Mechanistic probability

I describe a realist, ontologically objective interpretation of probability, ??far-flung frequency (FFF) mechanistic probability??. FFF mechanistic probability is defined in terms of facts about the causal structure of devices and certain sets of frequencies in the actual world. Though defined partly in terms of frequencies, FFF mechanistic probability avoids many drawbacks of well-known frequency theories and helps causally explain stable frequencies, which will usually be close to the values of mechanistic probabilities. I also argue that it??s a virtue rather than a failing of FFF mechanistic probability that it does not define single-case chances, and compare some aspects of my interpretation to a recent interpretation proposed by Strevens.     

The “Mind's Eye” and Metered-Memory Search

The effects of imagery value of noun stimuli were investigated in a metered-memory search paradigm. A within-subjects design was used with two levels of imagery (high or low) and three transformation levels. Response latency increased significantly with transformation level and was significantly faster when high-imagery nouns composed the memory set. The imagery effect was not found to lead to differential search rates. The hypothesis that metered-memory search would include a component of visually regenerating the memory set and holding it for the actual search was supported. No evidence was found against the notion that the search itself was verbal in nature.     

Effects of Potential Partners' Costume and Physical Attractiveness on Sexuality and Partner Selection

Male and female college students in the United States (N = 224) viewed models who had been prerated for physical attractiveness and who were dressed in costumes representing one of three levels of socioeconomic status (SES). Subjects reported their willingness to engage with these stimulus persons in six relationships involving various levels of marital potential and sexual involvement. Models' costume status had greater effects on female subjects' willingness than on male subjects' willingness to enter all six relationships. This difference was larger when the physical attractiveness of models was low than when it was high. Costume status also affected female subjects' ratings of male models' attractiveness but did not affect male subjects' ratings of female models' attractiveness. Results supported eight hypotheses derived from evolutionary theory: In choosing partners, men and women weighed potential partners' SES and physical attractiveness differently, and these factors may have different behavioral implications depending on the degree to which sexual relations, or marital potential, or both, are involved.     

Monitoring visual activity in infant rhesus monkeys: Method and calibration

This paper describes the use of an infrared corneal reflection technique to monitor visual activity in infant rhesus monkeys. To establish the validity of the method, calibration data were collected and a mathematical correction for systematic sources of error was used.     

Post-retrieval beta-adrenergic receptor blockade: effects on extinction and reconsolidation of cocaine-cue memories

Contexts and discrete cues associated with drug-taking are often responsible for relapse among addicts. Animal models have shown that interference with the reconsolidation of drug-cue memories can reduce seeking of drugs or drug-paired stimuli. One such model is conditioned place preference (CPP) in which an animal is trained to associate a particular environment with the rewarding effects of a drug. Previous work from this laboratory has shown that intra-nucleus accumbens core infusions of a MEK inhibitor can interfere with reconsolidation of these drug-cue memories. A question that remains is whether post-retrieval drug effects on subsequent memories represent an interference with reconsolidation processes or rather a facilitation of extinction. In this experiment, we explore the effect of post-retrieval injections of propranolol, a beta-adrenergic receptor antagonist, on reconsolidation and extinction of cocaine CPP. After acquisition of cocaine CPP, animals were given post-retrieval propranolol injections once or each day during a protocol of unreinforced preference tests, until the animals showed no preference for the previously cocaine-paired environment. Following a cocaine priming injection, the animals that received daily post-test propranolol injections did not reinstate their preference for the drug-paired side. In contrast, a single post-retrieval propranolol injection followed by multiple days of unreinforced preference tests failed to blunt subsequent cocaine reinstatement of the memory. These data suggest that daily post-retrieval systemic injections of propranolol decrease the conditioned preference by interfering with reconsolidation of the memory for the association between the drug-paired side and the reinforcing effects of the drug, rather than facilitating new extinction learning.