The Bayesian‐Laplacian brain

Abstract

We outline what we believe could be an improvement in future discussions of the brain acting as a Bayesian‐Laplacian system. We do so by distinguishing between two broad classes of priors on which the brain's inferential systems operate: in one category are biological priors (β priors) and in the other artefactual ones (α priors). We argue that β priors, of which colour categories and faces are good examples, are inherited or acquired very rapidly after birth, are highly or relatively resistant to change through experience, and are common to all humans. The consequence is that the probability of posteriors generated from β priors having universal assent and agreement is high. By contrast, α priors, of which man‐made objects are examples, are acquired post‐natally and modified at various stages throughout post‐natal life; they are much more accommodating of, and hospitable to, new experiences. Consequently, posteriors generated from them are less likely to find universal assent. Taken together, in addition to the more limited capacity of experiment and experience to alter the β priors compared with α priors, another cardinal distinction between the two is that the probability of posteriors generated from β priors having universal agreement is greater than that for α priors. The two categories are distinct at the extremes; there is, however, a middle range where they merge into one another to varying extents, resulting in posteriors that draw upon both categories.

The differential power of extraneous influences to modify aesthetic judgments of biological and artifactual stimuli

“…An interesting corollary to the supposition that there are inherited brain concepts through which aesthetic judgments are interfaced is the extent to which individuals can update such concepts, or beliefs, in light of new experience, as is generally assumed in Bayesian inferential models. Some of our previous results showed that experiences such as color, interfaced through biologically inherited concepts, are more resistant to updating than those interfaced through acquired concepts (Zeki, 2011;Zeki & Chén, 2020). We emphasize that, even in the updating of beliefs based on biological concepts in light of experience, there are gradations; color categorizations represent perhaps an extreme in not allowing any significant updating, as do stimuli that have certain "significant configurations" that mark them as constituting a human face (Zeki, 2013;Zeki, Javier, & Mylonas, 2020).…”

“…Kant (1790Kant ( /1987 supposed that aesthetic experiences, as opposed to "utilitarian" experiences, are interfaced through "indeterminate" concepts and, as a consequence, the experiencing individual could assume that his or her aesthetic judgment has universal assent. We, on the other hand, suppose that there should be some considerable agreement between individuals belonging to different ethnic and cultural groups in the aesthetic judgment of faces because they are interfaced through inherited brain concepts that are shared among all humans (Zeki, 2011;Zeki & Chén, 2020), which appears to be the case (see also Langlois et al,1991;2000). In line with our supposition, other studies indicate that assent on the perceived attractiveness of faces between individuals is substantially higher than assent for stimuli that fall under the artifactual category (Vessel et al, 2018;Zeki & Chén, 2020); in other words, an individual's aesthetic judgment of faces corresponds better to his or her imagined aesthetic judgment that other individuals might make of the same face compared to the judgments that other indviduals' might make of abstract artworks (Leder, Goller, Rigotti, & Forster, 2016).…”

“…In particular, we hypothesized that aesthetic judgments of images that belong to the biological categories, such as human faces, would be much more resistant to external opinion than aesthetic judgments of objects that may be considered to fall better under the category of artifactual, man‐made objects; we consider abstract, nonrepresentational paintings to fall into the latter category. This can be traced back to our general Bayesian–Laplacian classification of experiences into biological (β) and non‐biological or artifactual (α) priors (Zeki & Chén, 2020). At the root of this classification is our belief (Zeki, 2011), supported by recent empirical evidence (Vessel, Maurer, Denker, & Starr, 2018), that there is broader agreement between humans in general in judgments regarding biological categories than in those regarding artifactual categories.…”

The Neural Determinants of Beauty

“…Our next task is to determine how the brain handles aesthetic experiences derived from artifactual, man-made sources; we do not expect such experiences to be interfaced with inherited brain concepts, as in the experience of biological beauty. Rather, we expect that the experience of artifactual beauty is determined to a substantial degree by postnatally acquired concepts that are regularly updated in light of new experiences (Zeki 2009; Zeki & Chen, 2020). Whether such acquired concepts are also reflected in particular patterns in the relevant brain areas represents an important challenge for future studies in neuroesthetics.…”

“…This gives at least a partial answer to what neural mechanisms underlie the “subjective” side of the equation, leaving open the other side, namely of what objective characteristics of the apprehended objects lead to activity in the sensory areas of the brain and which result in the engagement of the mOFC as well; for only when a sensory stimulus is experienced as beautiful is the mOFC engaged along with the sensory areas. To address this question experimentally, we restricted ourselves to studying one category of beautiful stimuli, namely that falling into the biological category (Zeki & Chen, 2020) and, within that category, confined ourselves further to studying the neurobiology underlying the experience of facial beauty.…”