Effects of conspecifics on feeding in Aplysia fasciata

The presence of other Aplysia in the environment increases the time spent feeding. This finding is consistent with the hypothesis that a common arousal mechanism modulates feeding and reproductive behaviors. The arousal level is presumably increased by pheromones released by additional animals.     

Imagery and meaning,the cognitive science connection

Taking the integrated viewpoints of causal theory of reference, cognitive science and the notion of correspondence principles from physics, this paper addresses the problems of creativity, the nature of visual imagery and the manner in which science progresses.     

Attractiveness in young children: Sex-differentiated reactions of adults

Attractiveness ratings of 50 children aged 12–38 months were investigated in relation to adult socializing agents' behavior toward the children in their homes and play groups and their attitudes toward the children. Attractiveness scores were derived from 43 judges' ratings of facial photographs of the children. The same children were observed in play groups with female care givers; 40 of them were also observed in their homes with their parents. Play-group care givers rated the children for likability, tractability, and peer relations. Parents rated their attitudes toward giving routine care to their child. Attractiveness scores were not correlated with any adult attitude measures. Girls' attractiveness scores were positively correlated with their attempts to communicate in home and play group, and with mothers', fathers', and care givers' instructional responses, but negatively correlated with passive behavior in the home and with mothers' positive reactions. Boys' attractiveness scores were negatively correlated with passive behavior in the play group; no other significant correlations were found in the data for boys.     

Is there coherence among the cognitive components of gender acquisition?

This study examined the relationships among five measures that assess various cognitive components of the child's acquisition of gender. At around 2 years of age, children were given a task assessing their ability to accurately label as a boy or a girl some head-and-shoulders pictures of boys and girls. At 4 years of age, these children were given tasks measuring (1) the degree to which they found gender a salient parameter of categorization, (2) the amount of gender-related knowledge they could display (SERLI-SRD), (3) the degree to which their preferences were gender-typed (SERLI-SRP) and (4) the accuracy of their memory for gender-typed information. There was no consistent pattern of relationship among the children's scores on these five tools for measuring gender acquisition. Our findings suggest that gender is a multidimensional construct in children's development, and thus these results challenge the undimensional manner in which gender is repeatedly addressed in developmental theory and research.This research was funded in part by a federal biomedical research grant (No. 2507RR07080) awarded to the first author from the Department of Psychology at the University of Oregon, and by Grant No. RO1HD175751 from the National Institute of Child Development awarded to the third author.We wish to thank Margo Lane, Rachel Robertson, Jacqui Oucalt, Laura Baker, Dale Roberts, and the teachers, parents, and assistants of the Child Research Laboratory at the University of Oregon in Eugene, Oregon, for their invaluable contribution to this research.     

Encoding dimensions of subject-performed tasks

Summary In an experiment modelled upon the classical paradigm on release from proactive interference (PI), subjects were required to remember series of actions they had performed (e.g., roll the ball, fold the paper). The objects involved in these subject-performed tasks (SPTs) served as a basis for build-up and release of PI. The objects used in the first few trials of the experiment belonged to the same class (e.g., parts of the body), causing a build up of PI. A shift to a different class of objects (e.g., kitchen utensils) along four different dimensions (taxonomic category, weight, color, and size) was introduced to cause a release of PI. On the basis of PI-release experiments with words it was expected that shifts in taxonomic category would result in a greater release than shifts within any of the physical dimensions. However, the results revealed that the amount of PI release was, in general, larger than expected, and essentially the same for all four dimensions investigated. The results are discussed in terms of the nature of the memory representation of SPTs, and with regard to possible processing differences between SPTs and verbal information. In addition, methodological suggestions for furthering the understanding of the encoding and storage of action events are advanced.     

Conditional withholding of proboscis extension in honeybees (Apis mellifera) during discriminative punishment.

Proboscis extension conditioning of honeybee workers was used to test the ability of bees to respond to appetitive and aversive stimuli while restrained in a harness that allows subjects to move their antennae and mouthparts (Kuwabara, 1957; Menzel, Erber, & Masuhr, 1974). Subjects were conditioned to discriminate between two odors, one associated with sucrose feeding and the other associated with a 10 V AC shock if they responded to the sucrose unconditioned stimulus (US) in the context of that odor. Most Ss readily learned to respond to the odor followed by sucrose feeding and not to the odor associated with sucrose stimulation plus shock. Furthermore, in the context of the odor associated with shock, significantly more subjects withheld or delayed proboscis extension on stimulation with the sucrose US than they did in the context of the odor associated with feeding. Thus, restrained honeybees can readily learn to avoid shock according to an odor context by withholding proboscis extension to a normally powerful releaser. Analysis of individual learning curves revealed that subjects differed markedly in performance on this task. Some learn the discrimination quickly, whereas others show different kinds of response patterns.     

Acquisition of a relative class concept by an African gray parrot (Psittacus erithacus): discriminations based on relative size

We report that an African gray parrot (Psittacus erithacus), Alex, responds to stimuli on a relative basis. Previous laboratory studies with artificial stimuli (such as pure tones) suggest that birds make relational responses as a secondary strategy, only after they have acquired information about the absolute values of the stimuli. Alex, however, after learning to respond to a small set of exemplars on the basis of relative size, transferred this behavior to novel situations that did not provide specific information about the absolute values of the stimuli. He responded to vocal questions about which was the larger or smaller exemplar by vocally labeling its color or material, and he responded "none" if the exemplars did not differ in size. His overall accuracy was 78.7%.     

Social feeding reverses learned flavor aversions in spotted hyenas (Crocuta crocuta).

Spotted hyenas are highly social carnivores with competitive feeding habits. It was hypothesized that social feeding might be capable of reversing an established flavor aversion. The dominant hyena of each of 4 captive social groups was given a novel food mixed with LiCl on Day 1; aversion to this food was demonstrated on Day 2. On Day 3, the dominant hyena and 3 or 4 members of her group were offered the food simultaneously. Three of the 4 dominant hyenas ate substantial quantities of the food during this group feeding, and all 4 hyenas ate the following day when offered the food alone. In contrast, when averted to a different novel food, the hyenas refused that food on 3 consecutive days. In this species social factors, such as those operating during group feeding, are sufficiently powerful to attenuate, immediately and dramatically, a strong LiCl-induced aversion.     

Second-order conditioning of the rabbit's nictitating membrane response. Interstimulus interval and frequency of CS-CS pairings.

Second-order conditioning of the rabbit's nictitating membrane response (NMR) was investigated when second-order trials (CS1-CS2) were intermixed with first-order trials (CS2-US) from the outset of training. Experiment 1 showed that CR acquisition to CS1 was inversely related to the CS1-CS2 interval but nevertheless extended to an interval of 8,400 ms. Experiment 2 revealed that CR acquisition of CS1 was an inverted-U function of the number of CS1-CS2 trials relative to a fixed number of CS2-US trials. Experiment 3 directly contrasted second-order conditioning with a reinforced serial compound procedure (CS1-CS2-US) and a mixed procedure in which second-order trials were intermixed with the reinforced serial compound. Second-order conditioning was about half the strength of either the reinforced serial compound or the mixed procedure, which were similar. The present results are discussed with respect to the relative strength of excitatory and inhibitory processes in second-order conditioning.