The reinforcing properties of aggressive vs nonaggressive social interactions in isolated male ICR mice (Mus musculus)

Isolated male ICR mice in a T-maze consistently selected the goal box which enabled them to fight another mouse if the alternative goal box allowed no social interaction (Experiment 1). However, if the alternative choice enabled the isolated mice to interact with another mouse through a mesh screen which prevented fighting, the preference for the opportunity to fight did not appear (Experiment 2). Because the visual, olfactory, and auditory stimuli available through the screen appeared to be as attractive as the stimuli provided by the additional opportunity to fight, it is not necessary to conclude that the stimuli reinforcing the choice behavior in Experiment 1 were provided by fighting. Since there is no compelling reason to conclude that fighting is a primary reinforcer for these isolated mice, it is not necessary to argue that the high incidence of isolation-induced fighting is the reflection of a primary aggressive motive.     

The role of video coherence on object-based motion discriminations by pigeons

Two experiments examined the effects of video coherence on the discrimination of relative motion by pigeons using a go/no-go procedure. Pigeons were trained to discriminate video stimuli in which the camera's perspective went either "around" or "through" the interior opening of 2 approaching objects. Experiment 1 used a within-groups design and Experiment 2 used a between-groups design to examine how sequencing these videos in a coherent smooth forward order versus a randomly scrambled order influenced learning. Discrimination learning was significantly faster with the coherent sequences. It is suggested that the pigeon visual system integrates 3-dimensional motion signals across space and time to produce a stable, object-based, perceptual world.     

Modification of the punishing effects of psychoactive drugs in rats by previous drug experience.

In Experiment 1, it was shown that chronic prior exposure to amphetamine attenuated the conditioned avoidance of saccharin that was produced by both amphetamine and morphine during gustatory conditioning trials; the relationship between morphine and amphetamine was somewhat anomalous because of their pharmacological dissimilarity. The relationship was also asymmetrical, since in Experiment 2, chronic prior exposure to morphine failed to mitigate avoidance conditioning by amphetamine but was effective in attenuating conditioning by morphine itself. In a third experiment, it was found that prior treatment with chlordiazepoxide attenuated saccharin avoidance conditioned by chlordiazepoxide but not by amphetamine or morphine. The findings were related to Parker, Failor, and Weidman's hypothesis, based on findings with morphine, concerning the development of conditioned preferences for substances associated with the repletion of artificially induced biological needs. It was suggested that the findings were best interpreted as a reflection of drug tolerance rather than conditioned preference.     

Conditioned discrimination of airborne odorants by garter snakes (Thamnophis radix and T. sirtalis sirtalis)

For snakes, the nasal chemical senses are critical in intraspecific communication and prey recognition. Although it is known that garter snakes can respond differentially to airborne odorants, no previous study has demonstrated that snakes can learn a task with airborne odors as discriminative stimuli. In Experiment 1, 7 plains garter snakes (Thamnophis radix) were trained in a two-choice apparatus to move into a compartment containing lemon-scented chips for a food reward. All 7 snakes improved performance when the first 10 and last 10 trials of the 100 trials of conditioning were compared. Four of the snakes were subsequently trained to move away from the scented compartment into the unscented compartment. The 4 snakes rapidly learned this reversal. In Experiment 2, 7 common garter snakes (T. sirtalis sirtalis) were trained to traverse a two-choice maze with the presence or absence of amyl acetate odor as the conditioned stimulus. The snakes were pretested for odor versus nonodor preference and were trained to go to the initially nonpreferred stimulus. Of the 7 snakes, 5 achieved a predetermined criterion (two training sessions with cumulative correct responding above the .05 confidence level) within 85 trials.     

Preliminary investigation of a video-based stimulus preference assessment

Video clips may be an effective format for presenting complex stimuli in preference assessments. In this preliminary study, we evaluated the correspondence between preference hierarchies generated from preference assessments that included either toys or videos of the toys. The top-ranked item corresponded in both assessments for 5 of the 6 participants, and the top- and bottom-ranked items corresponded for 4 participants. The implications of these results for future research on video preference assessments are discussed.     

The discrimination of natural movement by budgerigars (Melopsittacus undulates) and pigeons (Columba livia)

Three experiments examined the ability of birds to discriminate between the actions of walking forwards and backwards as demonstrated by video clips of a human walking a dog. Experiment 1 revealed that budgerigars (Melopsittacus undulates) could discriminate between these actions when the demonstrators moved consistently from left to right. Test trials then revealed that the discrimination transferred, without additional training, to clips of the demonstrators moving from right to left. Experiment 2 replicated the findings from Experiment 1 except that the demonstrators walked as if on a treadmill in the center of the display screen. The results from the first 2 experiments were replicated with pigeons in Experiment 3. The results cannot be explained if it is assumed that animals rely on static cues, such as those derived from individual postures, in order to discriminate between the actions of another animal. Instead, this type of discrimination appears to be controlled by dynamic cues derived from changes in the posture of the demonstrators.     

Do dogs (Canis familiaris) show contagious yawning?

We report an experimental investigation into whether domesticated dogs display contagious yawning. Fifteen dogs were shown video clips of (1) humans and (2) dogs displaying yawns and open-mouth expressions (not yawns) to investigate whether dogs showed contagious yawning to either of these social stimuli. Only one dog performed significantly more yawns during or shortly after viewing yawning videos than to the open-mouth videos, and most of these yawns occurred to the human videos. No dogs showed significantly more yawning to the open-mouth videos (human or dog). The percentage of dogs showing contagious yawning was less than chimpanzees and humans showing this behavior, and considerably less than a recently published report investigating this behavior in dogs (Joly-Mascheroni et al. in Biol Lett 4:446–448, 2008).     

Reexamination of contextual conditioning with massed versus distributed unconditioned stimuli

Sprague-Dawley rats were placed in the black compartment of a 2 compartment choice apparatus and received a series of unsignaled footshocks at fixed intertrial intervals (ITIs), with ITI duration varied across groups. Contextual conditioning was assessed using place preference and freezing tests. In Experiments 1 and 3, time spent in the unshocked, white compartment in a preference test decreased monotonically with increasing ITI. In Experiment 2, less freezing occurred in the 3-s than in the 60-s groups. An inverted U-shaped relationship between ITI and freezing emerged when a full range of ITIs was used in Experiment 3. The results have implications for the learning-performance distinction and suggest that short ITIs may promote contextual conditioning.     

Comparison of arousal and preference assessment outcomes for sex offenders with intellectual disabilities

We compared outcomes of arousal and preference assessments for five adult male alleged sexual offenders with intellectual disabilities. Arousal assessments involved the use of the penile plethysmograph to measure changes in penile circumference to both deviant (males and females under the age of 18) and nondeviant (males and females over the age of 18) video clips. Paired‐stimulus preference assessments were arranged to present still images from the video clips used in the arousal assessments. Results showed correspondence between the assessments for four out of the five participants. Implications are discussed for the use of preference assessment methodology as a less intrusive assessment approach for sexual offender assessments.     

Effects of Change in Social Content of Video Rewards on Response Patterns of Bonnet Macaques

Three individually housed bonnet macaques, with long-term experience in performing a joystick task with a reward choice of either viewing color video of a single bonnet group or obtaining a banana-flavored food treat, were presented with images of a new group when they chose to view social video. The change produced absolute increases in responding for social video and enhanced preference for viewing social video relative to obtaining the food treat, supporting the view that the monkeys were strongly attending to the social content of the videos.     

Gaze allocation in a dynamic situation: effects of social status and speaking

Human visual attention operates in a context that is complex, social and dynamic. To explore this, we recorded people taking part in a group decision-making task and then showed video clips of these situations to new participants while tracking their eye movements. Observers spent the majority of time looking at the people in the videos, and in particular at their eyes and faces. The social status of the people in the clips had been rated by their peers in the group task, and this status hierarchy strongly predicted where eye-tracker participants looked: high-status individuals were gazed at much more often, and for longer, than low-status individuals, even over short, 20-s videos. Fixation was temporally coupled to the person who was talking at any one time, but this did not account for the effect of social status on attention. These results are consistent with a gaze system that is attuned to the presence of other individuals, to their social status within a group, and to the information most useful for social interaction.     

Implicit memory for negative and positive social information in individuals with and without social anxiety

Studies of memory bias for threat-relevant information in individuals with social anxiety have produced mixed results. These discrepancies may be because investigators have studied different memory processes or have used different memory tasks. We employed a video clarity judgement task to investigate implicit (capacity-free, automatic, unconscious) memory and a recognition task to investigate explicit (effortful, strategic, conscious) memory for threat in socially anxious individuals and nonanxious controls. Implicit memory for "old" (i.e., seen before) videos was defined as rating "old" videos as more clear than "new" (i.e., never seen before) videos. We created brief video clips that involved an actor or actress approaching the camera and commenting on some aspect of the viewer's actions, physical appearance, or belongings. Twenty-four videos were positive (e.g., "I really like your shoes"), and 24 were negative (e.g., "That is a horrible haircut"). Results revealed that the video clarity test was an effective measure of implicit memory. Furthermore, socially anxious individuals showed a larger implicit memory index for negative videos than did nonanxious and dysphoric controls. No group differences emerged for implicit memory for positive videos. Similarly, groups did not differ in recognition of, or false alarms for, positive and negative videos. These results demonstrate the role of implicit memory in social anxiety implying that information about threat may be automatically primed in these individuals.     

Visual discrimination in an orangutan (Pongo pygmaeus): measuring visual preference

Although previous studies have confirmed that trained orangutans visually discriminate between mammals and artificial objects, whether orangutans without operant conditioning can discriminate remains unknown. The visual discrimination ability in an orangutan (Pongo pygmaeus) with no experience in operant learning was examined using measures of visual preference. Sixteen color photographs of inanimate objects and of mammals with four legs were randomly presented to an orangutan. The results showed that the mean looking time at photographs of mammals with four legs was longer than that for inanimate objects, suggesting that the orangutan discriminated mammals with four legs from inanimate objects. The results implied that orangutans who have not experienced operant conditioning may possess the ability to discriminate visually.     

Visual discrimination of normal and drug induced behavior in quails (<Emphasis Type="Italic">Coturnix coturnix japonica</Emphasis>)

The ability to discriminate the physical states of others could be an adaptive behavior, especially for social animals. For example, the ability to discriminate illness behavior would be helpful for avoiding spoiled foods. We report on an experiment with Japanese quails testing whether these birds can discriminate the physical states of conspecifics. The quails were trained to discriminate between moving video images of quails injected with psychoactive drugs and those in a normal (not injected) condition. Methamphetamine (stimulant) or ketamine (anesthetic) were used to produce drug-induced behaviors in conspecifics. The former induced hyperactive behavior and the latter hypoactive behavior. The subject quails could learn the discrimination and showed generalization to novel images of the drug-induced behaviors. They did not, however, show discriminative behavior according to the type and dosage of the drugs. Thus, they categorized the behavior not on the basis of degree of activity, but on the basis of abnormality.     

The Editing Density of Moving Images Influences Viewers’ Time Perception: The Mediating Role of Eye Movements

The present study examined whether cinematographic editing density affects viewers’ perception of time. As a second aim, based on embodied models that conceive time perception as strictly connected to the movement, we tested the hypothesis that the editing density of moving images also affects viewers’ eye movements and that these later mediate the effect of editing density on viewers’ temporal judgments. Seventy participants watched nine video clips edited by manipulating the number of cuts (slow- and fast-paced editing against a master shot, unedited condition). For each editing density, multiple video clips were created, representing three different kinds of routine actions. The participants’ eye movements were recorded while watching the video, and the participants were asked to report duration judgments and subjective passage of time judgments after watching each clip. The results showed that participants subjectively perceived that time flew more while watching fast-paced edited videos than slow-paced or unedited videos; by contrast, concerning duration judgments, participants overestimated the duration of fast-paced videos compared to the master-shot videos. Both the slow- and the fast-paced editing generated shorter fixations than the master shot, and the fast-paced editing led to shorter fixations than the slow-paced editing. Finally, compared to the unedited condition, editing led to an overestimation of durations through increased eye mobility. These findings suggest that the editing density of moving images by increasing the number of cuts effectively altered viewers’ experience of time and add further evidence to prior research showing that performed eye movement is associated with temporal judgments.     

Visual experience influences 12-month-old infants' perception of goal-directed actions of others

In the present study, we investigated whether infants' own visual experiences affected their perception of the visual status of others engaging in goal-directed actions. In Experiment 1, infants viewed video clips of successful and failed goal-directed actions performed by a blindfolded adult, with half the infants having previously experienced being blindfolded. The results showed that 12-month-old infants who were previously blindfolded preferred to look longer at the demonstrator's successful actions, whereas no such preference was observed in 8-month-old infants. In Experiment 2, infants watched the same 2 actions when the adult demonstrator was not blindfolded. The responses of 12-month-old infants were the opposite of those observed in Experiment 1: they showed a preference for the failed actions. These findings suggest that previous experience influenced the subsequent perception of others' goal-directed actions in the 12-month-old infants. We favor the interpretation that the preference for the successful actions in the 12-months-old infants provided with blindfolded experience demonstrates the influence of perceptual experience on considering the visual status of others engaging in goal-directed actions.     

Discriminating languages by speech-reading

The goal of this study was to explore the ability to discriminate languages using the visual correlates of speech (i.e., speech-reading). Participants were presented with silent video clips of an actor pronouncing two sentences (in Catalan and/or Spanish) and were asked to judge whether the sentences were in the same language or in different languages. Our results established that Spanish-Catalan bilingual speakers could discriminate running speech from their two languages on the basis of visual cues alone (Experiment 1). However, we found that this ability was critically restricted by linguistic experience, since Italian and English speakers who were unfamiliar with the test languages could not successfully discriminate the stimuli (Experiment 2). A test of Spanish monolingual speakers revealed that knowledge of only one of the two test languages was sufficient to achieve the discrimination, although at a lower level of accuracy than that seen in bilingual speakers (Experiment 3). Finally, we evaluated the ability to identify the language by speech-reading particularly distinctive words (Experiment 4). The results obtained are in accord with recent proposals arguing that the visual speech signal is rich in informational content, above and beyond what traditional accounts based solely on visemic confusion matrices would predict.     

Thin-slice perception develops slowly

Body language and facial gesture provide sufficient visual information to support high-level social inferences from "thin slices" of behavior. Given short movies of nonverbal behavior, adults make reliable judgments in a large number of tasks. Here we find that the high precision of adults' nonverbal social perception depends on the slow development, over childhood, of sensitivity to subtle visual cues. Children and adult participants watched short silent clips in which a target child played with Lego blocks either in the (off-screen) presence of an adult or alone. Participants judged whether the target was playing alone or not; that is, they detected the presence of a social interaction (from the behavior of one participant in that interaction). This task allowed us to compare performance across ages with the true answer. Children did not reach adult levels of performance on this task until 9 or 10 years of age, and we observed an interaction between age and video reversal. Adults and older children benefitted from the videos being played in temporal sequence, rather than reversed, suggesting that adults (but not young children) are sensitive to natural movement in social interactions.     

Discrimination of moving video images of self by pigeons (<Emphasis Type="Italic">Columba livia</Emphasis>)

The ability to recognize self has been known to be limited to some animal species, but previous research has focused almost exclusively on the animal's reaction to a mirror. Recent studies suggest that the temporal contingency between a subject's action and the corresponding visual scene reflected in a mirror plays an important role in self-recognition. To assess the roles of visual-proprioceptive contiguity in self-recognition, we explored whether pigeons are able to discriminate videos of themselves with various temporal properties. We trained five pigeons to respond to live video images of themselves (live self-movies) and not to video filmed during previous training sessions (pre-recorded self-movies). Pigeons learned to peck trial-unique live self-movies more frequently than pre-recorded self-movies. We conducted two generalization tests after pigeons learned to discriminate between the two conditions. First, discrimination acquired during training sessions was transferred to a test session involving live self-movies and new pre-recorded self-movies. Second, the same pigeons were tested in extinction procedure using delayed live self-movies and new pre-recorded self-movies. Although pigeons responded to delayed presentations of live self-movies more frequently than to new pre-recorded self-movies, the relative response rate to delayed presentation of live self-movies gradually decreased as the temporal discrepancy between pigeons' own behavior and the corresponding video increased. These results indicate that pigeons' discrimination of self-movies with various temporal properties was based on the temporal contiguity between their behavior and its visual feedback. The methodology used in the present experiment is an important step toward improving the experimental analysis of self-recognition in non-human animals.