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.     

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.     

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.     

No evidence for a cue mismatch in negative priming

An experiment is reported in which the cue mismatch hypothesis of negative priming, an important novel variant of the mismatching hypothesis, was tested. A cue mismatch and a no mismatch condition were contrasted in a visual discrimination task. In the prime display of cue mismatch ignored-repetition trials, the colour of the prime distractor was different from the colour of the cue indicating the selection feature (coloured square). In probe displays, cue and repeated stimulus had the same colour. In the no mismatch condition, the visual cue was neutral in terms of colour (always black), so that there was always no cue mismatch between prime and probe displays. Contrary to the prediction of the cue mismatch hypothesis, the negative priming effect was not larger in the cue mismatch than in the no mismatch condition. The cue mismatch hypothesis must therefore be rejected. In contrast, the episodic retrieval account is consistent with the results.     

No evidence for overgeneral memories in borderline personality disorder

The hypothesis that borderline personality disorder (BPD) is related to overgeneral memories was tested in a mixed sample of 39 patients. A memory test with emotional cue words and the instruction to produce specific autobiographical memories was used. Specificity was judged by an independent rater. Regression analyses indicated that age and major depressive disorder were related to the production of less specific memories, whereas educational level and presence of personality disorder were positivily related to number of specific memories. Borderline personality disorder, anxiety disorders and childhood traumas were not related to number of specific memories.     

No evidence for directional biases in inhibition of return

The phenomenon of “inhibition of return” (IOR) has been the subject of considerable research interest for nearly 30 years. Two reports claiming directional biases in IOR (Spalek & Hammad, Perception & Psychophysics 66:219–233, 2004, Psychological Science 16:15–18, 2005) were examined more closely, as such findings challenge the theoretical role attributed to IOR and imply that this purported mechanism for the facilitation of visual search would bias search in systematic ways. The data from two new experiments, as well as reanalysis of the original data, showed the reports to result from an unconventional method of calculating IOR that confounded visual field with target location. Although we found significant differences in target detection response times between the visual fields, directional biases were absent from all of the examined data when the conventional method of computing IOR was applied.     

No evidence for rule-based processing in the inverse base-rate effect

The inverse base-rate effect in categorization (Medin & Edelson, 1988) arises when participants assign an ambiguous stimulus to a category that occurred less frequently than an alternative category, against the principles of Bayesian decision making. In the experiment reported in this article, rule-based and attention-shifting accounts of the inverse base-rate effect were evaluated. Participants completed a categorization task, known to produce the inverse base-rate effect, under standard conditions, under time pressure, and with a secondary task load. The inverse base-rate effect persisted under severe time pressure and under secondary task load. The results provided no evidence for the role of rule-based processes in producing the inverse base-rate effect. The data from the experiment are compatible with an attention-shifting account.     

Object permanence in lemurs

Object permanence, the ability to mentally represent objects that have disappeared from view, should be advantageous to animals in their interaction with the natural world. The objective of this study was to examine whether lemurs possess object permanence. Thirteen adult subjects representing four species of diurnal lemur (Eulemur fulvus rufus, Eulemur mongoz, Lemur catta and Hapalemur griseus) were presented with seven standard Piagetian visible and invisible object displacement tests, plus one single visible test where the subject had to wait predetermined times before allowed to search, and two invisible tests where each hiding place was made visually unique. In all visible tests lemurs were able to find an object that had been in clear view before being hidden. However, when lemurs were not allowed to search for up to 25-s, performance declined with increasing time-delay. Subjects did not outperform chance on any invisible displacements regardless of whether hiding places were visually uniform or unique, therefore the upper limit of object permanence observed was Stage 5b. Lemur species in this study eat stationary foods and are not subject to stalking predators, thus Stage 5 object permanence is probably sufficient to solve most problems encountered in the wild.     

The contagious impact of playing violent video games on aggression: Longitudinal evidence

Meta-analyses have shown that violent video game play increases aggression in the player. The present research suggests that violent video game play also affects individuals with whom the player is connected. A longitudinal study (N = 980) asked participants to report on their amount of violent video game play and level of aggression as well as how they perceive their friends and examined the association between the participant's aggression and their friends’ amount of violent video game play. As hypothesized, friends’ amount of violent video game play at Time 1 was associated with the participant's aggression at Time 2 even when controlling for the impact of the participant's aggression at Time 1. Mediation analyses showed that friends’ aggression at Time 1 accounted for the impact of friends’ amount of violent video game play at Time 1 on the participant's aggression at Time 2. These findings suggest that increased aggression in video game players has an impact on the player's social network.     

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...     

Testing QuickEst: No evidence for the Quick-Estimation heuristic

The Quick-Estimation heuristic (QuickEst) was introduced by Hertwig, Hoffrage, and Martignon (1999 Hertwig , R. , Hoffrage , U. , & Martignon , L. (1999) . Quick estimation: Letting the environment do the work . In G. Gigerenzer , P. M. Todd , & the ABC Research Group (Eds.) , Simple heuristics that make us smart (pp. 209 – 234) . New York : Oxford University Press . [Google Scholar]) as a fast and frugal method to generate numerical estimates. The heuristic posits that estimate-relevant knowledge is organised and searched according to ordered reference classes that are based on binary cue values. Two experiments tested two main predictions derived from QuickEst with respect to the memory search and estimation behaviour of human participants. The results provided no evidence that QuickEst is used in numerical estimation processes. As alternative explanation of our findings, we discuss a cyclic sampling mechanism that retrieves information from memory according to their associative strength.     

No evidence for relationship between biorhythms and industrial accidents

According to the popular biorhythm model accidents are more likely to occur during the "critical days" of three sine wave-like cycles that display periodicities of 23 days, 28 days, and 33 days. Analyses of 400 mining accidents from two separate industries demonstrated that the number of employees who were involved with accidents on their individual critical days of the different cycles did not differ significantly from chance expectancy. Furthermore the number of employees involved in accidents when their cycles were in ascending phases (presumably associated with positive behaviors) did not differ significantly from the number of employees who were involved in accidents when their cycles were in the descending phases, presumably associated with negative behaviors. We have found neither empirical nor theoretical support for the biorhythm model.     

No evidence for reduced Simon cost in elderly bilinguals and bidialectals

We explored whether a bilingual advantage in executive control is associated with differences in cultural and ethnic background associated with the bilinguals' immigrant status, and whether dialect use in monolinguals can also incur such an advantage. Performance on the Simon task in older non-immigrant (Gaelic-English) and immigrant (Bengali, Gujarati, Hindi, Malay, Punjabi, Urdu-English) bilinguals was compared with three groups of older monolingual English speakers, who were either monodialectal users of the same English variety as the bilinguals or were bidialectal users of a local variety of Scots. Results showed no group differences in overall reaction times as well as in the Simon effect thus providing no evidence that an executive control advantage is related to differences in cultural and ethnic background as was found for immigrant compared to non-immigrant bilinguals, nor that executive control may be improved by use of dialect. We suggest the role of interactional contexts and bilingual literacy as potential explanations for inconsistent findings of a bilingual advantage in executive control.     

Analog number representations in mongoose lemurs (Eulemur mongoz): evidence from a search task

A wealth of data demonstrating that monkeys and apes represent number have been interpreted as suggesting that sensitivity to number emerged early in primate evolution, if not before. Here we examine the numerical capacities of the mongoose lemur (Eulemur mongoz), a member of the prosimian suborder of primates that split from the common ancestor of monkeys, apes and humans approximately 47–54 million years ago. Subjects observed as an experimenter sequentially placed grapes into an opaque bucket. On half of the trials the experimenter placed a subset of the grapes into a false bottom such that they were inaccessible to the lemur. The critical question was whether lemurs would spend more time searching the bucket when food should have remained in the bucket, compared to when they had retrieved all of the food. We found that the amount of time lemurs spent searching was indicative of whether grapes should have remained in the bucket, and furthermore that lemur search time reliably differentiated numerosities that differed by a 1:2 ratio, but not those that differed by a 2:3 or 3:4 ratio. Finally, two control conditions determined that lemurs represented the number of food items, and neither the odor of the grapes, nor the amount of grape (e.g., area) in the bucket. These results suggest that mongoose lemurs have numerical representations that are modulated by Webers Law.     

No experimental evidence for emotion-specific gaze cueing in a threat context

We examined the utility of a gaze cueing paradigm to examine sensitivity to differences among negatively valenced expressions. Participants judged target stimuli (dangerous or safe), the location of which was cued by the gaze direction of a central face. Dawel et al. reported that gaze cueing effects (faster response times on valid vs. invalid trials) were larger when the central face displayed fear than when it displayed happiness. Our aim was to determine whether this effect was specific to fear, to all threat-related expressions (fear, anger), or to all negatively valenced expressions (fear, anger, sadness, disgust) with the aim of using this protocol to study the development of implicit discrimination of negatively valenced expressions. Across five experiments in which we varied the number of models (1 vs. 4), the number of expressions (2 vs. 5), and the country of residence of participants (Canada vs. Australia) we found no evidence that the magnitude of gaze cueing effects is modulated by expression. We discuss our failure to replicate in the context of the broader literature.     

No evidence of other-race effect for Chinese faces in Malaysian non-Chinese population

The other-race effect (ORE) reflects poor recognition of faces of a different race to one's own. According to the expertise-individuation hypothesis, this phenomenon is a consequence of limited experience with other-race faces. Thus, similar experience with own and other-race faces should abolish the ORE. This study explores the ORE in a multi-racial country (i.e., Malaysia) by comparing Malaysian observers' face recognition for faces of a predominant racial group in Malaysia (i.e., Chinese) with faces from an uncommon group (i.e., Caucasian). Malaysian Chinese, Malays, and Malaysian Indians completed the Cambridge Face Memory Test (CFMT) and the CFMT-Chinese. Compared with the normative scores, Malaysian observers showed poor performance in the CFMT-Caucasian. Interestingly, Malays and Malaysian Indians observers' performance was identical to that of Malaysian Chinese in the CFMT-Chinese and to the normative scores of the test. These results demonstrate the relevance of experience in shaping the ORE.     

No evidence for a role of reconsolidation in updating of paired associates

Reconsolidation theory states that memories are labilized through reactivation, making them prone to change, before being re-consolidated. When information in memory requires updating, reconsolidation theory therefore predicts that reminders of previously learned information should facilitate updating of that information and should thus improve memory for the updated information. In two experiments, we tested this prediction by investigating memory for word pairs over a short time-scale. Participants studied word pairs (A–B), some of which were subsequently updated with word pairs that shared the first word (A–C). Half of the A–C pairs received a pre-study reminder of the first word in the pair so as to reactivate and labilize A–B memory. In a recognition memory test targeting the A–C list, reminders by and large had no effect on memory. Results thus failed to support the predictions of reconsolidation theory.