An investigation of auditory contagious yawning

Despite a widespread familiarity with the often compelling urge to yawn after perceiving someone else yawn, an understanding of the neural mechanism underlying contagious yawning remains incomplete. In the present auditory fMRI study, listeners used a 4-point scale to indicate how much they felt like yawning following the presentation of a yawn, breath, or scrambled yawn sound. Not only were yawn sounds given significantly higher ratings, a trait positively correlated with each individual’s empathy measure, but relative to control stimuli, random effects analyses revealed enhanced hemodynamic activity in the right posterior inferior frontal gyrus (pIFG) in response to hearing yawns. Moreover, pIFG activity was greatest for yawn stimuli associated with high as opposed to low yawn ratings and for control sounds associated with equally high yawn ratings. These results support a relationship between contagious yawning and empathy and provide evidence for pIFG involvement in contagious yawning. A supplemental figure for this study may be downloaded from http://cabn.psychonomic-journals.org/content/supplemental.     

No evidence for contagious yawning in lemurs

Among some haplorhine primates, including humans, relaxed yawns spread contagiously. Such contagious yawning has been linked to social bonds and empathy in some species. However, no studies have investigated contagious yawning in strepsirhines. We conducted an experimental study of contagious yawning in strepsirhines, testing ring-tailed and ruffed lemurs (n = 24) in a paradigm similar to one that has induced contagious yawning in haplorhines. First, in a control experiment, we investigated whether lemurs responded to projected video content in general (experiment 1). We showed them two videos to which we expected differential responses: one featured a terrestrial predator and the other a caretaker holding food. Next, to test for yawn contagion, we showed individual lemurs life-size video projections of groupmates and conspecific strangers yawning, and control footage of the same individuals at rest (experiment 2). Then, to examine whether a group context might enhance or allow for contagion, we exposed subjects to the same videos in a group setting (experiment 3). Lemurs produced alarm vocalizations and moved upward while viewing the predator, but not the caretaker, demonstrating that they do perceive video content meaningfully. However, lemurs did not yawn in response to yawning stimuli when tested alone, or with their groupmates. This study provides preliminary evidence that lemurs do not respond to yawning stimuli similarly to haplorhines, and suggests that this behavior may have evolved or become more exaggerated in haplorhines after the two major primate lineages split.     

Bridging a yawning chasm: EEG investigations into the debate concerning the role of the human mirror neuron system in contagious yawning

Ongoing debate in the literature concerns whether there is a link between contagious yawning and the human mirror neuron system (hMNS). One way of examining this issue is with the use of the electroencephalogram (EEG) to measure changes in mu activation during the observation of yawns. Mu oscillations are seen in the alpha bandwidth of the EEG (8–12 Hz) over sensorimotor areas. Previous work has shown that mu suppression is a useful index of hMNS activation and is sensitive to individual differences in empathy. In two experiments, we presented participants with videos of either people yawning or control stimuli. We found greater mu suppression for yawns than for controls over right motor and premotor areas, particularly for those scoring higher on traits of empathy. In a third experiment, auditory recordings of yawns were compared against electronically scrambled versions of the same yawns. We observed greater mu suppression for yawns than for the controls over right lateral premotor areas. Again, these findings were driven by those scoring highly on empathy. The results from these experiments support the notion that the hMNS is involved in contagious yawning, emphasise the link between contagious yawning and empathy, and stress the importance of good control stimuli.     

Auditory contagious yawning in domestic dogs (Canis familiaris): first evidence for social modulation

Dogs' capacity to 'catch' human yawns has recently attracted the attention of researchers in the field of animal cognition. Following recent studies suggesting that contagion yawning in humans, and some other primates, is empathy-related, some authors have considered the possibility that the same mechanism may underlie contagious yawning in dogs. To date, however, no positive evidence has been found, and more parsimonious hypotheses have been put forward. The present study explored the 'contagion-only' hypothesis by testing whether the mere sound of a human yawn can be sufficient to elicit yawning in dogs, in a way that is unaffected by social-emotional factors. Unexpectedly, results showed an interesting interplay between contagion and social effects. Not only were dogs found to catch human yawns, but they were also found to yawn more at familiar than unfamiliar yawns. Although not allowing for conclusive inferences about the mechanisms underlying contagious yawning in dogs, this study provides first data that renders plausible empathy-based, emotionally connected, contagious yawning in these animals.     

Avoidance learning facilitates temporal processing in the primary auditory cortex

The primary auditory cortex is now known to be involved in learning and memory, as well as auditory perception. For example, spectral tuning often shifts toward or to the frequency of the conditioned stimulus during associative learning. As previous research has focused on tonal frequency, less is known about how learning might alter temporal parameters of response in the auditory cortex. This study addressed the effects of learning on the fidelity of temporal processing. Adult male rats were trained to avoid shock that was signaled by an 8.0 kHz tone. A novel control group received non-contingent tone and shock with shock probability decreasing over days to match the reduced number of shocks received by the avoidance group as they mastered the task. An untrained (nai ve) group served as a baseline. Following training, neuronal responses to white noise and a broad spectrum of tones were determined across the primary auditory cortex in a terminal experiment with subjects under general anesthesia. Avoidance conditioning significantly improved the precision of spike-timing: the coefficient of variation of 1st spike latency was significantly reduced in avoidance animals compared to controls and nai ves, both for tones and for noise. Additionally, avoidance learning was accompanied by a reduction of the latency of peak response, by 2.0-2.5 ms relative to nai ves and approximately 1.0 ms relative to controls. The shock-matched controls also exhibited significantly shorter peak latency of response than nai ves, demonstrating the importance of this non-avoidance control. Plasticity of temporal processing showed no evidence of frequency specificity and developed independently of the non-temporal parameters magnitude of response, frequency tuning and neural threshold, none of which were facilitated. The facilitation of temporal processing suggests that avoidance learning may increase synaptic strength either within the auditory cortex, in the subcortical auditory system, or both.     

Rhythmic structure facilitates learning from auditory input in newborn infants

Rhythm and metrical regularities are fundamental properties of music and poetry - and all of those are used in the interaction between infants and their parents. Music and rhythm perception have been shown to support auditory and language skills. Here we compare newborn infants’ learning from a song, a nursery rhyme, and normal speech for the first time in the same study. Infants’ electrophysiological brain responses revealed that the nursery rhyme condition facilitated learning from auditory input, and thus led to successful detection of deviations. These findings suggest that coincidence of prosodic cue patterns and to-be-learned items is more important than the format of the input. Overall, the present results support the view that rhythm is likely to create a template for future events, which allows auditory system to predict prospective input and thus facilitates language development.     

Contingent auditory feedback of arm movement facilitates reaching behavior in infancy

The purpose of this study was to investigate the influence of contingent auditory feedback on the development of infant reaching. Eleven full-term infants were observed biweekly from the age of 10 weeks to 16 weeks, and their arm kinematics were recorded. Auditory feedback that was contingent on arm kinematics was provided in the form of: (a) the mother's voice; and (b) musical tones. Results showed that providing auditory feedback (mother's voice or musical tones): (i) increased the amplitude of exploratory arm movements before the onset of reaching; and (ii) increased the number of reaches at the onset of reaching. These results show that infants are able to use contingent auditory feedback to explore the relevant possibilities for action that are subsequently shaped into goal-directed movements.     

Power in mixed-sex stranger interactions

The authors tested the approach/inhibition theory of power by examining teasing interactions between women and men in conditions in which either one was given elevated power or they were in an equal-power control condition. Consistent with hypotheses, high-power individuals behaved in a disinhibited fashion and were less accurate judges of their partner's emotion, whereas low-power individuals behaved in a more inhibited, indirect fashion and reported more self-conscious/anxiety-related emotion. Additional contrast analyses revealed only modest support for the claim that men would act in powerful fashion in the absence of explicit power differences, and that power-based differences were greatest when the man had power over the woman. Discussion focuses on different perspectives on the interaction between power and gender.     

Contagious yawning in African painted dogs

Animal Cognition - Contagious yawning (CY), which is yawning elicited by sensing another yawning, has been observed only in social species and is considered linked to high sociality. Although this...     

Medial prefrontal cortex activation facilitates re-extinction of fear in rats

It has been suggested that reduced infralimbic (IL) cortical activity contributes to impairments of fear extinction. We therefore explored whether pharmacological activation of the IL would facilitate extinction under conditions it normally fails (i.e., immediate extinction). Rats received auditory fear conditioning 1 h before extinction training. Immediately prior to extinction, rats received microinfusions into the IL of the GABA(A) receptor antagonist, picrotoxin, or the NMDA receptor partial agonist, D-cycloserine. Although neither drug facilitated extinction, they both facilitated the subsequent re-extinction of fear when animals were trained in a drug-free state, suggesting that activating the IL primes behavioral extinction.     

Posttraining handling facilitates memory for auditory-cue fear conditioning in rats

A large number of studies have indicated that stress exposure or the administration of stress hormones and other neuroactive drugs immediately after a learning experience modulates the consolidation of long-term memory. However, there has been little investigation into how arousal induced by handling of the animals in order to administer these drugs affects memory. Therefore, the present study examined whether the posttraining injection or handling procedure per se affects memory of auditory-cue classical fear conditioning. Male Sprague-Dawley rats, which had been pre-handled on three days for 1 min each prior to conditioning, received three pairings of a single-frequency auditory stimulus and footshock, followed immediately by either a subcutaneous injection of a vehicle solution or brief handling without injection. A control group was placed back into their home cages without receiving any posttraining treatment. Retention was tested 24 h later in a novel chamber and suppression of ongoing motor behavior during a 10-s presentation of the auditory-cue served as the measure of conditioned fear. Animals that received posttraining injection or handling did not differ from each other but showed significantly less stimulus-induced movement compared to the non-handled control group. These findings thus indicate that the posttraining injection or handling procedure is sufficiently arousing or stressful to facilitate memory consolidation of auditory-cue classical fear conditioning.     

Grooming and yawning trace adjustment to unfamiliar environments in laboratory Sprague-Dawley rats (Rattus norvegicus)

The authors studied grooming and yawning caused by mild stress in laboratory Sprague-Dawley rats (Rattus norvegicus). Two groups received 3 and 6 sequences of 5 foot shocks at random intervals (RI) and fixed intervals (FI), respectively. A 3rd group was not shocked (NS). The groups were exposed for 60 min twice. Grooming did not differ among groups, but yawning diminished with RI. Yawning increased and grooming decreased with the 2nd exposure, except in RI in which grooming increased. In NS and FI, grooming prevailed during the first 20 and 30 min, respectively, whereas yawning dominated the remainder of the time. In RI, grooming occurred more than yawning. An upward shift on this scale causes grooming to substitute yawning, whereas a downward shift causes the reverse effect.     

Discrimination of auditory intensities by rats

Rats were trained to press one of two keys when a standard intensity value of a 4.0-kHz sine tone (70 or 100 db re 2 x 10(-4) microbar) was presented from a centrally located loudspeaker. Pressing the other key was reinforced when comparison intensity values (as much as 30 db less than the standard value) were presented. The animals initiated tone presentations by breaking a light beam at the rear of the chamber. Correct choices produced brain-stimulation reinforcement, and errors produced a timeout. A procedure designed by Jenkins was used to partial out choice data under potential control of sequential cues in the stimulus series. When the standard-comparison intensity difference was varied, the rats showed similar psychometric functions despite wide differences in response bias (relative position preference). A signal detection analysis showed that response biases for individual animals remained fairly consistent during psychophysical testing. The trend of decreasing choice accuracy at small intensity differences was described by the cumulative normal probability function. The similarity of psychometric functions obtained with 70- and 100-db standards supported Weber's law. There was some evidence that response latencies were controlled by intensity differences even when choice behavior was undifferentiated.     

Enhanced prenatal auditory experience facilitates species-specific visual responsiveness in bobwhite quail chicks (Colinus virginianus)

Premature stimulation of a later developing sensory system is known to impact the functioning of earlier developing sensory systems. For example, exposure to premature (prenatal) visual experience results in a decline in species-typical auditory responsiveness in several precocial bird species. The present study examined the influence of experiential enhancement of an earlier developing sensory system on a later developing modality. Specifically, the influence of enhanced prenatal auditory stimulation on subsequent postnatal auditory and visual functioning of bobwhite quail (Colinus virginianus) chicks was assessed. Results indicate that birds receiving exposure to increased amounts of unaltered, species-typical embryonic vocalizations before hatching show species-typical auditory responsiveness at both 12 hr and 24 hr after hatching, but exhibit an accelerated pattern of species-typical visual responsiveness by 24 hr of age. These findings suggest that enhancement of an earlier developing sensory system can facilitate the development of a later developing sensory system and serve to demonstrate the dynamic nature of early perceptual organization.     

Agmatine facilitates memory of an inhibitory avoidance task in adult rats

Agmatine is a new putative neurotransmitter; however, the physiological role(s) of this endogenous released polyamine is still to be determined. We investigated its cognitive effect in an inhibitory avoidance task in adult rats. Agmatine (0.1, 1, 10, and 20 mg/kg) or saline was administered ip immediately after training or 1 h before testing. Posttraining injection of agmatine facilitated (p < 0.05) memory consolidation in this task; however pretest treatment showed no effect on retrieval (p > 0.05). We suggest that the facilitatory effect of agmatine on memory consolidation in inhibitory avoidance task might be mediated through the activation of the locus coeruleus.     

Statistical modelling in the investigation of stranger rape

A sample of stranger rape offences (n = 271) registered in the Dutch Violence Crime Linkage Analysis System database in the Netherlands between 1997 and 2007 was studied with the objective of developing statistical models, which give an indication of the probability of basic offender characteristics. Observable crime characteristics concerning the modus operandi, interaction between the offender and the victim, violence, precautionary measures, and sexual behaviours were selected in the dataset. Offender characteristics were selected based on their usefulness for the police organisation in narrowing the scope of a criminal investigation. Spatial behaviour, criminal history, and living situation of the offender were selected. From the predictive models, four out of five achieved a correct rate of over 70%, and all models predicted better than the best guess method. The proposed models for distance and prior convictions for violence seem particularly promising. Both these models show an improvement of correctly predicted offender characteristics of more than 20 percentile points compared with that which could have been estimated based on the average in the total sample. The predictive value of the models needs to be tested further with ‘new offences’, which were not used to construct the model. In general, the current study supports the finding that crime characteristics can be used to get an indication of the probability of certain offender characteristics. Nevertheless, for an understanding of the relationship between the crime characteristics and offender characteristics, a further development of a theoretical framework is urgently necessary. Copyright © 2009 John Wiley & Sons, Ltd.     

Repeated cocaine experience facilitates sucrose-reinforced operant responding in enriched and isolated rats

The purpose of the present experiment was to determine whether repeated cocaine exposure differentially affects sucrose-reinforced operant responding in rats raised in an enriched condition (EC) or an isolated condition (IC). Specifically, the performance of EC and IC rats pressing a lever for sucrose under a high fixed-ratio schedule (FR 30) prior to and after 10 days of exposure to cocaine (15 mg/kg, i.p.) or saline was compared. Regardless of rearing condition, rats repeatedly exposed to cocaine had shorter reacquisition latencies to complete a sucrose-reinforced FR 30 task than saline controls. The results suggest that cocaine exposure may have cross-sensitized both EC and IC rats to the reinforcing effects of sucrose or sucrose-associated cues, thus facilitating reacquisition of operant responding.