|
Proops, L., Grounds, K., Smith, A. V., & McComb, K. (2018). Animals Remember Previous Facial Expressions that Specific Humans Have Exhibited. Current Biology, 28(9), 1428–1432.e4.
Abstract: Summary For humans, facial expressions are important social signals, and how we perceive specific individuals may be influenced by subtle emotional cues that they have given us in past encounters. A wide range of animal species are also capable of discriminating the emotions of others through facial expressions [1, 2, 3, 4, 5], and it is clear that remembering emotional experiences with specific individuals could have clear benefits for social bonding and aggression avoidance when these individuals are encountered again. Although there is evidence that non-human animals are capable of remembering the identity of individuals who have directly harmed them [6, 7], it is not known whether animals can form lasting memories of specific individuals simply by observing subtle emotional expressions that they exhibit on their faces. Here we conducted controlled experiments in which domestic horses were presented with a photograph of an angry or happy human face and several hours later saw the person who had given the expression in a neutral state. Short-term exposure to the facial expression was enough to generate clear differences in subsequent responses to that individual (but not to a different mismatched person), consistent with the past angry expression having been perceived negatively and the happy expression positively. Both humans were blind to the photograph that the horses had seen. Our results provide clear evidence that some non-human animals can effectively eavesdrop on the emotional state cues that humans reveal on a moment-to-moment basis, using their memory of these to guide future interactions with particular individuals.
|
|
|
Beaver, B. V. (1986). Aggressive behavior problems. Vet Clin North Am Equine Pract, 2(3), 635–644.
Abstract: Accurate diagnosis of the cause of aggression in horses is essential to determining the appropriate course of action. The affective forms of aggression include fear-induced, pain-induced, intermale, dominance, protective, maternal, learned, and redirected aggressions. Non-affective aggression includes play and sex-related forms. Irritable aggression and hypertestosteronism in mares are medical problems, whereas genetic factors, brain dysfunction, and self-mutilation are also concerns.
|
|
|
Hausberger, M., Bruderer, C., Le Scolan, N., & Pierre, J. - S. (2004). Interplay between environmental and genetic factors in temperament/personality traits in horses (Equus caballus). J Comp Psychol, 118(4), 434–446.
Abstract: The aim of the present study was to broach the question of the relative influence of different genetic and environmental factors on different temperament/personality traits of horses (Equus caballus). The researchers submitted 702 horses to standardized experimental tests and investigated 9 factors, either genetic or environmental. Genetic factors, such as sire or breed, seemed to influence more neophobic reactions, whereas environmental factors, such as the type of work, seemed to play a more dominant role in reactions to social separation or learning abilities. Additive effects were evident, showing how environmental factors may modulate behavioral traits. This study constitutes a first step toward understanding the relative weights of genetic factors and how the environment may intervene in determining individual behavioral characteristics.
|
|
|
Schultheiss, O. C., Riebel, K., & Jones, N. M. (2009). Activity inhibition: A predictor of lateralized brain function during stress? Neuropsychology, 23(3), 392–404.
Abstract: The authors tested the hypothesis that activity inhibition (AI), a measure of the frequency of the word “not” in written material, marks a propensity to engage functions of the right hemisphere (RH) and disengage functions of the left hemisphere (LH), particularly during stress. Study 1 and Study 2 showed that high AI predicts faster detection of stimuli presented to the RH, relative to the LH. Study 2 provided evidence that the AI-laterality effect is specific to perceptual, but not motor, laterality and that it is particularly strong in individuals with low mood, but absent in individuals in a positive mood state. Study 3 showed that negative affective stimuli prime the AI-laterality effect more strongly than positive affective stimuli. Findings from Study 4 suggest that situationally induced frustration (losing a contest), in conjunction with high AI, leads to increased attentional laterality. The present findings substantially bolster the construct validity of AI and contribute to a better understanding of earlier findings linking AI to physiological stress responses, immune system functioning, alcohol abuse, and nonverbal behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
|
|
|
Larose, C., Richard-Yris, M. - A., Hausberger, M., & Rogers, L. J. (2006). Laterality of horses associated with emotionality in novel situations. Laterality, 11(4), 355–367.
Abstract: We have established that lateral biases are characteristic of visual behaviour in 65 horses. Two breeds, Trotters and French Saddlebreds aged 2 to 3, were tested on a novel object test. The main finding was a significant correlation between emotionality index and the eye preferred to view the novel stimulus: the higher the emotionality, the more likely that the horse looked with its left eye. The less emotive French Saddlebreds, however, tended to glance at the object using the right eye, a tendency that was not found in the Trotters, although the emotive index was the same for both breeds. The youngest French Saddlebreds did not show this trend. These results are discussed in relation to the different training practices for the breeds and broader findings on lateralisation in different species.
|
|
|
Sato, W., & Aoki, S. (2006). Right hemispheric dominance in processing of unconscious negative emotion. Brain and Cognition, 62(3), 261–266.
Abstract: Right hemispheric dominance in unconscious emotional processing has been suggested, but remains controversial. This issue was investigated using the subliminal affective priming paradigm combined with unilateral visual presentation in 40 normal subjects. In either left or right visual fields, angry facial expressions, happy facial expressions, or plain gray images were briefly presented as negative, positive, and control primes, followed by a mosaic mask. Then nonsense target ideographs were presented, and the subjects evaluated their partiality toward the targets. When the stimuli were presented in the left, but not the right, visual fields, the negative primes reduced the subjects' liking for the targets, relative to the case of the positive or control primes. These results provided behavioral evidence supporting the hypothesis that the right hemisphere is dominant for unconscious negative emotional processing.
|
|
|
Kalin, N. H., & Shelton, S. E. (2003). Nonhuman primate models to study anxiety, emotion regulation, and psychopathology. Ann N Y Acad Sci, 1008, 189–200.
Abstract: This paper demonstrates that the rhesus monkey provides an excellent model to study mechanisms underlying human anxiety and fear and emotion regulation. In previous studies with rhesus monkeys, stable, brain, endocrine, and behavioral characteristics related to individual differences in anxiety were found. It was suggested that, when extreme, these features characterize an anxious endophenotype and that these findings in the monkey are particularly relevant to understanding adaptive and maladaptive anxiety responses in humans. The monkey model is also relevant to understanding the development of human psychopathology. For example, children with extremely inhibited temperament are at increased risk to develop anxiety disorders, and these children have behavioral and biological alterations that are similar to those described in the monkey anxious endophenotype. It is likely that different aspects of the anxious endophenotype are mediated by the interactions of limbic, brain stem, and cortical regions. To understand the brain mechanisms underlying adaptive anxiety responses and their physiological concomitants, a series of studies in monkeys lesioning components of the neural circuitry (amygdala, central nucleus of the amygdala and orbitofrontal cortex) hypothesized to play a role are currently being performed. Initial findings suggest that the central nucleus of the amygdala modulates the expression of behavioral inhibition, a key feature of the endophenotype. In preliminary FDG positron emission tomography (PET) studies, functional linkages were established between the amygdala and prefrontal cortical regions that are associated with the activation of anxiety.
|
|
|
Seyfarth, R. M., & Cheney, D. L. (2003). Signalers and receivers in animal communication. Annu Rev Psychol, 54, 145–173.
Abstract: In animal communication natural selection favors callers who vocalize to affect the behavior of listeners and listeners who acquire information from vocalizations, using this information to represent their environment. The acquisition of information in the wild is similar to the learning that occurs in laboratory conditioning experiments. It also has some parallels with language. The dichotomous view that animal signals must be either referential or emotional is false, because they can easily be both: The mechanisms that cause a signaler to vocalize do not limit a listener's ability to extract information from the call. The inability of most animals to recognize the mental states of others distinguishes animal communication most clearly from human language. Whereas signalers may vocalize to change a listener's behavior, they do not call to inform others. Listeners acquire information from signalers who do not, in the human sense, intend to provide it.
|
|
|
Laister, S., Stockinger, B., Regner, A. - M., Zenger, K., Knierim, U., & Winckler, C. (2011). Social licking in dairy cattle--Effects on heart rate in performers and receivers. Appl. Anim. Behav. Sci., 130(3-4), 81–90.
Abstract: Using heart rate (HR) measurements we investigated whether potential calming effects of social licking were evident for both active (performers) and passive (receivers) licking partners. A HR decline was assumed to indicate relaxation and thus the experience of positive emotions. Effects of the licking category (spontaneous, solicited), the animals' basic activity (standing, lying) and the licked body region (head, neck, rest) were also considered. Two studies (A, B) were carried out in the same loose housed Austrian Simmental dairy herd. HR was recorded in up to 20 focal animals on 16 and 18 days, respectively. Using either direct observations (A) or video recordings (B), social licking interactions were continuously observed. The cow's basic activity was recorded using scan sampling at 5 min intervals. Linear mixed effects models were applied separately for Study A and B in order to compare the mean HR of the licking bouts with the mean of the respective 5 min pre- and post-licking periods. In receivers we found a significant calming effect in terms of a HR decline during allogrooming in both studies (A: -1.3 beats per minute, B: -1.1 bpm). This effect was more pronounced when animals were standing (A/B: -2.4 bpm/-3.8 bpm). However, it was not affected by the licked body region. In dairy cows performing social licking, we did not find an overall calming effect. On the contrary, in Study B, HR significantly increased during licking in lying performers (+2.5 bpm). This reaction was even stronger, when licking was directed to the receivers' head (+3.5 bpm) or neck (+3.0 bpm) as compared to the rest of the body (+1.4 bpm). The licking category had no effect on HR changes during the licking events. Our findings suggest that relaxation effects induced by social licking differ between performers and receivers and are affected by the cows' basic activity. In receivers, there were clear indications of a calming effect implying the experience of positive affective states. In performers, such calming effects during social licking were not identified.
|
|
|
de Waal, F. B. M. (2003). Animal communication: panel discussion. Ann N Y Acad Sci, 1000, 79–87.
|
|