an optical topography apparatus is attached to a subject's head. FIG. 2 is a flow diagram illustrating a specific example of a method according to one aspect of the invention. 3 is a diagram showing a schedule for acquiring data from a subject in Example 1. FIG. FIG. 3 is a diagram showing the correspondence between channels of an optical topography device and parts of the brain. FIG. 3 is a diagram showing the results of Example 1. FIG. 2 is a diagram clarifying the results of Example 1. FIG. 6 is a diagram showing the results of Example 2. FIG. 3 is a diagram clarifying the results of Example 2. FIG. 6 shows the results of Example 2a. FIG. 7 is a diagram showing the relationship between the softness determination value for channel 18 and the amount of brain activity at the time of application. FIG. 7 is a diagram showing the relationship between the softness determination value for channel 18 and the amount of brain activity at the time of application.

Embodiments of the present invention will be described in detail below.

<How to evaluate usability>
One form of the present invention is to measure changes in brain activity of the subject while using the object as changes in cerebral blood flow while making the subject aware of the amount of money they are willing to pay for the object and the feeling of using the object. This is an object evaluation method that evaluates the usability of the object and/or the amount of willingness to pay for the object based on changes. According to this embodiment, it is possible to more appropriately evaluate the usability of the object and/or the amount of willingness to pay for the object.

The "object" to be evaluated in this embodiment is not particularly limited as long as it gives rise to a feeling of use. The "object" may be a tangible object or a service that the user receives. Specific examples where the "target" is an object include cosmetics, such as makeup cosmetics such as foundation, lipstick, cheek, eye shadow, eyebrow, eyeliner, and mascara, face wash, lotion, emulsion, cream, and beauty serum. Basic cosmetics such as Also included are personal care products (hygienic daily necessities), such as hand creams, body creams (body lotions), nail products, nail care products, oral care products such as body shampoos, soaps, and toothpastes, fragrances, and fragrances. In addition, the "object" may be a tool, such as makeup brushes (powder brush, cheek brush, mascara brush, etc.), cosmetic tools such as hair brushes, sponges, and puffs, personal care tools such as toothbrushes, cotton, etc. Paper daily necessities such as tissues and wet tissues, health and beauty instruments such as facial beauty instruments, pressure point pressing instruments, etc. may also be used. Furthermore, the "target" may be foods, drinks, luxury goods, etc. Furthermore, when the "target" is a service, specific examples include makeup, aesthetics, massage, acupressure, body care, hand care, foot care, nail care, and the like.

Further, in this embodiment, "while the subject is using the object" can be a period of time that is continuous over at least part of the time that the subject is using the object. That is, the measurement data of cerebral blood flow, which is the basis of the evaluation, may be data measured over a predetermined period of time from the time when the subject started using the object to the time when the test subject finished using the object, or may be data measured over a predetermined period of time from the time when the subject started using the object to the time when the subject finished using the object. The data may be measured over a period of time.

In addition, "use" of a subject refers to, for example, when the subject is an agent such as cosmetics that is applied to the body surface (sometimes referred to as a body surface liniment), the subject uses the subject on himself or herself. Refers to applying to the body surface of another person or applying the target to the subject's body surface. Furthermore, if the object is a cosmetic tool, it refers to actually applying cosmetics or the like with the cosmetic tool, and if the object is food, it refers to eating the food. Note that when the target is a service, for example, makeup, it refers to a makeup treatment being performed.

Preferably, the use of the object is in the manner in which the object is commonly used, or in the manner in which the subject normally uses the object. For example, since cosmetics are generally used while looking in a mirror, if the subject to be evaluated is cosmetics, the subject may be asked to apply the cosmetics while looking in the mirror. Furthermore, if the subject usually uses cosmetics in a private room, the subject may be allowed to apply the cosmetics in the private room during measurement. This makes it possible to obtain more accurate data on the mental and physical reactions (brain reactions) to the object, and to more appropriately evaluate the object.

The "feel of use" of an object is the feeling that occurs in the subject when the subject uses the object. This "feel of use" may be a sensation felt by one or more of a person's five senses. According to this embodiment, in particular, sensations including sensations felt by the subject through the sense of touch can be suitably evaluated. For example, when the ``target'' is a cosmetic, especially when it is a body surface application agent, ``feeling of use'' refers to the softness, smoothness, ease of spreading, ease of application, refreshing feel, moist feeling, and squeakiness of the target. Examples include lack of moisture, adhesion to the skin, stickiness, penetrating sensation, freshness, luster, and smoothness. This feeling of use is not a characteristic unique to the object, but a subjective sensation felt by a person.

The “willingness to pay amount” for an object is the amount that one is willing to pay for the object, that is, the amount of willingness to pay (WTP), also referred to as the maximum amount of willingness to pay. Whether or not an individual purchases an object is determined based on whether the price of the object exceeds or does not exceed the individual's willingness to pay. The amount of willingness to pay differs from a simple price evaluation; it is a value attached to an object in which the individual's actual desire to purchase is replaced by the price, and it also depends on the individual's own preferences, experience, economic situation, etc. The amount of willingness to pay can be said to be a standard for comprehensive financial evaluation of a target, and therefore, the amount of willingness to pay can be an important index in determining the direction of product development, setting product prices, etc.

<Outline of evaluation device>
FIG. 1 schematically shows an evaluation apparatus for implementing a method according to one embodiment of the present invention. FIG. 1 shows, as an example, an evaluation device 100 that uses functional near-infrared spectroscopy (fNIRS). The evaluation device 100 mainly includes an evaluation device main body 10 and a probe unit 12 connected to the evaluation device main body 10.

Functional near-infrared spectroscopy (fNIRS) irradiates near-infrared light from above the scalp through an optical fiber, passes through the scalp and skull, and converts the light reflected by the cerebrum back into electrical signals on the scalp. This is a method of detection. Since the intensity of reflected light in the cerebrum depends on the degree of light scattering by hemoglobin in the blood, changes in the concentration of hemoglobin can be determined from the detected electrical signals. On the other hand, it is known that when a certain part of the brain becomes active, the amount of blood flow, that is, the amount of hemoglobin, increases in that part. Therefore, by measuring changes in cerebral blood flow as changes in hemoglobin concentration using NIRS, the strength of brain activity (size of brain activation amount) can be measured.

Near-infrared light generally refers to light with a wavelength of about 600 to 1,800 nm, but because it easily passes through the living body, near-infrared light with a wavelength of about 600 to 950 nm is used to measure changes in cerebral blood flow using the method of this embodiment. It is preferable to use light of different wavelengths.

The probe unit 12 can be in the form of a cap that can be attached to the head of the subject SB as shown in FIG. 1, a head mount holder that can be placed on the forehead, or the like. The probe unit 12 is easy to attach and detach, and the subject can also move his or her body while measuring cerebral blood flow. Therefore, when measuring cerebral blood flow, it is possible to have the subject use the object in the same way as they normally do, so more accurate cerebral blood flow data can be obtained.

FIG. 2A shows a schematic diagram of the state in which the probe unit 12 is attached to the subject's head, viewed from the left and right sides of the head. In the probe unit 12, a plurality of detection probes 121 and irradiation probes 122 are arranged alternately, and a plurality of channels (measurement points) 125 are formed between the detection probes 121 and the irradiation probes 122. With this probe unit 12, changes in blood flow on the cerebral surface can be measured at a plurality of different locations. The detection probe 121 and the irradiation probe 122 of the probe unit 12 are each connected to the evaluation apparatus main body 10 via an optical fiber 13 (FIG. 1).

The electrical signal detected by the probe unit 12 (FIGS. 1 and 2A) is transmitted to the evaluation device main body 10 via the optical fiber 13. In the evaluation device main body 10, the electrical signal is converted into the above-mentioned hemoglobin concentration (more precisely, the product of concentration and optical path length). In the evaluation device main body 10, this change in hemoglobin concentration over time can be acquired as a change in cerebral blood flow. The concentration of hemoglobin is the concentration of oxygenated hemoglobin (also called Oxy-Hb) or the concentration of deoxygenated hemoglobin (also called Deoxy-Hb) (both units are mm x mm (concentration x Optical path length) or arbitrary units (au)) or both can be used. Among these, the concentration of oxygenated hemoglobin is highly sensitive to changes in blood flow that indicate the brain activation state, so the concentration of oxygenated hemoglobin (Oxy-Hb) should be used for measurement in the method of this embodiment. is preferred.

The evaluation device main body 10 may include analysis means for analyzing the electrical signal acquired from the probe unit 12, evaluation means for evaluating the object, storage means for storing analysis data and data of a database described below, and the like.

The evaluation device 100 may further include a display section 14, an instruction section 16, and an input section 18. These display section 14, instruction section 16, and input section 18 are all connected to the evaluation device main body 10.

The display unit 14 can display data on changes in cerebral blood flow obtained by converting electrical signals, and can display images formed based on the data (for example, optical topography images).

The instruction unit 16 is connected to the evaluation device main body 10, and issues instructions to start and end the use of the target, questions regarding the amount the target is willing to pay, questions regarding the usability of the target (described in detail later), and such questions. Instructions for answering the questions can be presented to the subject. The instruction unit 16 may be, for example, a screen installed in front of the tester as shown in FIG. 1, and can display instructions to the test subject in the form of images (including text) on this screen. The instruction unit 16 may be a speaker or the like that can issue audio instructions instead of images, or may be able to present instructions using both images and audio.

In the input section 18, the subject can input answers to questions, such as answers to questions regarding the amount of money they are willing to pay for the object and questions regarding the usability of the object. In addition, the subject can also input information other than the amount he or she is willing to pay and the feeling of use, such as the subject's free impressions about the object and the subject's personal information. The input unit 18 may be an input interface such as a touch panel, keyboard, or mouse. Alternatively, it may be a voice input device such as a microphone, a line of sight input device, or the like.

Units including the above-mentioned evaluation device body 10, probe unit 12, and display section 14 include the optical topography device "ETG series" manufactured by Hitachi, Ltd., and the brain function imaging device "LABNIRS" manufactured by Shimadzu Corporation. etc. can be used.

Note that the method for measuring changes in cerebral blood flow in this embodiment is not limited to functional near-infrared spectroscopy (fNIRS). Changes in cerebral blood flow can also be measured by, for example, functional magnetic resonance imaging (fMRI), positron emission tomography (PET), single photon emission tomography (SPECT), or the like. Furthermore, electroencephalogram (EEG) and magnetoencephalography (MEG) may be used. However, measurement by functional near-infrared spectroscopy (fNIRS) is preferable compared to measurements by other methods because the device is relatively compact and can be easily moved, so there are fewer restrictions on the measurement location. Furthermore, measurement by functional near-infrared spectroscopy (fNIRS) is less physically demanding on the subject, and therefore places less physical and/or mental burden on the subject. In addition, since there are few restrictions on the subject's body posture and movements, even if the use of the subject involves the subject's body movements, changes in cerebral blood flow while the subject is actually using the subject can be observed. can be measured. Therefore, data can be obtained in a more natural state that is closer to the actual situation, and the accuracy of evaluation can be improved.

<Measurement of changes in cerebral blood flow>
In this embodiment, a mental and physical reaction called cerebral blood flow is measured, and the measured value is used for evaluation. Therefore, it is possible to appropriately estimate and evaluate human sensations, which was difficult with conventional evaluation methods that measure only the physical properties of the object and evaluate the object based on the measured values. In addition, in sensory evaluations, etc., there is a time gap between when the subject uses the object and when he or she answers, so there is a possibility that the impression of the object changes and the evaluation value is revised. However, with the method according to this embodiment, it is possible to measure the physical and mental reactions (brain reactions) in real time when the subject is used, so it is possible to obtain faithful data based on the reactions, including the unconscious reactions of the subject. .

In addition, the measurement of changes in cerebral blood flow in the method of this embodiment is carried out while the subject is using the object, and at that time, the subject is asked to be conscious of or think about the amount he or she is willing to pay for the object and the feeling of using the object. Make it. In other words, the subject is made to pay attention to both the amount of money they are willing to pay for the object and the feeling of using the object.

When people use some kind of object in their actual daily life, they are thought to think about various things consciously or unconsciously while using the object. One of the main contents of such thoughts is considered to be the sensation felt by using the object. Another main consideration is considered to be the value of the object, such as the price and cost performance of the object, and whether or not the person wants to continue using the object or whether it is okay to purchase it.

Therefore, when measuring changes in cerebral blood flow in order to evaluate the feeling of using the object, even if the subject is made to pay attention only to the feeling of using the object, the subject will not be aware of the feeling of the object while using the object. It is thought that there is a tendency to consciously or unconsciously think about prices, especially the amount of money people are willing to pay. Furthermore, there are individual differences in such thinking tendencies. In other words, it is thought that there is variation among subjects in the strength of their thinking about the amount they are willing to pay, which is associated with their thinking about the feeling of use. Therefore, the desired correlation may not be sufficient for detailed analysis, or data from many subjects may be required to obtain the correlation. In contrast, according to this embodiment, changes in cerebral blood flow can be measured by making the subject aware of the subject's usability and the amount of money they are willing to pay for the subject, and keeping the subject's thinking state as similar as possible. Therefore, according to this embodiment, more objective data can be acquired, and the usability of the object can be appropriately evaluated.

Similarly, even if we ask subjects to pay attention only to the amount they are willing to pay when measuring changes in cerebral blood flow in order to evaluate their willingness to pay, they will not feel the sensation of use while using the object. It is thought that there is a tendency to think consciously or unconsciously. Furthermore, there are individual differences in such thinking tendencies. In other words, it is thought that there is variation among subjects in the strength of their thoughts about the feeling of use that accompany their thoughts about the amount they are willing to pay. Therefore, the desired correlation may not be sufficient for detailed analysis, or data from many subjects may be required to obtain the correlation. In contrast, according to the present embodiment, changes in cerebral blood flow can be measured while keeping the subject's thinking state as similar as possible by making the subject conscious of the subject's usability and the amount of money he/she is willing to pay for the subject. Therefore, according to this embodiment, more objective data can be obtained, and the amount willing to pay for the object can be appropriately evaluated.

In order to make a subject conscious of or think about the amount he or she is willing to pay for an object and the feeling of using the object, for example, the subject is provided with a task that makes the subject think about the amount he or she is willing to pay and the feeling of using the object. More specifically, before using the target, answer questions regarding the amount of money you are willing to pay for the target (sometimes referred to as the first question) and questions regarding the feeling of using the target (sometimes referred to as the second question). Make the subject aware of this in advance. After using the object, it is preferable to actually ask the first question and the second question to the subject and have them answer the subject. The first and second questions can be asked while using the target (while using the target), but the subject's attention may be drawn too much to reading the text of the question or to the text or text itself. It is preferable to ask questions after the subject has been used, as the brain's response to the subject may not be adequately measured while the subject is being used.

The first question is a question for determining the amount of money the user is willing to pay for the object, and can be, for example, a question such as "What is the maximum amount you are willing to pay for this object?" The answer to the first question may be a method of having the user answer an arbitrary amount or a method of having the user select from preset amount categories.

In addition, the second question is a question to judge the feeling of use of the object. If the feeling of use is "softness", for example, "Please rate the softness of this object". It's good to be there. As mentioned above, the feeling of use is the feeling that occurs to the subject when the subject uses the object, so we ask the subject to find out in advance the optimal feeling of use (referred to as the optimal feeling of use), and then select the object to be evaluated. Users can answer how far their usability is from the optimal usability. For example, it is possible to predetermine a scale range based on the optimal feeling of use, and have the user respond with the feeling of use within that range.

The above-mentioned first question and second question may be displayed simultaneously on the instruction section 16 for the user to answer, or may be displayed one after another and the user may answer the questions one after another. In the latter case, the order of the questions does not matter.

The cerebral region in which changes in blood flow are measured is preferably at least a part of the frontal lobe and the temporal lobe, more preferably at least a part of the anterior part of the frontal lobe and the temporal lobe, and even more preferably It may be at least one region of the superior frontal gyrus (SFG), in particular the right superior frontal gyrus, the middle frontal gyrus (MFG), the inferior frontal gyrus (IFG), and the temporal gyrus (TG). In the superior frontal gyrus (SFG) and middle frontal gyrus (MFG), the dorsolateral prefrontal cortex (DLPFC, Brodmann areas 9 and 46), particularly the right dorsolateral prefrontal cortex, is preferred. Changes in blood flow may be measured at one location, or changes in blood flow at multiple locations may be measured, and the data is analyzed as the area of the corresponding brain region, and in the evaluation, Usability and/or willingness to pay may be evaluated.

In particular, when evaluating the usability of a target, the cerebral regions where changes in blood flow are measured are the inferior frontal gyrus (IFG), especially the right inferior frontal gyrus, middle frontal gyrus (MFG), and superior frontal gyrus. The site may be in at least one of the gyrus (SFG) and the temporal gyrus (TG). In addition, when evaluating the amount of willingness to pay for a subject, the cerebral region where changes in blood flow are measured is the middle frontal gyrus, preferably the dorsolateral prefrontal cortex (DLPFC), and more preferably the right dorsolateral prefrontal cortex. It may be a body part. Therefore, by measuring the amount of brain activation in the middle frontal gyrus, preferably the dorsolateral prefrontal cortex (DLPFC), and more preferably the right dorsolateral prefrontal cortex as a change in cerebral blood flow, based on such measurement values, It becomes possible to evaluate both the user experience and the amount of money people are willing to pay for the product.

Note that each channel of the probe unit 12 (FIG. 2A) is mapped to a region of the cerebrum using the international 10-20 reference point as a medium, and the channels of the probe unit are mapped to the MNI (Montreal Neurological Institute) standard brain coordinate system. A probabilistic registration method (described in Singh, et.al, "Spatial registration of multichannel multi-subject fNIRS data to MNI space without MRI", NeuroImage 2005, 842-851, etc.) can be used to register the . Furthermore, projection by a known method such as a balloon inflation method or a convex hull method can also be used.

<Evaluation>
In this embodiment, the usability of the evaluation object and/or the willingness to pay (WTP) for the evaluation object can be evaluated based on the change in the cerebral blood flow measured. The evaluation can be performed using the evaluation device main body 10 shown in FIG.

In the evaluation device main body 10, as described above, the electrical signal acquired from the probe unit 12 is converted, and changes in cerebral blood flow can be measured and recorded as changes in hemoglobin concentration over time. In the evaluation, the measured hemoglobin concentration can be analyzed by a cerebral hemodynamic response function (HRF) using, for example, a general linear model (GLM). More specifically, parameters (β values, etc.) can be estimated based on a modeling function obtained by convolving a hemodynamic response function (HRF) with a rectangular function, etc., and this can be used to estimate brain activation. It can be used as an indicator of quantity. Note that the analysis model for changes in measured cerebral blood flow is not limited to the above.

The present inventors made the subjects aware of the feeling of using the object and the amount they were willing to pay for the object, and found that the difference between the amount of brain activation measured while the subject was using the object and the feeling of using the object as answered by the subject. We found that there was a significant correlation between the two. In addition, we made the subjects conscious of the feeling of using the object and the amount they were willing to pay for the object, and found that there was a significant difference between the amount of brain activation measured while the subject was using the object and the amount they were willing to pay for the object. We found that there is a correlation. Based on such a correlation, the usability of the object and/or the amount of willingness to pay for the object can be compared or estimated. As the brain activation amount, it is preferable to use the β value at the time of use of the subject.

When evaluating the usability, the usability of the object can be estimated using a database that has been constructed in advance. The database can be created by, for example, conducting an experiment similar to the above with multiple subjects using a predetermined target, and collecting data on brain activation amount (β value) and response data from the subjects regarding the feeling of using the target. , record the correlation between the two. The correlation may be determined by calculating a correlation coefficient from the collected data and recording it as the correlation coefficient.

Therefore, if you want to estimate the feeling of use that a subject or a group of subjects feels about a specific object, you can calculate the cerebral blood flow for the subject or a group of subjects under the same conditions as when the data recorded in advance in the database was acquired. By conducting a measurement experiment and comparing the results with the above database, it is possible to estimate the usability of the object.

Here, when calculating the correlation coefficient (for example, Spearman's correlation coefficient, etc.) between the amount of brain activation (β value) and the target usability, the correlation coefficient removes the influence of the willingness to pay (WTP). can be found. In that case, the correlation coefficient can be a partial correlation coefficient or a semi-partial correlation coefficient (partial correlation coefficient or one-partial correlation coefficient). Thereby, the correlation between the amount of brain activation and the feeling of use of the object can be determined more accurately.

Even if the usability of the target product improves by changing the conditions (target composition, sales method, etc.), the condition may have a direct impact on improving the usability evaluation, or the changed conditions may The influence may change another factor, and that other factor may have a large impact on the usability evaluation. Therefore, it is important to understand the influence of the other factors or to evaluate the usability excluding the influence of the other factors when analyzing the relationship between the conditions to be changed and the usability. Here, if the target is a product purchased by the user, the other factor mentioned above is often the user's impression or judgment regarding the price of the target. It is considered that the user's impression or judgment regarding such price can be appropriately expressed as the amount of willingness to pay. Therefore, by excluding the part influenced by the amount of willingness to pay from the brain response, and examining the correlation between the amount of brain activation and the feeling of use, it can be useful for product development and marketing.

In addition, as in the case of evaluating the usability, when evaluating the amount of willingness to pay, it is also possible to estimate the amount of willingness to pay for the target using a pre-built database. . For example, the database is created by conducting an experiment similar to the above with a predetermined target on multiple subjects, and collecting data on brain activation amount (β value) and response data of the subjects regarding the amount they are willing to pay for the target. and record the correlation between the two. The correlation may be determined by calculating a correlation coefficient from the collected data and recording it as the correlation coefficient.

Therefore, if you want to estimate the amount that a subject or a group of subjects is willing to pay for a specific object, you can estimate cerebral blood flow for the subject or a group of subjects under the same conditions as when the data was previously recorded in the database. By conducting a measurement experiment and comparing the results with the above database, it is possible to estimate the amount of money a person is willing to pay.

When calculating the correlation coefficient between the amount of brain activation (β value) and the amount of willingness to pay for the target, as in the case of evaluating the usability, we use a correlation coefficient that removes the influence of the usability, such as a biased A correlation coefficient or a semi-partial correlation coefficient (partial correlation coefficient) can be obtained. Thereby, the correlation between the amount of brain activation and the amount of willingness to pay for the object can be determined more accurately.

Even if the willingness to pay for a target improves by changing the conditions (target composition, sales method, etc.), the conditions may have a direct impact on improving the evaluation of the willingness to pay, or the changes may Another factor may be changed due to the influence of the conditions, and that other factor may have a large impact on the evaluation of usability. Therefore, it is important to understand the influence of that other factor or to evaluate the amount willing to pay excluding the influence of that other factor when analyzing the relationship between the terms to be changed and the amount willing to pay. Become. If the object is actually used by a user, another factor mentioned above is often the user's feeling of use of the object. Therefore, by excluding the part influenced by the feeling of use from the brain response, and examining the correlation between the amount of brain activation and the amount of willingness to pay, it can be useful for product development and marketing.

FIG. 3 shows a flowchart of evaluation of the amount of willingness to pay for the usability and symmetry of an object when a database is used as an example of the method according to the present embodiment.

Note that if both the usability and the amount of willingness to pay can be appropriately evaluated using this embodiment, both evaluations can be combined and used for product development, marketing, and the like.

(Experiment example)
Thirty female subjects between the ages of 25 and 35 were asked to actually use six types of lipsticks L1 to L6 of the same color (moderate red) but with different hardness, and changes in cerebral blood flow were measured during that time. did. The hardness of the L1 to L6 lipsticks was in the range of needle penetration hardness 5 to 134, as measured by a hardness meter (rheometer) (manufactured by Fudo Kogyo Co., Ltd.). Furthermore, the frequency of lipstick use by the test subjects was 5 or more times a week, and the test subjects were daily or almost daily lipstick users.

Cerebral blood flow was measured using an optical topography device (“ETG-4000” manufactured by Hitachi, Ltd.). First, a probe unit in which a detection probe and an irradiation probe were arranged alternately was attached to the subject's head (FIG. 1). In the above optical topography apparatus, a total of 33 detection probes and irradiation probes were arranged in 3 rows and 11 columns, and the number of channels (measurement points) arranged between the detection probe and the irradiation probe was 52 ( figure). The distance between the detection probes and the irradiation probes that are adjacent to each other in the vertical and horizontal directions was 3 cm. In the probe unit, the position of the sixth detection probe or irradiation probe (the detection probe or irradiation probe between channels 5 and 6) from the end of the bottom row almost coincides with Fpz, and the position of the detection probe or irradiation probe of the bottom row The channel was attached to the subject's head so that the line connecting T3-Fpz-T4, that is, the center in the vertical direction, approximately coincided with the horizontal reference curve H (FIG. 2A). Note that the above Fpz, T3, and T4 are positions on the head according to the international 10-20 method.

Then, according to the time schedule shown in FIG. 4, the subjects were asked to use one lipstick for each session. The lipsticks used in each experiment were randomly given to the subjects from lipsticks L1 to L6. In addition, instructions to the subjects were given through a display (Figure 1) placed in front of the subjects.

In this example, sessions as shown in FIG. 4 were measured for each subject. As shown in Figure 4, one block included a resting period, a withdrawal period, and two consecutive trials (first trial and second trial). In the resting phase, subjects sat quietly for 30 seconds, and in the removal phase, lipstick or stains were wiped off their lips using cotton impregnated with a cosmetic removal emulsion.

In the first trial, after handing a lipstick to the subject, instructions (instruction 1) about whether to apply the lipstick to the left or right side of the lips were displayed on the display, and the subject read the instructions and prepared to apply the lipstick. Once completed, it was started by pressing a key on the keyboard. A white blank screen was shown on the display, and a baseline measurement was performed for 12 seconds. Thereafter, the subject applied the lipstick to the instructed side of the left and right lips, and was instructed to finish applying the lipstick after 30 seconds. Then, when preparations were completed, the user pressed the enter key on the keyboard, and an instruction (instruction 2) to consider the "WTP" for the lipstick and the "softness" as the feel of the lipstick was displayed on the display. While the subjects were thinking about WTP, a white blank screen was shown on the display. After 5 seconds, the subject entered the value of "WTP" that he had considered using the keyboard, and also entered "softness" on a stepless scale, and pressed the enter key. Thus, in one trial, the subject applied one lipstick to one of the left and right sides of his lips and answered regarding the "WTP" and "softness" of the lipstick. In the second trial, a different lipstick was applied to the left and right sides of the lips that were not painted in the first trial, and "WTP" and "softness" were thought and input in the same way.

The screen or audio instructions in this example were given using E-Prime (registered trademark) from Psychology Software Tools.

Cerebral blood flow was measured for all six lipsticks L1 to L6 by performing three blocks each containing two trials as described above. Before the first session, subjects practiced one block without actually applying lipstick to get used to the measurements.

The subjects were asked to think of ``WTP'' as ``the amount of money they are willing to pay for that lipstick.'' In addition, when judging "softness," we used the "optimal softness" that felt just right, which was determined by the subject in advance, as the standard, and measured the degree of deviation from this "optimal softness." They were judged on a scale of 50 to +50.

Note that before the experiment (before starting the time schedule shown in FIG. 4), the experimental procedure was explained to the subjects and it was confirmed that they understood the explanation. Specifically, the subjects were asked about their "WTP" for the lipstick they were using and the "softness" of the lipstick they were using after applying the lipstick, and they were informed in advance that there would be time for the subjects to answer such questions. I informed them and they agreed. Thereby, while the subject is applying the lipstick, the subject can be made aware of the WTP for the lipstick and the "softness" of the lipstick.

In this example, cerebral blood flow was measured continuously from the start to the end of the session. In the measurement, changes in cerebral blood flow over time were obtained for each channel as a signal of oxygenated hemoglobin (Oxy-Hb) concentration (unit: mm×mm or au). The wavelengths of the near-infrared light used in this case were 695 nm and 830 nm, and the sampling rate was 10 Hz.

After measuring the change in cerebral blood flow, position measurement was performed using a 3D digitizer ("Patriot (trademark)" manufactured by POLHEMUS). Using the stochastic registration method from the data measured by the 3D digitizer, the data at the measurement points were projected onto the MNI (Montreal Neurological Institute) standard brain coordinate system. Based on the above projections, it was determined which part of the brain each channel corresponds to. Figure 5 shows the location of each channel identified on the brain surface.

The obtained time series data of Oxy-Hb concentration was analyzed by a cerebral hemodynamic response function (HRF) using a general linear model (GLM). MATLAB2007b (manufactured by Mathworks) was used for the analysis. The cerebral hemodynamic response function (HRF) is expressed as in equation (1).

In equation (1), τ _p is the first peak delay, which was set to 6 seconds in this example. τ _d is the second peak delay, which was taken to be 16 seconds. A is the amplitude ratio between the first peak and the second peak, and was set to 6.

The cerebral hemodynamic response function (HRF) h(τ _p , t) in the above equation (1) is convolved and integrated into the rectangular function N(τ _p , t) as shown in equation (2) to obtain the model function. f(τ _p , t) was created.

Using the obtained model function f(τ _p , t), a general linear model (GLM) analysis was performed. In the analysis, the model function f(τ _p , t), its first and second derivatives, and a constant term were used as regressors. Then, by regressing the Oxy-Hb concentration signal to the regressor, for each subject, for each channel, the time of application, the time of thinking about "WTP" and "softness", and the time of "WTP" and "softness" The β value at the time of input was calculated.

β values were calculated for lipsticks L1 to L6, respectively. Among the calculated β values, β _A1 to β _A6 are the β values at the time of application corresponding to the lipsticks L1 to L6, respectively, and W ₁ to W ₆ are the “WTP” input for the lipsticks L1 to L6, respectively. Based on the above, Spearman's rank correlation coefficient _rβW was calculated for each subject. Furthermore, based on the above β _A1 to β _A6 and the "softness" S ₁ to S ₆ selected and input for the lipsticks L1 to L6, r _Sβ and "WTP" W ₁ to W ₆ are similarly determined for each subject. r _SW was calculated for each subject based on the "softness" S ₁ to S ₆ .

(Example 1)
For each channel, based on the correlation coefficients _rβW , _{rSβ, and rSW} obtained for each subject, a semipartial correlation coefficient _rSβ|W was determined according to the following formula. This semi-partial correlation coefficient r _Sβ|W can be said to be a correlation coefficient between "softness" S and a component obtained by removing the influence of W (WTP) from β _A (brain activation amount at the time of application).

The obtained semipartial correlation coefficient r _Sβ|W was converted into a Z value using Fischer's Z transformation as shown in Equation (4). From the Z values determined for each subject, the arithmetic mean of the Z values of all subjects was determined for each channel, and a one-sample t-test against zero was performed.

The results are shown in FIG. 6, FIG. 7, and Table 1. FIG. 6 is a diagram showing the results of each channel of the above test displayed on a brain image. Further, FIG. 7 is a diagram illustrating channels shown in FIG. 6, excluding channels with particularly significant correlation. Table 1 also shows details of data for channels that had particularly significant correlations. Table 1 shows the average of the semipartial correlation coefficient _rSβ|W for all subjects, the average of Z value for all subjects, standard deviation, standard error, p value, and t value for each of the above channels. df (degree of freedom) is shown.

From FIGS. 6, 7, and Table 1, it can be seen that between the "softness" judgment value (S) and the component obtained by removing the influence of W (WTP) from the brain activation amount (β _A ) at the time of application, channel 4 , 7, 8, 11, 14, 18, 19, 21, and 39 were found to have significant within-person correlations.

From FIGS. 6 and 7, and with reference to FIG. 5 as appropriate, channels 4, 7, and 8 correspond to the inferior frontal gyrus (IFG), specifically the right inferior frontal gyrus, and channels 4, 14, 18, 19 corresponds to the middle frontal gyrus (MFG), channel 39 corresponds to the superior frontal gyrus (SFG), and channels 11 and 21 are channels (measurement points) corresponding to the temporal gyrus (TG). Channel 18 also specifically corresponds to the dorsolateral prefrontal cortex (DLPFC). From this, the amount of brain activation (β _A ) in at least a portion of at least one region of the inferior frontal gyrus, middle frontal gyrus, superior frontal gyrus, and temporal gyrus when the subject is applying lipstick is It was found that the correlation coefficient between the component excluding the influence of the WTP judgment value (W) and the "softness" judgment value (S) felt by the subject was significantly positive. Therefore, by using such a correlation and measuring changes in the subject's cerebral blood flow while using the object, it is possible to appropriately evaluate the feeling of use of the object, such as "softness".

(Example 2)
For each channel, based on the correlation coefficients _rβW , _{rSβ, and rSW} obtained for each subject, the semipartial correlation coefficient _rWβ|S was calculated according to equation (5), which is similar to equation (3) above. . This semi-partial correlation coefficient r _Wβ|S is the difference between the input value W of "WTP" and the component obtained by removing the influence of S (judgment value of "softness") from β _A (brain activation amount at the time of application). It can be said to be a correlation coefficient.

As in Example 1, the obtained semipartial correlation coefficient r _Wβ|S was converted into a Z value using equation (4). From the Z values determined for each subject, the arithmetic mean of the Z values of all subjects was determined for each channel, and a one-sample t-test against zero was performed.

The results are shown in FIG. 8, FIG. 9, and Table 1. FIG. 8 is a diagram showing the results of each channel of the above test displayed on a brain image. Further, FIG. 9 is a diagram illustrating the channels shown in FIG. 8, leaving out channels that had particularly significant correlations. Further, Table 2 shows details of data for channels that had particularly significant correlations. Table 2 shows the average of the semipartial correlation coefficient _rSβ|W for all subjects, the average of Z value for all subjects, standard deviation, standard error, p value, and t value for each of the above channels. df (degree of freedom) is shown.

From Figures 8, 9, and Table ₂ , it can be seen that the channel In 18 cases, a significant intra-individual correlation was found.

From FIGS. 8 and 9, and with reference to FIG. 5 as necessary, it can be seen that channel 18 is a channel (measurement point) corresponding to the middle frontal gyrus, particularly the right dorsolateral prefrontal cortex (RH-DLPFC). . From this, the amount of brain activation (β _A ) in the middle frontal gyrus, especially the right dorsolateral prefrontal cortex (RH-DLPFC) when the subject is applying lipstick, and the judgment value (S) of "softness" It was found that the correlation coefficient between the component excluding the influence of and the WTP value (W) was particularly significantly positive. Therefore, by using such a correlation and measuring changes in the subject's cerebral blood flow while using the object, WTP can be appropriately evaluated.

(Example 2a)
For each channel, the correlation coefficient _rβW obtained for each subject was converted into a Z value using equation (4). This correlation coefficient r _βW can be said to be a correlation coefficient when the influence of S (determination value of "softness") is not removed. From the Z values determined for each subject, the arithmetic mean of the Z values of all subjects was determined for each channel, and a one-sample t-test against zero was performed.

FIG. 10 shows a diagram in which the results of each channel are displayed on a brain image. Comparing the results of Example 2 (Fig. 8) above with the results of Example 2a (Fig. 10), in Example 2 (Fig. 8) excluding the influence of S (judgment value of "softness"), channel 18 It is clear that the correlation was particularly significant.

In addition, from Examples 1 and 2, in channel 18, there is a difference between the WTP value (W) and the brain activation amount (β _A ) at the time of application, and between the "softness" judgment value (S) felt by the subject and the time of application. It was found that a significant intra-individual correlation was obtained between both the brain activation amount (β _A ) and the amount of brain activation (β A ). Therefore, by using the brain activation amount data in channel 18, that is, by using the measurement data in the middle frontal gyrus, especially the right dorsolateral prefrontal cortex (RH-DLPFC), we can estimate the user experience of the target and the amount of money they are willing to pay for the target. Both evaluations can be performed. FIG. 11 is a graph showing the relationship between the judgment value S of "softness" in channel 18 and β _A for one subject, excluding the influence of the amount of willingness to pay. Further, FIG. 12 shows a graph of the relationship between WTP and β _A in channel 18 for the same subject who obtained the data in FIG. 11, excluding the influence of the "softness" determination value. Correlation is shown in both FIGS. 11 and 12.

10 Evaluation device main body 12 Probe unit 14 Display section 16 Instruction section 18 Input section 100 Evaluation device 121 Detection probe 122 Irradiation probe 125 Channel (measurement point)
H Horizontal reference line M Mirror SB Subject

Claims (11)

By informing the subject in advance, before using the cosmetic, that there will be time for the subject to answer questions regarding the amount of money they are willing to pay for the cosmetic and the feeling of using the cosmetic, before using the cosmetic. While making the subject aware of the amount of intention and the feeling of using the cosmetic, the subject's inferior frontal gyrus (IFG), middle frontal gyrus (MFG), and frontal pole when using the cosmetic. Measuring changes in cerebral blood flow,
A cosmetic evaluation device that evaluates the feeling of use of the cosmetic based on changes in the cerebral blood flow. By comparing the measured changes in cerebral blood flow with a database storing information regarding the correlation between changes in cerebral blood flow and the feeling of use of cosmetics,
The cosmetic evaluation device according to claim 1, which estimates the feeling of use of the cosmetic. 3. The cosmetic evaluation device according to claim 2, wherein the correlation between the change in cerebral blood flow and the feeling of use is a semi-partial correlation or a partial correlation that removes the influence of the willingness to pay. By informing the subject in advance, before using the cosmetic, that there will be time for the subject to answer questions about the amount they are willing to pay for the cosmetic and the feeling of using the cosmetic, before using the cosmetic. measuring changes in cerebral blood flow in the middle frontal gyrus (MFG) of the subject while using the cosmetic while making the subject aware of the amount they are willing to pay for and the feeling of using the cosmetic;
A cosmetic evaluation device that evaluates a willingness to pay for the cosmetic based on changes in the cerebral blood flow. By comparing the measured changes in cerebral blood flow with a database storing information regarding the correlation between changes in cerebral blood flow and the amount of money willing to pay for cosmetics,
The cosmetic evaluation device according to claim 4, which estimates a willingness to pay amount for the cosmetic. 6. The cosmetic evaluation device according to claim 5, wherein the correlation between the change in cerebral blood flow and the amount of willingness to pay is a semi-partial correlation or a partial correlation that removes the influence of the feeling of use. Any one of claims 1 to 6, wherein the test subject is made aware that, before using the cosmetic, he or she will answer a first question regarding the amount of money he/she is willing to pay for the cosmetic and a second question regarding the feeling of use of the cosmetic. Cosmetic evaluation device described in Section 1. The cosmetic evaluation device according to any one of claims 1 to 7, wherein the feeling of use includes a tactile sensation. 8. The cosmetic evaluation device according to claim 1, wherein the change in cerebral blood flow is measured using near-infrared spectroscopy (NIRS). The evaluation device is
By informing the subject in advance, before using the cosmetic, that there will be time for the subject to answer questions regarding the amount of money they are willing to pay for the cosmetic and the feeling of using the cosmetic, before using the cosmetic. While making the subject aware of the amount of intention and the feeling of using the cosmetic, the subject's inferior frontal gyrus (IFG), middle frontal gyrus (MFG), and frontal pole when using the cosmetic. Measuring changes in cerebral blood flow,
A method for evaluating cosmetics, comprising evaluating the feeling of use of the cosmetics based on changes in the cerebral blood flow. The evaluation device is
By informing the subject in advance, before using the cosmetic, that there will be time for the subject to answer questions about the amount they are willing to pay for the cosmetic and the feeling of using the cosmetic, before using the cosmetic. measuring changes in cerebral blood flow in the middle frontal gyrus (MFG) of the subject while using the cosmetic while making the subject aware of the amount he or she is willing to pay for and the feeling of using the cosmetic;
A method for evaluating cosmetics, comprising evaluating a willingness to pay for the cosmetics based on changes in the cerebral blood flow.

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