Let’s say a thought pops into your mind: “I could open the window right now”. Maybe you then immediately stand up and go open the window. Or maybe you don’t. (“Nah, I’ll keep it closed,” you might say to yourself.) I claim that there’s a final-common-pathway signal in your brain that cleaves those two possibilities: when this special signal is positive, then the current “thought” will stick around, and potentially lead to actions and/or direct-follow-up thoughts; and when this signal is negative, then the current “thought” will get thrown out, and your brain will go fishing (partly randomly) for a new thought to replace it. I call this final-common-pathway signal by the name “valence”. Thus, the “valence” of a “thought” is roughly the extent to which the thought feels demotivating / aversive (negative valence) versus motivating / appealing (positive valence).

I claim that valence plays an absolutely central role in the brain—I think it’s one of the most important ingredients in the brain’s Model-Based Reinforcement Learning system, which in turn is one of the most important algorithms in your brain.

Thus, unsurprisingly, I see valence as a shining light that illuminates many aspects of psychology and everyday mental life. This series explores that idea. Here’s the outline:

  • Post 1 (Introduction) will give some background on how I’m thinking about valence from the perspective of brain algorithms, including exactly what I’m talking about, and how it relates to the “wanting versus liking” dichotomy. (The thing I’m talking about is closer to “motivational valence” than “hedonic valence”, although neither term is great.)
  • Post 2 (Valence & Normativity) will talk about the intimate relationship between valence and the universe of desires, preferences, values, goals, etc.—i.e. the “normative” side of the “positive-versus-normative” dichotomy, or equivalently the “ought” side of Hume’s “is-versus-ought”. I’ll start with simple cases: for example, if the idea of doing a certain thing right now feels unappealing (negative valence), then we’re less likely to do it. Then I’ll move on to more interesting cases, including what it means to like or dislike a broad concept like “religion”, and ego-syntonic versus ego-dystonic desires, and a descriptive account of moral reasoning and value formation.
  • Post 3 (Valence & Beliefs) is the complement of Post 2, in that it covers the relationship between valence and the universe of beliefs, expectations, concepts, etc.—i.e. the “positive” side of the “positive-versus-normative” dichotomy, or equivalently the “is” side of “is-versus-ought”. The role of valence here is less foundational than it is on the normative side, but it’s still quite important. I’ll talk specifically about motivated reasoning, the halo effect (a.k.a. affect heuristic), and some related phenomena.
  • Post 4 (Valence & Social Status) argues that social status (by which I mean more specifically “prestige” not “dominance”) centers around valence—more specifically, the valence that Person X’s brain assigns to the thought of Person Y. It’s slightly more complicated than that, but only slightly. I’ll discuss how this hypothesis sheds light on various status-related phenomena, like imitating the mannerisms of people you admire, and I'll also discuss the implications for status-related innate drives.
  • Post 5 (‘Valence Disorders’ in Mental Health & Personality) notes that, given the central role of valence in brain algorithms, it follows that if something creates systematic impacts on valence, it should lead to a characteristic suite of major downstream effects on mental life. I’ll propose three specific hypotheses along these lines:
    • (A) If the valence of every thought is shifted negative, that leads to a suite of symptoms strongly overlapping with depression;
    • (B) If the valence of every thought is shifted positive, that leads to a suite of symptoms strongly overlapping with mania;
    • (C) If the valence of every thought is “extremized”—very positive or very negative, but rarely in between—that leads to a suite of symptoms similar to narcissistic personality disorder.
  • Appendix A (Hedonic tone / (dis)pleasure / (dis)liking) has some more details about the hedonic tone (i.e., the “liking” side of the “wanting-versus-liking” dichotomy, in contrast to valence which is more about “wanting”). This appendix thus elaborates on the very brief discussion in  §1.5.2. I suggest that “hedonic tone” is a different brain signal from “valence”, but centrally involved in the valence-calculation algorithm.
  • Valence and AI alignment deserves a post too, but actually I already wrote that one a while ago: see Plan for mediocre alignment of brain-like [model-based RL] AGI. Check it out if you’re interested. I won’t discuss AI further in this series, with some minor exceptions, including a section at the very end of the Post 5.

Thanks to Tsvi Benson-Tilsen, Seth Herd, Aysja Johnson, Justis Mills, Charlie Steiner, Adele Lopez, and Garrett Baker for critical comments on earlier drafts. Banner image by DALL-E 3.