An explanation of conservatism in the bookbag-and-pokerchips situation

An experiment is described in which subjective probability revisions were obtained in a standard probability estimation task, the ‘bookbag-and-pokerchips’situation. Three aspects of probability revision were examined: conservatism, sequential effects, and coherence. Under two experimental conditions, the conservatism effect obtained was closely related to subjects' use of a simple strategy. A recency effect was also obtained. Coherence of the probability estimates was excellent. Conditions under which the observed strategy leads to conservatism are explored and previously published results are reconsidered in the light of this strategy. Conservatism in the bookbag- and-pokerchips situation is explained as an artefact of subjects' strategies     

INTERMITTENT REGRESSIONS IN A SERIAL AFTERIMAGE EXPERIMENT AS SIGNS OF SCHIZOPHRENIA

S mith G. J. W., R uuth E., F ranzén G. & S jöholm L. Intermittent regressions in a serial afterimage experiment as signs of schizophrenia. Scand. J. Psychol ., 1972 , 13 , 27 33.—A group of 35 young patients suspected of schizophrenia were tested in a serial afterimage (AI) experiment and were also rated on the Rockland-Pollin scale. Subjects with high psychotic scores showed one or more regressions to immature (size-constant, positive, physiognomic) images in their Al serials, images typical of children who cannot clearly distinguish their Ails as subjective phenomena distinct from the outside world. The Al test thus indicates schizophrenics to be characterized by intermittent withdrawal into a world of experiencing the self and non-self as not clearly distinguished. Regressions were rare in two control groups.