Flashbulb memories

Flashbulb Memories are memories for the circumstances in which one first learned of a very surprising and consequential (or emotionally arousing) event. Hearing the news that President John Kennedy had been shot is the prototype case. Almost everyone can remember, with an almost perceptual clarity, where he was when he heard, what he was doing at the time, who told him, what was the immediate aftermath, how he felt about it, and also one or more totally idiosyncratic and often trivial concomitants. The present paper reports a questionnaire inquiry into the determinants of such memories by asking about other assassinations, highly newsworthy events, and personally significant events. It is shown that while the Kennedy assassination created an extraordinarily powerful and widely shared flashbulb memory, it is not the only event that has created such memories. The principal two determinants appear to be a high level of surprise, a high level of consequentiality, or perhaps emotional arousal (assessed by both rating scales and ethnic group membership). If these two variables do not attain sufficiently high levels, no flashbulb memory occurs. If they do attain high levels, they seem, most directly, to affect the frequency of rehearsal, covert and overt, which, in turn, affects the degree of elaboration in the narrative of the memory that can be elicited experimentally. Parallels are made explicit between the behavioral theory and a less elaborated, speculative neuro-physiological theory of which R. B. Livingston (1967) is the proponent Finally, an argument is made that a permanent memory for incidental concomitants of a surprising and consequential (in the sense of biologically significant) event would have high selection value and so could account for the evolution of an innate base for such a memory mechanism.     

Inferences,affects, and intentions in a model of paranoia

Models of psychopathologies can be construed as modifications to the normal purposive behavior of an organism. The particular elements of purposive behavior to be emphasized here are (1) deriving facts about the environment (inferences), (2) attending to the self's needs, desires, and interests (affects), and (3) choosing directions and goals to fulfill these interests (intentions). A series of processes in a model of paranoia which performs these tasks will be described. We also describe the modifications made by the paranoid processes to the normal processes. A computer simulation has been constructed to test the model.     

The superiority of the pair-comparisons method for scaling visual illusions

Twenty-one Ss scaled the Delboeuf illusion by the methods of pair comparisons, constant stimulus differences, reproduction, and pair reproduction. The method of pair comparisons was clearly superior on all indices of validity, reliability, and efficiency. Pair comparisons forces the S to discriminate between treatment levels and avoids motor responses. Es should consider using pair comparisons or related methods which share these advantages.     

Methylphenidate and stimulus control of avoidance behavior

The introduction of a warning signal that preceded a scheduled shock modified the temporal distribution of free-operant avoidance responses. With response-shock and shock-shock intervals held constant, response rates increased only slightly when the response-signal interval was reduced. The result is consistent with Sidman's (1955) findings under different conditions, but at variance with Ulrich, Holz, and Azrin's (1964) findings under similar conditions. Methylphenidate in graded doses increased response rates, modifying frequency distributions of interresponse times. Drug treatment may have disrupted a "temporal discrimination" formed within the signal-shock interval. More simply, methylphenidate influenced response rates by increasing short response latencies after signal onset; this effect was more prominent than the drug's tendency to increase the frequency of pre-signal responses. When signal-onset preceded shock by 2 sec, individual differences in performance were marked; methylphenidate suppressed responding in one rat as a function of increasing dose levels to a greater degree than in a second animal, but both subjects received more shocks than under control conditions.     

The influence of communality,factor strength,and loading size on the sampling characteristics of factor loadings

A Monte Carlo approach is employed in determining whether or not certain variables produce systematic effects on the sampling variability of individual factor loadings. A number of sample correlation matrices were generated from a specified population, factored, and transformed to a least-squares fit to the population values. Influences of factor strength, communality and loading size are discussed in relation to the statistics summarizing the results of the above procedures. Influences producing biased estimators of the population values are also discussed.This study was supported in part by NSF Grant GB 4230. Computing assistance was obtained from the Western Data Processing Center and Health Sciences Computing Facility, UCLA, sponsored by NIH Grant FR-3.     

College Freshman Performance: Summer Entrants vs. Fall Entrants

Entering college students and their advisors—high school and college personnel—frequently assert that the student will do better academically by entering college during the summer term rather than during the fall term with its many extracurricular activities. Comparing the academic performances over the first two quarters of 320 summer quarter entrants with 320 fall quarter entrants at the University of Tennessee yielded no significant differences for season entered. The ACT composite score for each student was held constant by using analysis of covariance. Significant differences for year entered—1962 or 1963—were apparently a function of the lack of reliability in grading practices. The academic performance of entering students did not benefit from summer quarter entrance.     

Adjusting fixed-ratio schedules in the squirrel monkey

On an adjusting schedule of reinforcement, a parameter of the schedule is varied as a function of some characteristic of the animal's performance. In Experiment I, the fixed-ratio response requirement was varied as a function of the time that elapsed before the animal started responding in each fixed-ratio (initial pause). When initial pauses were shorter than a specified duration, the response requirement was increased; when they were longer than the specified duration, the response requirement was decreased. Specified durations of 1, 2, 4, 8, and 15 min were studied. The average response requirement maintained by each monkey was directly related to the length of the specified duration of initial pause. In Experiment II, the fixed-ratio response requirement was constant, but reinforcement occurred only when the initial pause was longer than a specified duration. The average durations of initial pauses were directly related to the length of the specified duration and to the response requirement. Meprobamate consistently decreased the average durations of initial pauses.     

Stimulus functions in chained fixed-interval schedules

Pigeons were required to complete three successive fixed-interval components to obtain food. When the same exteroceptive stimulus was correlated with the three components, responding was positively accelerated between food deliveries. When different exteroceptive stimuli were correlated with each component in a fixed sequence, prolonged pauses developed in the first component; low response rates developed in the second component; and responding was positively accelerated in the second and third components. When different exteroceptive stimuli were correlated with each component in a variable sequence, responding was positively accelerated in each component. Because the response and reinforcement contingencies were the same in all three procedures, the differences in performances must be due to the changes in the sequence of stimuli.