Three tests of intellectual performance capacity referring to factors V, S, and R, according to Thurstone's system of primary mental abilities were administered to a total number of 34 subjects. Immediately after finishing an individual item, subjects were asked to estimate the perceived difficulty of that item. The ratings were to be given on a…

A battery of 10 intelligence tests was administered to 22 subjects under standard conditions. After the testing session the degree of perceived similarity between 5 tests of the battery was to be estimated with regard to: (1) the kind of intellectual activity required by the tests, and (b) difficulty. Estimated qualitative similarity, according to…

Forty-three students participated in a laboratory experiment involving estimation of qualitative similarity between items sampled from ten conventional tests of intellectual performance. Estimated similarity could tentatively be described as a function of positive inter-test correlations as determined from another group of 123 individuals with the…

A simple device called a "wire labyrinth" was used in an experiment involving learning of a two-hand motor task. The Ss were asked, after completing each of 7 successive trails, to give their estimates of perceived (subjective) difficulty of the task. For this purpose, the psychophysical method of magnitude estimation was used. Time was…

Sixty subjects participated in an experiment involving estimation of difficulty of items in a test of reasoning ability. The estimates were to be given both according to conventional conditions of magnitude estimations with a preassigned comparison standard and according to a modified procedure of magnitude estimation where the comparison standard…

Nine studies are summarized which investigated the relation between attributes of performance as perceived by the subject and corresponding objective measurements. The attributes studied were: (1) intellectual activity perceived to be involved when dealing with a task (Studies 1 and 2), and (2) perceived difficulty (Studies 4 to 9). Study 3…