Quantity-based judgments in the domestic dog (<Emphasis Type="Italic">Canis lupus familiaris</Emphasis>)

We examined the ability of domestic dogs to choose the larger versus smaller quantity of food in two experiments. In experiment 1, we investigated the ability of 29 dogs (results from 18 dogs were used in the data analysis) to discriminate between two quantities of food presented in eight different combinations. Choices were simultaneously presented and visually available at the time of choice. Overall, subjects chose the larger quantity more often than the smaller quantity, but they found numerically close comparisons more difficult. In experiment 2, we tested two dogs from experiment 1 under three conditions. In condition 1, we used similar methods from experiment 1 and tested the dogs multiple times on the eight combinations from experiment 1 plus one additional combination. In conditions 2 and 3, the food was visually unavailable to the subjects at the time of choice, but in condition 2, food choices were viewed simultaneously before being made visually unavailable, and in condition 3, they were viewed successively. In these last two conditions, and especially in condition 3, the dogs had to keep track of quantities mentally in order to choose optimally. Subjects still chose the larger quantity more often than the smaller quantity when the food was not simultaneously visible at the time of choice. Olfactory cues and inadvertent cuing by the experimenter were excluded as mechanisms for choosing larger quantities. The results suggest that, like apes tested on similar tasks, some dogs can form internal representations and make mental comparisons of quantity.     

Output order in immediate serial recall

In two experiments, we examined the effect of output order in immediate serial recall (ISR). In Experiment 1, three groups of participants saw lists of eight words and wrote down the words in the rows corresponding to their serial positions in an eight-row response grid. One group was precued to respond in forward order, a second group was precued to respond in any order, and a third group was postcued for response order. There were significant effects of output order, but not of cue type. Relative to the forward output order, the free output order led to enhanced recency and diminished primacy, with superior performance for words output early in recall. These results were replicated in Experiment 2 using six-item lists, which further suggests that output order plays an important role in the primacy effect in ISR and that the recency items are most highly accessible at recall.     

Multiple measures of hand-use lateralization in the ring-tailed lemur (Lemur catta)

Evaluated a free-ranging matriline of 13 ring-tailed lemurs (Lemur catta) from videotaped records for lateralized hand use with 2 tasks and 4 measures: food reaching, feeding posture, duration of food holding, and manipulation of food between mouth and hand while eating. Binomial z scores determined 7 lemurs to be left preferent in reaching, 3 right, and 3 ambipreferent. Ideographic analyses suggested possible sex-linked and early experience twin effects. When compared to right and ambipreferent lemurs, left reach preferent lemurs used the left hand more but bimanuals grasped less in food holding and also engaged in less hand-mouth food manipulation. The tendency to manipulate food was not correlated with bimanual holding but was inversely related to left hand holding and directly related to right hand holding. These patterns are discussed as possible precursors of human bimanual manipulation.     

The effects of classwide peer tutoring on correct cardiopulmonary resuscitation performance by physical education majors

Previous research conducted on the effectiveness of basic life support skills courses has reported that participants typically do not achieve correct performance of life support skills. We used a multiple baseline design across subjects to assess the effects of a classwide peer tutoring intervention on the correct cardiopulmonary resuscitation skills of ten physical education majors. The classwide peer tutoring intervention consisted of (a) a checklist, (b) a prompting procedure, and (c) immediate feedback on performance. Procedural fidelity measures were taken on the correct implementation of the basic life supports skill course and on the implementation of the classwide peer tutoring intervention. Results indicated that students achieved and maintained 100% correct performance during the classwide per tuition condition. These results challenge the current polices of the American Red Cross and the American Heart Association who have reduced course performance criteria because participants were not achieving an adequate standard of performance.     

Temporal constraints on the McGurk effect

Three experiments are reported on the influence of different timing relations on the McGurk effect. In the first experiment, it is shown that strict temporal synchrony between auditory and visual speech stimuli is not required for the McGurk effect. Subjects were strongly influenced by the visual stimuli when the auditory stimuli lagged the visual stimuli by as much as 180 msec. In addition, a stronger McGurk effect was found when the visual and auditory vowels matched. In the second experiment, we paired auditory and visual speech stimuli produced under different speaking conditions (fast, normal, clear). The results showed that the manipulations in both the visual and auditory speaking conditions independently influenced perception. In addition, there was a small but reliable tendency for the better matched stimuli to elicit more McGurk responses than unmatched conditions. In the third experiment, we combined auditory and visual stimuli produced under different speaking conditions (fast, clear) and delayed the acoustics with respect to the visual stimuli. The subjects showed the same pattern of results as in the second experiment. Finally, the delay did not cause different patterns of results for the different audiovisual speaking style combinations. The results suggest that perceivers may be sensitive to the concordance of the time-varying aspects of speech but they do not require temporal coincidence of that information.     

PRIMING FROM THE ATTENTIONAL BLINK:

Abstract —When people must detect several targets in a very rapid stream of successive visual events at the same location, detection of an initial target induces misses for subsequent targets within a brief period. This attentional blink may serve to prevent interruption of ongoing target processing by temporarily suppressing vision for subsequent stimuli. We examined the level at which the internal blink operates, specifically, whether it prevents early visual processing or prevents quite substantial processing from reaching awareness. Our data support the latter view. We observed priming from missed letter targets, benefiting detection of a subsequent target with the same identity but a different case. In a second study, we observed semantic priming from word targets that were missed during the blink. These results demonstrate that attentional gating within the blink operates only after substantial stimulus processing has already taken place. The results are discussed in terms of two forms of visual representation, namely, types and tokens.     

Mixed-method mixed-modality psychophysical scaling

Four experiments are reported in which the direct psychophysical scaling methods of magnitude estimation, category judgment, and cross-modality matching were mixed in the same series of trials, both with a single stimulus modality and in a mixed-modality situation. The mixed-method scaling situation gave results consistent with those obtained when methods are used alone, and it has several advantages. Interactions between the methods were consistent with the idea that judgments made under all three are mediated by a primitive process of categorization that is influenced by heuristics used to achieve a single category identity for each stimulus.     

The place of social intelligence in a taxonomy of cognitive abilities

Studies have yielded inconsistent results regarding the place of social intelligence in a taxonomy of cognitive abilities. An investigation is described in which measures of social behaviors obtained from interviews were related to a wide variety of cognitive variables. Significant relations were rare. It is suggested that the question to be posed is not the simple one of the place of social intelligence in the cognitive domain but rather one of the relationships of the elements of two large taxonomic systems. A Taxonomy of social intelligence would provide a set of definitions procedures that would improve efforts to replicate and build on previous research. More important would be the heuristic value of a structural representation of “social intelligence” based on theoretical relationships involving environmental, physiological, and genetic as well as psychological factors. Development of a taxonomy of situations would facilitate the study of interactions involving performance and environmental conditions.