Introduction
A Time-Intensity (TI) method is a sensory evaluation technique used to assess the perceived intensity of a sensory attribute over a specific period, typically involving continuous measurements. Panelists are given a time-intensity question on a scale, and they are required to specify the intensity of a specified attribute as it changes over time. Time-Intensity methods are particularly valuable for studying dynamic sensory experiences, such as the release of flavors in food products, the development of mouthfeel properties, or the temporal aspects of various sensations. Continuous Time-Intensity (CTI) is a specific variation of this method where assessors provide continuous ratings throughout the entire evaluation, offering a more nuanced perspective on the sensory experience.
Template Description
The template starts with a welcome screen which can be used to provide additional information to panellists before the start of the TI task. In the design section, the first screen has instructions, followed by a question where participants can start the TI task.
Panellists are presented with one question where they are asked to click Start and indicate the intensity of the requested attribute over time.
Within the standard settings of the TI question type, you can choose to set up different options.
- Horizontal: Display the time intensity slider horizontally or vertically.
- Interval Time: Number of milliseconds between each measurement.
- Show Timer: Show the on-screen time for the panelists.
- Timer Countdown: Enable a countdown timer. Disabling this option will show a counter.
- Max number of intervals: Maximum number of measuring intervals.
- Auto drag: Disable mouse click, the value will be automatically selected when dragging the cursor.
- Resettable: Add a reset button after each measurement.
Within the advanced settings you can add more anchors on the scale while in the time settings, you can decide to display predefined messages to panellists at specified time. You have the flexibility to display a maximum of 10 messages.
In the end screen, the template incorporates a thank-you message, providing an opportunity for you to personalize a final message for the panellists.
In the design settings, you can check the way in which each panellist will receive the samples, with each set having a different presentation order for an individual panellist. In this template, three samples are presented in a monadic sequential order, implying that all questions in the design section will be asked for each sample consecutively.
If you wish to include additional samples, you can achieve this by navigating to Design > Generate Design and modifying the number of samples. Subsequently, click on Generate Design to implement the changes.
Raw Data Representation
The raw data will be displayed, with each row corresponding to a specific panelist and the respective sample they evaluated. The data includes an initial column containing all values stored as intensity, along with the associated time point. Subsequently, you will have the intensity scores given for each time point in each column.
Analysis
Once data has been gathered, you can access EyeOpenR and navigate to the Time Intensity analysis.
References
- Lawless, H. T., & Heymann, H. (1999).