The use of an escape contingency and a token economy to increase food acceptance

Escape (termination of a meal) and token-based differential reinforcement of alternative behavior were used as reinforcement to increase acceptance of food. Using a changing criterion design, the number of bites accepted and consumed was gradually increased to 15 bites per meal. These data suggest that, in some cases, escape may be a potent reinforcer for food acceptance.     

Deductive reasoning with factual, possible, and counterfactual conditionals

We compared reasoners' inferences from conditionals based on possibilities in the present or the past (e.g., "If Linda had been in Dublin then Cathy would have been in Galway") with their inferences based on facts in the present or the past (e.g., "If Linda was in Dublin then Cathy was in Galway"). We propose that people construct a richer representation of conditionals that deal with possibilities rather than facts: Their models make explicit not only the suppositional case, in which Linda is in Dublin and Cathy is in Galway, but also the presupposed case, in which Linda is not in Dublin and Cathy is not in Galway. We report the results of four experiments that corroborate this model theory. The experiments show that reasoners make more inferences from conditionals based on possibilities rather than on facts when the inferences depend on the presupposed case. The results also show that reasoners generate different situations to verify and falsify conditionals based on possibilities and facts.     

Response acquisition with delayed reinforcement: a comparison of two-lever procedures.

Groups of 8 experimentally naive rats were exposed during 8-hr sessions to resetting delay procedures in which responses on one lever (the reinforcement lever) produced water after a delay of 8, 16, 32, or 64 s. For rats in one condition, responses on a second (no-consequences) lever had no programmed consequences. For rats in another condition, responses on a second (cancellation) lever during a delay initiated by a response on the reinforcement lever prevented delivery of the scheduled reinforcer; responses on the cancellation lever at other times had no programmed consequences. Under both conditions and at all delays, most subjects emitted more responses on the reinforcement lever than did control rats that never received water emitted on either lever. At 8-s delays, both conditions engendered substantially more responding on the reinforcement lever than on the other lever, and performance closely resembled that of immediate-reinforcement controls. At delays of 16 and 32 s, however, there was clear differential responding on the two levers under the cancellation condition but not under the other condition. When the delay was 64 s, differential responding on the two levers did not occur consistently under either condition. These findings provide strong evidence that the behavior of rats is sensitive to consequences delayed by 8, 16, and 32 s, but only equivocal evidence of such sensitivity to consequences delayed 64 s. They also indicate that acquisition depends, in part, on the measure of performance used to index it.     

The effect of a contraceptive theme on response to erotica

Undergraduate students (60 males, 60 females) viewed a sexually explicit movie in which a couple engaged in intercourse. Different themes were introduced by prefacing the film with information varying the filmed couple's apparent marital status (single, married) and contraceptive practices (no information, no contraception, contraception via the pill). After viewing the movie, subjects filled out a questionnaire assessing their own affective reactions plus their perceptions and evaluations of the couple. Male subjects reported the greatest positive affect when the film couple was described as single and using contraception, but they also perceived the stimulus couple as caring the least for one another when they were using contraceptives. In contrast, females perceived contraceptive use as positive evidence of mutual caring. These sex differences in reacting to contraceptive use were discussed in terms of the relatively greater tendency of males to separate love and sex than is true for females.Work on this experiment was supported by a research grant (SOC 74-15254) from the National Science Foundation. The authors wish to thank Elizabeth Rice Allgeier, William A. Fisher, and Richard Knox for their comments and suggestions.     

Memory for urban geography

Consistent patterns of errors are found in estimations of distances and angles along urban routes, even among subjects who know the areas well. These patterns can be used to discover the organization of the knowledge we use to find our way around in everyday life.

In the first experiment, 80 undergraduates estimated by ratio scaling the walking distances between pairs of locations in St. Andrews. Routes varied independently in their location, number of major bends, and length. Relative overestimation of length was found with routes in the town centre, with routes having several major bends, and (perhaps as an experimental artifact) with short routes. In the second experiment, 30 Cambridge residents estimated the angles between pairs of roads, by drawing the configuration of roads at their junctions. The real angles were either in the range 60-70° or 110-120°. All the estimates differed little from 90°, regardless of the true magnitude of the angle.

The implications of these findings for theories of mental representation of largescale space are discussed. A model is supported in which a spatial area is represented as a “network-map”, consisting of strings of locations forming a net of paths known to be traversable, but vector distance is not preserved.     

Planning meals: Problem-solving on a real data-base

Planning the menu for a dinner party, although a familiar and practiced task, involves problem-solving with a large and complex body of knowledge. It is here used to study the everyday operation of human memory. Verbal protocol analysis, a technique devised to investigate formal problem-solving, is examined theoretically and adapted for analysis of this task. The study shows the need for a number of mental structures and their associated control processes, only some of which have previously been proposed in psychology.     

Strength of instigation as a determinant of the aggression—Attraction relationship

Somewhat surprisingly, previous research has failed to demonstrate what was thought to be an intuitively obvious negative relationship between aggression and attraction toward the victim of aggression. It was proposed that powerful instigation procedures in past research had served to obscure the effects of attraction on aggression. It was therefore hypothesized that aggression toward a stranger occurs as an inverse function of attitudinally induced attraction toward that stranger only when instigation strength is low. Male subjects (N=60) responding on the Buss aggression apparatus were exposed to a similar or dissimilar victim and to one of three levels of instigation: no instigation, a moderately aggressive model, or insulting evaluations. The hypothesized interaction between similarity and strength of instigation was confirmed for shock intensity (p<.02). For shock duration, main effects were found for both similarity (p<.02) and strength of instigation (p<.02). It was concluded that relatively negative feelings about another individual increase the probability of aggressing against him, but that such feelings do not constitute a necessary or sufficient condition for that aggression.This research was supported in part by Research Grant GS-40329 from the National Science Foundation. The authors wish to thank Dr. Don A. Nelson and Dr. Robert A. Baron for their aid in this experiment.