Beauty Requires Thought

Abstract

The experience of beauty is a pleasure, but common sense and philosophy suggest that feeling beauty differs from sensuous pleasures such as eating or sex. Immanuel Kant [1, 2] claimed that experiencing beauty requires thought but that sensuous pleasure can be enjoyed without thought and cannot be beautiful. These venerable hypotheses persist in models of aesthetic processing [3-7] but have never been tested. Here, participants continuously rated the pleasure felt from a nominally beautiful or non-beautiful stimulus and then judged whether they had experienced beauty. The stimuli, which engage various senses, included seeing images, tasting candy, and touching a teddy bear. The observer reported the feelings that the stimulus evoked. The time course of pleasure, across stimuli, is well-fit by a model with one free parameter: pleasure amplitude. Pleasure amplitude increases linearly with the feeling of beauty. To test Kant's claim of a need for thought, we reduce cognitive capacity by adding a "two-back" task to distract the observer's thoughts. The distraction greatly reduces the beauty and pleasure experienced from stimuli that otherwise produce strong pleasure and spares that of less-pleasant stimuli. We also find that strong pleasure is always beautiful, whether produced reliably by beautiful stimuli or just occasionally by sensuous stimuli. In sum, we confirm Kant's claim that only the pleasure associated with feeling beauty requires thought and disprove his claim that sensuous pleasures cannot be beautiful.

Keywords: Kant; aesthetics; beauty; emotiontracker; pleasure; psychophysics.

Figure 1.. Main results of Experiment 1.

(A) Examples of the six kinds of stimulus. (B) Time course of the pleasure rating (colored) and model fit (black) in Experiment 1 for each stimulus kind for trials without (blue and solid-black) and with (red and dashed-black) the added task requiring thought. The grey shaded area indicates the stimulus duration. A schematic of the model (Eq. 1) used to fit pleasure ratings is shown in the gap between beautiful images and the remaining stimuli. Colored lines with shaded areas represent mean ± 1 SE of the data. RMSE = root mean square error of the model fit across the entire 90 s trial duration; N = number of trials (and participants) per curve. Experiment 1 combines 1A and 1B, which each had 20 participants, for a total N = 40. (C) Mean estimated steady-state response r_steady for each kind of stimulus for trials without (blue) and with (red) an added task. Error bars represent mean ± SE. Across Experiments 1A and 1B, average r_steady estimates were 2.1 and 1.8 (on the 1 – 10 pleasure scale) lower in trials with an added task for self-selected beautiful and high-valence IAPS images, both p < 0.001, task × stimulus interaction F(4,152) = 7.99, p < 0.001. r_steady pleasure values for all other stimulus categories were unaffected, all p ≥ 0.407. There was no three-way interaction, F(4,152) = 1.86, p = 0.120. Interactions were tested with a 2 × 2 × 5 (task × experiment × stimulus kind) repeated measures ANOVA (rmANOVA) that excluded the teddy bear stimulus only presented in experiment 1B. A separate rmANOVA confirmed that there was no effect of added task on teddy bear trials, F(1,19) = 0.44, p = 0.513. Asterisks designate significant differences, without vs. with added task, according to post-hoc pairwise comparisons: *** p < 0.001. (D) Average final beauty judgment in Experiment 1 for each kind of stimulus for trials without (blue) and with (red) an added task. Error bars represent mean ± SE. Despite the three-way interaction of task, stimulus, and experiment, F(4,152) = 2.64, p = 0.031, separate repeated-measures ANOVAs per stimulus kind showed the same pattern of results as for pleasure r_steady: Average final beauty judgments were 0.5 and 0.6 (on our 0 – 3 scale) lower in trials with an added task for self-selected beautiful and high-valence IAPS images, both p < 0.001. Beauty judgments for all other stimulus categories were generally unaffected, all p ≥ 0.081. The only interaction of task and experiment was observed for candy, F(4,152) = 4.49, p = 0.041, all other p ≥ 0.098. For candy, the added task decreased beauty judgments in Experiment 1B by 0.6, p = 0.009, but the similar 0.5 reduction in Experiment 1A was not significant, p = 0.819. Asterisks designate significant differences according to post-hoc pairwise comparisons between trials with and without added task: ** p < 0.01, *** p < 0.001. (E) Receiver-operator-characteristic (ROC) curves [23] for classification of trials as with or without added task based on final beauty judgments (orange) and average pleasure during stimulus exposure (green) in Experiment 1. An area under the curve (A’) greater than 0.5 indicates better-than-chance decoding of task presence; asterisks (orange for beauty and green for pleasure) designate significant deviations of A’ from 0.5 based on bootstrap tests [24]: ** p < 0.01, *** p < 0.001. (F) Vertical histograms (binned scatter dot plots) of pleasure per stimulus kind for trials without task. The dashed lines indicate the estimated threshold pleasures P₁ and P₂ for perhaps and definitely feeling beauty, where P_i = median (P | i ≤ B ≤ i+1), calculated as the median, across stimulus kinds, of the median pleasure for trials with beauty rating in the range [1 2] for P₁ or [2 3] for P₂. Between the dashed lines, the green line indicates the threshold pleasure P_beau = 4.29 for effect of added task (see Figure 2). See also Figure S1–4 and Table S1–2.

Figure 2.. Relation between beauty and pleasure in Experiment 1.

(A) Effect of task on pleasure: average pleasure with vs. without added task. The all-pleasure attenuation model (not shown) for pleasure is P_task = g P_alone, where P_alone is pleasure without task, P_task is pleasure with task, and g is the task-dependent gain. Though not shown, it fits our data moderately well: 0.62 RMSE with 0.82 gain. However, looking at these data suggests that only high pleasure, exceeding some value P_beau (green tick mark), is attenuated. The black line indicates the prediction of this high-pleasure attenuation model. This is like retained income after a progressive tax, with a higher tax on income exceeding a certain level. It predicts P_task = P_alone if P_alone < P_beau, and P_task = P_beau + g (P_alone - P_beau) if P_alone ≥ P_beau. The high-pleasure attenuation model fit has 0.23 RMSE with a high-pleasure gain of 0.61 and a high-pleasure threshold P_beau = 4.29. The RMSE favors the high-pleasure attenuation model. Note that P_beau lies between the pleasure thresholds P₁ and P₂ estimated for perhaps and definitely feeling beauty (green between dashed lines in Figure 1F). (B) Difference between average pleasure without and with task. The black line represents the predictions of the high-pleasure attenuation model. (A-B) Ellipses indicate mean ± SE. (C) Predicted felt beauty B* vs. pleasure for every stimulus kind (color), without (hollow ellipses) and with (filled ellipses) the 2-back task. (D) Average beauty B versus felt beauty B*, for each stimulus kind (color) without (hollow ellipses) and with (filled ellipses) the 2-back task. The observed B response is quantized (0 … 3), but our model assumes that the internal feeling B* is continuous, with a fixed-variance normal distribution. In this plot, the value of felt beauty is a maximum likelihood estimate of the mean, based on the histogram of quantized beauty responses. The dashed line represents equality. The solid line represents the quantization function B = Q(B*) (see panel E). (E) Generative model for mean beauty and pleasure responses. Only gray nodes are observed. Round nodes are continuous; square nodes are categorical. Arrows indicate a causal relation. We presume that each kind of stimulus K has a (mean) stimulus effect s. We model the effect of added task by high-pleasure gain g. High-pleasure gain is set to 1 for the (baseline) condition without task. (The high-pleasure gain with task is a degree of freedom.) Felt pleasure and beauty are determined by nonlinear compression of the stimulus effect s by high-pleasure gain g, where P* = s if s ≤ P_beau, and P* = P_beau + g (s - P_beau) if s ≥ P_beau, and B* = a + bP*. The continuous feeling of beauty B* is quantized to produce the categorical response B to the beauty question at the end of the trial. The pleasure response P (measured as r_steady) is the felt pleasure P*.

Figure 3.. Main results of Experiment 2.

(A) Average steady–state pleasure r_steady and (B) final beauty judgments for each experiment without (blue) and with (red) an added task. The added task was 2-back (Expt 1, left, white bars) or digit-span (Expt 2, right, gray bars). Error bars represent mean ± 1 SE. Asterisks designate significant differences, with vs. without added task, according to post-hoc pairwise comparisons: *** p < 0.001. See also Figure S2.