Comparing Risky Decision Making Under Conditions of Real and Hypothetical Consequences

In a series of three experiments, subjects made risky decisions under conditions of hypothetical or real consequences. Task variations across experiments included: (1) type of risk (monetary gambles or investments of time and effort), (2) within-subject and between-subjects manipulations of consequence condition, and (3) single or multiple decisions. The hypothesis of no difference between choices in real and hypothetical consequence conditions was retained in each experiment. Supplemental analyses ruled out various “artifactual” interpretations of the null results. Discussion focused on conditions in which researchers can and cannot infer decision makers’ actual risk preferences from their responses in laboratory tasks.     

Identifiability of a class of theories with states not directly observed over trials

The problem of identifying probabilities for sequences involving K underlying states is investigated for experiments in which there are K observed states, with the conditional distribution for these states specified for each underlying state. Conditions for finding unique estimates of the underlying probabilities are outlined for situations in which underlying transitions depend upon the last observed state as well as for situations in which no such dependency is assumed. No restrictions upon the nature of underlying transitions are assumed for a large number of trials. Applications to some known experimental situations are suggested.     

Detection of changes in spatial position: III. Dot number or dot density?

Better detection of changes in spatial position is achieved within random dot patterns consisting of a small number of dots rather than a large number of dots. Why? The result might be related directly to the number of display elements which must be monitored and thereby linked to the sharing of attention across display elements. The result, previously obtained for displays of constant area, might be related to the density of display elements and thereby linked to proximity relations within spatial patterns. Or the result may be due to the local separation of neighboring dots when inquiring about the state of a specific dot. The present study attempts to unconfound these factors. It is shown that performance is related to the number of dots that must be motored, irrespective of dot density; that dot density 18 effective primarily 10 the inquiry of the state of specific elements; and then principally as It relates to the separation of the queried element from its neighbors.