Squirrel monkeys (Saimiri sciureus) choose smaller food arrays: long-term retention, choice with nonpreferred food, and transposition

Squirrel monkeys (Saimiri sciureus) that had learned to reach toward 1 piece of food instead of 4 in a reverse-reward contingency were tested after an 8-month delay with no intervening relevant experiences. All monkeys except 1 continued to show inhibitory control by reliably reaching toward the smaller quantity, most of them doing so within 2 sessions. Performance was maintained when a low-preference food replaced prized foods as arrays and rewards. When the quantities 1 and 4 were replaced with different ones, there was strong evidence of transposition at group level, although individual differences in bias toward the smaller quantities became apparent. Individual differences in mastering the original task more than 8 months previously were quite stable, suggesting robustness in the operations required for this form of self-control.     

Attention during adaptation weakens negative afterimages

The effect of attention during adaptation on subsequent negative afterimages was examined. One of 2 overlapped outline figures was attended during a 7-10-s adaptation period. When the figures were readily perceptually segregated (on the basis of color or motion), the subsequent afterimages were initially weaker for the previously attended figure. This effect was confirmed by demonstrations that the onset of a single afterimage was delayed when an afterimage inducer was attended during adaptation compared with when a central digit stream or an overlapped (brightness-balanced) figure that did not generate an afterimage was attended. The attention effect was further confirmed using a criterion-independent (dot-integration) paradigm. The fact that selective attention during adaptation weakened or delayed afterimages suggests that attention primarily facilitates the adaptation of polarity-independent processes that modulate the visibility of afterimages rather than facilitating the adaptation of polarity-selective processes that mediate the formation of afterimages.     

Surreptitiously projecting different movies to two subsets of viewers

A new technique (manipulation of overlapping rivalrous images by polarizing filters, or MORI) has been invented for presenting on the same screen two different images that can be seen separately by two groups of viewers without their noticing the overlap. It can easily create desired artificial conflicts among viewers. Two perpendicular polarizing filters provide separate invisible channels from dual video projectors to two groups of viewers on a single screen. The basic principle of the presentation technique, details of the apparatus, and limitations are introduced. As an example of the application of this technique, an eyewitness experiment is briefly reported. The results of experiments conducted by the author and colleagues provide evidence of the effectiveness of this technique with various projectors, video materials, group sizes, and ages of participants.     

Algebraic Kripke Sheaf Semantics for Non-Classical Predicate Logics

In so-called Kripke-type models, each sentence is assigned either to true or to false at each possible world. In this setting, every possible world has the two-valued Boolean algebra as the set of truth values. Instead, we take a collection of algebras each of which is attached to a world as the set of truth values at the world, and obtain an extended semantics based on the traditional Kripke-type semantics, which we call here the algebraic Kripke semantics. We introduce algebraic Kripke sheaf semantics for super-intuitionistic and modal predicate logics, and discuss some basic properties. We can state the Gödel-McKinsey-Tarski translation theorem within this semantics. Further, we show new results on super-intuitionistic predicate logics. We prove that there exists a continuum of super-intuitionistic predicate logics each of which has both of the disjunction and existence properties and moreover the same propositional fragment as the intuitionistic logic.     

Mapping of interneurons that contribute to food aversive conditioning in the slug brain

To determine the distribution of neurons that contribute to memory formation induced by odor-taste associative conditioning in the slug's brain, we examined neuronal activity of the central nervous system of the slug Limax marginatus using a fluorescent activity marker [Lucifer yellow (LY)]. When LY was injected into the body cavity just after the conditioning, many of the procerebral (PC) interneurons were labeled. The PC lobe was considered to play important roles in the olfaction of the slug, because the olfactory afferent fibers from both the inferior and the superior tentacular noses innervate it. Such strong dye-uptake activity of PC interneurons was not observed when LY was injected just after unpaired control treatment. Thus, it was suggested that enhancement of dye-uptake activity upon conditioning was caused by the association of a conditioning stimulus (CS) with an unconditioned stimulus (UCS). The distribution patterns of PC interneurons that were labeled by LY after conditioning showed a characteristic feature: They usually formed a belt-shaped cluster parallel to the dorsoventral axis. This feature of the distribution was maintained when different odors were used as a CS. Furthermore, the number of the clusters reflected the number of CS odors but not the number of conditioning sessions. From these observations, we considered that enhancement of the neural activity involving dye uptake in each belt-shaped cluster contributed to formation of each odor memory.     

Egalitarian sex role attitudes: Scale development and comparison of American and Japanese women

The English Form of the Scale of Egalitarian Sex Role Attitudes was administered to 238 American women after the original Japanese Form was developed and administered to 420 Japanese women. The results reveal that the English Form has a potential for use as a measurement of American women's sex role attitudes. The results of cross-cultural comparisons suggest that American women have more egalitarian attitudes than their Japanese counterparts. However, they have basically similar attitudes toward more general egalitarian values. Among the four roles of woman, wife, mother, and person, the majority of the American women choose person as the most important role, whereas the Japanese women do not claim any clear dominant role. But the results show that the Japanese women's attitudes toward women's roles have become more egalitarian and individualistic during the past two decades.This research was partly supported by a grant from the Dentsu Corporation's Yoshida Hideo Memorial Foundation. The author wishes to thank Roger Brown, Cynthia Chataway, Matina Horner, Ellen Langer, and Annemette Sorensen, Yoshiyasu Uno, and the reviewers for their critical and helpful comments on an earlier version of this article. The statistical help by Ellen Herbener and Valerie Leiter are gratefully acknowledged.     

Pigeons (Columba livia) integrate visual motion using the vector average rule: effect of viewing distance

Animal Cognition - Integrating local motion signals detected by the primary motion detector is crucial for representing a rigid, two-dimensional motion. The nature of motion integration has been...     

Effects of visual-field inversions on the reverse-perspective illusion

The 'reverse-perspective' illusion entails the apparent motion of a stationary scene painted in relief and containing misleading depth cues. We have found that, using prism goggles to induce horizontal or vertical visual-field reversals, the illusory motion is greatly reduced or eliminated in the direction for which the goggles reverse the visual field. We argue that the illusion is a consequence of the observer's inability to reconcile changes in visual information due to body movement with implicit knowledge concerning anticipated changes. As such, the reverse-perspective illusion may prove to be useful in the study of the integration of linear perspective and motion parallax information.     

Understanding of the relationship between seeing and knowing by tufted capuchin monkeys (Cebus apella)

The ability of four tufted capuchin monkeys (Cebus apella) to recognize the causal connection between seeing and knowing was investigated. The subjects were trained to follow a suggestion about the location of hidden food provided by a trainer who knew where the food was (the knower) in preference to a trainer who did not (the guesser). The experimenter baited one of three opaque containers behind a cardboard screen so that the subjects could not see which of the containers hid the reward. In experiment 1, the knower appeared first in front of the apparatus and looked into each container; next, the guesser appeared but did not look into any containers. Then the knower touched the correct cup while the guesser touched one of the three randomly. The capuchin monkeys gradually learned to reach toward the cup that the knower suggested. In experiment 2, the subjects adapted to a novel variant of the task, in which the guesser touched but did not look into any of the containers. In experiment 3, the monkeys adapted again when the knower and the guesser appeared in a random order. These results suggest that capuchin monkeys can learn to recognize the relationship between seeing and knowing. Accepted after revision: 10 September 2001 Electronic Publication     

Observing emotion in infants: facial expression,body behavior,and rater judgments of responses to an expectancy-violating event

Eleven-month-old European-American, Japanese, and Chinese infants (ns = 23, 21, and 15, respectively) were videotaped during baseline and stimulus episodes of a covert toy-switch procedure. Infants looked longer at the object during the expectancy-violating event (stimulus episode) but did not produce more surprise-related facial expressions. American and Japanese infants produced more bodily stilling during stimulus than baseline, and American infants also produced more facial sobering. Naive raters viewing both episodes could correctly identify the expectancy-violating event. Rater judgments of surprise were significantly related to infants' bodily stilling and facial sobering. Judgments of interest were related to cessation of fussing. Thus, observer judgments of infant emotions can be systematically related to behaviors other than prototypic emotional facial expressions.