3.1

Phase I Experiment

An experiment was conducted by the Dalian Multidimensional Education Center involving 25 individuals with autism to test their color discrimination ability. Different color systems were utilized, such as NCS[5], GRA[6], and HBS, which was adopted for this study. The experiment provided colors of various shades based on the HBS changes. Specifically, each color varied according to the following parameters: H=0, 25, 50, 100, 175, 225, 290, with B and S both ranging from 50% to 100%, resulting in a total of 70 colors (see Figure 1). The test color samples were presented to the participants in a gradient arrangement, asking them to choose their preferred color. All participants took part in the experiment and made their color selections in turns, with two rounds of selection conducted, ultimately yielding 50 sets of experimental data.

From Figure 2, it can be observed that the experimental data show the largest flow area between different saturations (S) and brightness levels (B) for yellow and green, with the longest colored bars in the middle of the area, indicating a preference for choosing yellow and green the most. The results demonstrate that the autism spectrum disorder group has lower sensitivity to saturation and brightness, only being able to recognize different hues, indicating lower color recognition ability. Additionally, it was found that the participants had a narrower field of view, preferring colors closest to their eyes, specifically yellow, green, and teal, which were positioned in the middle of the samples, compared to choosing their preferred colors. Furthermore, during the experiment, stereotypical behaviors such as imitation and following were observed among all participants in the same room, which interfered with the experimental data. Based on these two reasons, a second phase of the experiment was subsequently designed.

Fig. 2

Schematic diagram of the results of Phase I Experiment

3.2

Phase II Experiment

Combining the results of Phase I with Phase II, the latter phase selected seven solid colors from the choices of Phase I as test samples (see Figure 3), and presented these colors to the participants in a random order for selection. Similarly, this stage of the experiment once again involved the same 25 participants with autism from Phase I for two rounds of testing, totaling 50 instances. To eliminate the misleading effects of stereotypical behavior on the experiment, participants were processed randomly, ensuring that only one participant made a selection at any given time. The testing procedure provided samples of the seven solid colors, allowing participants to freely choose their preferred color and record it. As shown in Figure 4, yellow was the most chosen color, accounting for 29.63% of the selections, differing from Phase I where the number of people choosing green significantly decreased, proving that Phase II effectively eliminated the interference of visual field issues on the experiment.

Fig. 3

Color samples of Phase II Experiments

Fig. 4

Schematic diagram of the results of the selection of Phase II Experiment

4.1

Experimental procedures

Through the two phases of the experiment, solid colors were applied to a space composed of six faces, forming a completely enclosed shape. The size of the space was set to match the dimensions of a typical bedroom area in the homes of individuals with autism.It refers to specific dimensions reference in the schematic diagram (Figure 5). This round of experiments aimed to test the feasibility of the results from the first two experiments in a real-world setting, transforming flat color stimuli into spatial visual stimuli. For this round, 50 individuals with autism were selected to participate in the testing. The experimental procedure allowed these 50 participants to choose which of the seven solid color spaces they wished to enter, based on color samples placed next to the doors of each space (see Figure 6). The order of entry was determined by the participants themselves, but they were required to enter all seven spaces, with each participant making two rounds of choices, for a total of 100 instances. Furthermore, participants could refuse to enter a space, and observations were recorded on the length of time each participant stayed in different colored spaces.

Figure 5.

Space schematic

Figure 6.

Seven color space diagrams

4.2

Experimental data processing

In the processing of experimental data, the user behavior optimization model t=A(P+a) was referenced as a standard for data processing to check the reliability of the experimental data from this design. Due to a lower level of cooperation within the experimental group, with some instances of refusal to enter, if a participant did not enter a particular color space, the coefficient A in the model is 0 (A=0); if they entered, then coefficient A is 1 (A=1). The dwell time for each participant is recorded as Pn (n∈N, N={1,2,3,4,…24,25}), and the cumulative dwell time for participants entering each color space is ΣPn, with the expected dwell time in space P0 being 60 seconds (P0=60). The ratio of the cumulative dwell time for participants entering each color space to the total dwell time is calculated as ΣPn/25×P0 (n∈N, N={1,2,3,4,…49,50}), with the results of the completion rate shown in Figure 7. Visitation and non-visitation data are statistically analyzed, and the t value for each color is calculated according to formula [7], with the final t value being the average.

Fig 7.

Statistical chart of the results of one round of completion rate

Due to the uncontrollable factors in the emotional states of individuals with autism spectrum disorder compared to the general population, the final results were calculated using the average of this method to determine the extent of color impact on the autism spectrum disorder group. The average results, as shown in Figure 8, indicate that yellow had the highest value, whereas the shortest duration of stay was in the purple space, with an average value of only 0.001.

Figure 8.

Histogram of one-round averages

To ensure the accuracy of the experimental data, the 50 participants were allowed to make a second round of selections on another day. This process was identical to the first round of study, with each individual from the autism community sequentially choosing their preferred color. The time spent in each of the seven color spaces was also recorded. The completion rates Pn for the seven color spaces are shown in Figure 9, and the average t results are shown in Figure 10. Both charts indicate that the autism community prefers yellow, with more participants refusing to enter the purple room.

Figure 9.

Statistical chart of the results of the second round of completion rates

Figure 10.

Histogram of second-round averages

4.3

Experimental results

To minimize fluctuations within the data, the experimental data were controlled within the interval (0, 0.1). According to statistical results, aside from the noticeably higher average value for yellow, which may approach 0.9, the averages for other colors were generally within the lower range (0.00≤t≤0.033). Based on the average completion rates, yellow accumulated the highest number of hours across both rounds of testing, reaching 32% in the first round and 30% in the second round. Orange had the second-highest completion rate after yellow, with both rounds achieving 20%. The results for green were slightly lower than orange, at 12% in the first round and 16% in the second round. Red, blue, cyan, and purple did not exceed 20% in any round of testing.