Testing the assumptions of exponential,additive reaction time models

Two assumptions commonly made by choice reaction time (RT) models are (1) that certain experimental tasks can be found that cause an extra processing stage to be inserted into the cognitive process and (2) that the duration of one or more processing stages is random with an exponential distribution. Few rigorous tests of either assumption exist. This paper reviews existing tests and presents several new results that can be used to test these assumptions. First, in the case in which the duration of an inserted stage is exponentially distributed, it is shown that the observable RT density functions must always intersect at the mode of the density requiring the extra processing stage. Second, when only the first assumption (Assumption 1) is made, it is shown that the cumulative RT distribution functions and, in many cases, the hazard functions must be ordered. Finally, when only Assumption 2 is assumed, it is shown that, under fairly weak conditions, the taft of the RT density function must be exponential. The first two results are applied to data from a memory scanning experiment, and the two assumptions are found to receive tentative support     

Evidence for the self as an imaginal prototype

This study investigated recognition memory of self-photographs which had been previously rated by subjects for their degree of reference to an imaginal prototype of “real self.” The number of false alarms to NEW photographs was found to increase with degree of self-reference to the imaginal prototype with the exception of photographs rated highest in self-reference. Females were reliably superior to males in self-recognition. Males and females also differed in nonverbal behaviors reflecting differences in their image of real self. Results were interpreted as supporting an hypothesis that the self functions as a cognitive prototype which has both imaginal and verbal characteristics.     

An experimental psychology laboratory system for the Apple II microcomputer

A system for on-line control of experiments is described that uses the Apple II microcomputer and requires no knowledge of programming. This system, APT, is used to construct test files, randomize stimulus order, and conduct experiments. Construction of an experiment is very easy through use of an interactive program. APT provides powerful options for controlling stimulus duration, feedback, and response type. Programs are available to conduct either a sequence of tests without any experimenter present or a single experiment. Over 200 subjects, ranging from 18 to 86 years of age, have completed a battery of cognitive and abilities tests using the system.     

Constant errors donot occur in the matched reproduction of angles

MacRae and Loh (1981) reported that when observers attempt to match angles, whether simultaneously or successively, and regardless of whether the angles have the same orientation or not, acute angles generally are set too large and obtuse angles, too small. Without presenting data, they argued indirectly that starting-position effects in their adjustment procedure could not have accounted for the errors. In four experiments, we have demonstrated that effects similar to MacRae and Loh’s do occur when their starting positions are used and that no such effects occur when psychophysical methods that minimize or eradicate starting position effects are used.     

Arousal seeking as a moderator of life stress

This study investigated the relationship between life stress and measures of anxiety, depression, and hostility as a function of subjects' arousal-seeking status. Results indicated significant relationships between negative life change and measures of both anxiety and hostility. These relationships, however, held only for subjects who were low on the arousal-seeking dimension. The results suggest that arousal-seeking status may serve as a moderator variable in determining the relationship between life stress and other variables.     

Long-term retention of a visually cued poison-based aversion in monkeys.

Retention of a poison-based aversion after a 3-yr. period by 8 vervet monkeys (Cercopithecus aethiops) was found. The color of the visual cue appeared to effect the retention of the aversion.     

Manipulating the word frequency effect in free recall

A recall advantage for common words was not evidenced when subjects generated or rated the list words on the basis of commonness and on a semantic, phonological, or orthographic basis prior to recall. Recall of the same set of words following only structural judgments of the words resulted in the usual recall advantage for common words. Results were not consistent with interpretations based only on the associative strengths of the recalled items. A process based on categorization of the words to be recalled was suggested as an alternative explanation.