Gradable adjectives denote a function that takes an object and returns a measure of the degree to which the object possesses some gradable property (Kennedy, 1999). Scales, ordered sets of degrees, have begun to be studied systematically in semantics (Kennedy, to appear, Kennedy & McNally, 2005, Rotstein & Winter, 2004. We report four experiments designed to investigate the processing of absolute adjectives with a maximum standard (e.g., clean) and their minimum standard antonyms (dirty). The central hypothesis is that the denotation of an absolute adjective introduces a 'standard value' on a scale as part of the normal comprehension of a sentence containing the adjective (the "Obligatory Scale" hypothesis). In line with the predictions of Kennedy and McNally (2005) and Rotstein and Winter (2004), maximum standard adjectives and minimum standard adjectives systematically differ from each other when they are combined with minimizing modifiers like slightly, as indicated by speeded acceptability judgments. An eye movement recording study shows that, as predicted by the Obligatory Scale hypothesis, the penalty due to combining slightly with a maximum standard adjective can be observed during the processing of the sentence; the penalty is not the result of some after-the-fact inferencing mechanism. Further, a type of 'quantificational variability effect' may be observed when a quantificational adverb (mostly) is combined with a minimum standard adjective in sentences like The dishes are mostly dirty, which may receive either a degree interpretation (e.g. 80% dirty) or a quantity interpretation (e.g., 80% of the dishes are dirty). The quantificational variability results provide suggestive support for the Obligatory Scale hypothesis by showing that the standard of a scalar adjective influences the preferred interpretation of other constituents in the sentence.Gradable adjectives like wet or straight or dirty have been analyzed as denoting a function (technically designated a function of semantic type ) that takes an object and returns a measure of the degree to which the object possesses some gradable property (e.g., the property of being clean; Kennedy, 1999, 2006, Kennedy & McNally, 2005. Most psycholinguistic research on adjectives (see brief review below) has focused on relative adjectives, like tall or expensive. The values on the scale of such adjectives depend heavily on the noun that they modify (an expensive wine is much cheaper than an expensive car). In contrast, we will focus here on absolute adjectives, and in particular, absolute gradable adjectives that have antonyms such as clean-dirty, healthy-sick and dead-alive. There is of course some context dependence in the interpretation of these adjectives too (we impose stricter standards of cleanliness on a clean plate than on a clean floor) but this has been argued to be a matter of 'precisification,' imposing stricter standards when precision is important, rather than of 'vagueness' (see Kennedy, to appear, for the distinction and examples o...