Signals to the brain from the flows of energy around the body, varied primarily by declining amounts of food energy in the stomach, can explain the pattern of meals in the laboratory rat, the differences between dark and light phases, and the development of obesity ion the rat wioth VMH lesions but normal sating.

[Comment, pp 759-780] Lockhead (1992) [Target Article] is undoubtedly right to attack so-called intensity scaling or the estimation of subjective magnitudes as an invalid perversion of tasks requiring quantitative judgments of aspects of objects, stuffs, and situations. He goes too far, however, in claiming that feature scales do not exist... ... A perceived physical pattern (sensory feature or channel) and the cognitive process that integrates it with its context are characterized by determining to which particular combination of specified stimulus patterns (...) the response is most sensitive. This is the principle of causal system analysis that is at the basis of all theory-building science. (shrink)

Learnt incentive controls behaviour, not indiscriminate rewarded rreponding.

[Author's summary] Statement of empirical theory solely in words does not check if the theorising is effective in explaining observations, or even if it is self-consistent. It is important to complement words with a quantitative model that converts inputs to outputs through known mediating processes, although assumption and even the meanings of the model's terms remain open to challenge.

[Author's summmary, 2020]. Motivation specifically to drink (ingest watery materials) is widely assumed (still) to be innate, i.e. independent of exposure to fluids in contexts and sensory, somatic and/or social effects of their consumption. This comment floats the idea that human infants learn to differentiate textures of low-energy fluids from semi-solid and solid foods after they begin to be weaned from milk as sole drink and food.