Distance shorter than city block but in ratings not how it appears, perceive ad more similar in psych space bc like ideas 2 circles are same size. Nk more similar to china than vs bc china has more salient features. Alignment model: feature comparisons are important tries to specify how and why features should count. Transformation model: assumes things are similar if one can be transformed into another, and similarity is a function of how many steps it takes to transform: e. g. water to steam = 1 step, very similar, similarity is flexible. Availability and representativeness: availability heuristic = way in which memory influences our thinking behaviour, ppl make judgements and decisions on basis of relevant memories they retrieve, on basis of evidence. Drm test: list of words to remember, see words around sleep but not actually sleep most convinced they had seen that word indicated explicitly seeing it, clearly memory error.