Automatic detection of irregular vanishing and reappearing parts of objects in two interwoven sequences: A visual mismatch negativity study.

The cognitive system automatically develops predictions on the basis of regularities of event sequences and reacts to the violation of these predictions. In the visual modality, the electrophysiological signature of this process is an event-related potential component, the visual mismatch negativity (vMMN). So far, we have no data, whether the system underlying vMMN is capable of dealing with more than one event sequence simultaneously. To disclose this aspect of the capacity of the system, in a passive oddball paradigm, we presented two interwoven sequences. The stimuli were objects (diamond patterns with their diagonals), one of the sequences was presented to the left side and the other to the right side of the visual field. From time to time, two parallel lines of the diamonds disappeared (OFF event) and then reappeared (ON event). The frequently vanishing pair of lines on the left side (standard) was identical to the rarely vanishing lines of the objects on the right side (deviant) and vice versa. We found that deviant ON events elicited vMMN only for left-side deviants and deviant OFF events elicited vMMN only for right-side deviants. The standardized low resolution brain electromagnetic tomography (sLORETA) source localization showed vMMN sources both in posterior visual structures and in anterior locations, and activity was stronger in the hemisphere contralateral to the deviant event. According to the results, the system underlying vMMN is capable of dealing with two sequences, but within a sequence, it detected only one type (either OFF or ON) of deviancy.

Older Adults Automatically Detect Age of Older Adults' Photographs: A Visual Mismatch Negativity Study.

The human face is one of the most frequently used stimuli in vMMN (visual mismatch negativity) research. Previous studies showed that vMMN is sensitive to facial emotions and gender, but investigations of age-related vMMN differences are relatively rare. The aim of this study was to investigate whether the models' age in photographs were automatically detected, even if the photographs were not parts of the ongoing task. Furthermore, we investigated age-related differences, and the possibility of different sensitivity to photographs of participants' own versus different ages. We recorded event-related potentials (ERPs) to faces of young and old models in younger (N = 20; 18-30 years) and older groups (N = 20; 60-75 years). The faces appeared around the location of the field of a tracking task. In sequences the young or the old faces were either frequent (standards) or infrequent (deviants). According to the results, a regular sequence of models' age is automatically registered, and faces violating the models' age elicited the vMMN component. However, in this study vMMN emerged only in the older group to same-age deviants. This finding is explained by the less effective inhibition of irrelevant stimuli in the elderly, and corresponds to own-age bias effect of recognition studies.

Behavioral and Neurophysiological Correlates of Dogs' Individual Sensitivities to Being Observed by Their Owners While Performing a Repetitive Fetching Task.

Ample evidence suggests that dogs possess enhanced skills in reading human visual attention, but it remains to be explored whether they are sensitive to the audience effect in their interactions with humans. The present study aimed to investigate how dogs' behavior is affected by their owners' visual attention while performing a repetitive task (bringing an object back to an unfamiliar experimenter while the owner waited passively). We assumed that if dogs are susceptible to the audience effect, their task persistence and task performance would vary according to their owners' attentiveness. A group of adult pet dogs (N = 27) were repeatedly presented with an object retrieval task by the experimenter (N = 20 trials) while owners either ignored their dogs (Inattentive Owner condition) or paid attention to their dogs' actions (Attentive Owner condition). Behavioral observations were complemented with the owner's reports of their relationships with their dogs (assessed by means of an owner-pet attachment questionnaire) and dogs' spectral EEG sleep profile (recorded during 3-h-long daytime sleep). Although dogs, independently of their owners' attentional state, were generally willing to comply with the fetching task, they were faster to approach the toy object and gazed significantly longer at their owners when he/she was paying attention. This finding is reminiscent of peer influence observed in humans. Further, characteristics of relationship insecurity (relationship anxiety and avoidance) were associated with dogs' task persistence and performance. Dogs of owners with higher relationship anxiety tended to approach the toy object less frequently, and dogs of owners with higher relationship avoidance and anxiety were more hesitant to approach the toy object. We also found that dogs' individual susceptibilities to the audience effect is related to EEG spectral power of both REM and non-REM sleep as well as in pre-sleep (drowsiness) in a trait-like manner. These results, in line with previous findings, support the notion that dogs have a somewhat human-like susceptibility to the audience effect, a trait which might be linked to more complex mechanisms, such as self-presentation or reputation management, helping the two species to become effective social partners.