Statistical explanation in physics: The Copenhagen interpretation

The statistical aspects of quantum explanation are intrinsic to quantum physics; individual quantum events are created in the interactions associated with observation and are not describable by predictive theory. The superposition principle shows the essential difference between quantum and non-quantum physics, and the principle is exemplified in the classic single-photon two-slit interference experiment. Recently Mandel and Pfleegor have done an experiment somewhat similar to the optical single-photon experiment but with two independently operated lasers; interference is obtained even with beam intensity so small that only one photon is in the apparatus at a time. The result can be understood in terms of the superposition of states; or, in terms of the Uncertainty Principle, which is found to forbid the determination of which of the two lasers is the source of a given photon (if conditions for interference are to obtain). The Mandel-Pfleegor experiment gives a physical argument against the continuous localization of a photon that is assumed in the hidden variable theories and therefore gives further support for the generally accepted view that an observed entity (observed state) is created in the observation event. This aspect of quantum physics implies a subjectivism on the level of individual quantum-level occurrences, since there is in quantum theory no basis for asserting the existence of the event independently of observation of it. Extension of this subjectivism to large scale, non-quantum phenomena falls within the principles of quantum theory; counter considerations that argue against such an extension are noted.     

Sex and coding strategy effects on reaction time to hemispheric probes

Two experiments were conducted to investigate the influence of coding instructions on cerebral laterality differences. Experiment I required 20 subjects (10 female) to use either rehearsal or imagery coding strategies in a recognition task with word probes to the right and left hemispheres. No hemispheric differences were found, but sex of subject was found to be related to coding strategy. Ten subjects (5 female) in Experiment II performed a similar task, except picture probes were used. Subjects using rehearsal coding responded faster to left-hemisphere probes, but faster to right-hemisphere probes when imagery coding was employed. The differing laterality effects in these experiments were attributed to naming responses implicitly required in Experiment II.     

Sequential search processes in long-term memory

In an experiment employing the symbol-element recognition task (Mohs, Wescourt, & Atkinson, 1975), subjects first learned six lists consisting of four words (elements) each. Each list was associated with a unique consonant (symbol). Subsequently, on each of a series of test trials, subjects were presented with one, two, or four symbol-element pairs. A positive response was required if all test words were correctly paired with their associated consonants and a negative response if any one test word was incorrectly paired with a consonant. Of primary concern was the way reaction time (RT) varied with number of pairs presented, the type of response required, and, on negative trials, the position of the mismatched pair in the test display. RT increased with the number of pairs presented on a trial and the increase was greater for positive than for negative trials. For negative pair trials, RT increased with the distance of the mismatched pair from the top of the test display. On negative trials in which the top pair in the test display was the mismatched pair, RT increased with the total number of pairs presented on the trial. A serial, probabilistic order of processing model is proposed to account for these results, and applications of the model to other paradigms are discussed.     

Classical aversive conditioning of heart rate in curarized rats at different blood gas levels

In an effort to examine whether normal blood gas tensions were essential for conditioning, paralyzed rats received a classical aversive heart rate (HR) conditioning session while respirated at different peak expired CO₃ values. After the session, arterial blood was drawn for analysis. That peak expired CO₂ was effective in manipulating Pco₂ was indicated by a significant correlation (r = 0.594, df = 17, P < 0.05). In addition, only rats with blood gas values similar to those of anesthetized controls displayed a discriminated HR CR. These animals also had lower baseline HRs and greater HR variability. Further, 7 of the 9 rats with normal blood gas values were respirated at peak expired CO₂ values from 5.0–5.1 per cent, and no animal ventilated within this range displayed abnormal values. These findings suggest that previous difficulties in obtaining classical and operant conditioning in paralyzed animals may, in part, be attributable to inadequate ventilation.     

Digital computer estimation of eye fixations

A method is presented for estimating eye fixations to the degree of accuracy desired. In the process, the quantity of data is greatly reduced so that analysis can be accomplished at the end of each experimental run. The algorithm is particularly suitable for “slow” computers because the analog-to-digital conversion rate can be low and because the data reduction process decreases the number of calculations required to obtain the analytical results.     

Texture gradient effectiveness in the perception of surface slant

To assess the development of monocular slant perception as well as the relative effectiveness of different sources of information, children in first, third, and fifth grades and college adults were asked to make judgments of surface slant on the basis of monocular texture gradient information. Accuracy of judgment increased with increasing age. In addition, differences in gradient effectiveness were found. Compression gradients were relatively ineffective sources of information, whereas perspective and multiple gradients resulted in greater accuracy. The results suggest limitations on the specificity of certain forms of gradients.     

Handling negative inputs: On the plausible equity formulae

Equity research has been based on defining formulae that do not necessarily imply the hypotheses thought to have been derived from them and that are not consistent with empirical data cited as supporting equity theory. Neither Adams' (1965) ratio definition nor Walster et al.'s (1970, 1972, 1973) formula satisfy the fundamental criterion that, when equity holds, outcome should be an increasing function of input. Six formulae that do satisfy this fundamental criterion (including Adams' ratio definition restricted to positive ratios, Walster et al.'s revision of their formula, three formulae generated by a simple constructive procedure, and an exponential definition) are compared with respect to 11 other criteria and with respect to their predictions of the results of two thought experiments.     

Mental Imagery and Post-Event Processing in Anticipation of a Speech Performance Among Socially Anxious Individuals

The present study investigated whether post-event processing (PEP) involving mental imagery about a past speech is particularly detrimental for socially anxious individuals who are currently anticipating giving a speech. One hundred fourteen high and low socially anxious participants were told they would give a 5 min impromptu speech at the end of the experimental session. They were randomly assigned to one of three manipulation conditions: post-event processing about a past speech incorporating imagery (PEP-Imagery), semantic post-event processing about a past speech (PEP-Semantic), or a control condition, (n = 19 per experimental group, per condition [high vs low socially anxious]). After the condition inductions, individuals’ anxiety, their predictions of performance in the anticipated speech, and their interpretations of other ambiguous social events were measured. Consistent with predictions, high socially anxious individuals in the PEP-Imagery condition displayed greater anxiety than individuals in the other conditions immediately following the induction and before the anticipated speech task. They also interpreted ambiguous social scenarios in a more socially anxious manner than socially anxious individuals in the control condition. High socially anxious individuals made more negative predictions about their upcoming speech performance than low anxious participants in all conditions. The impact of imagery during post-event processing in social anxiety and its implications are discussed.