Antipredator behavior of newts (Cynops pyrrhogaster) against snakes

Newts and salamanders show remarkable diversity in antipredator behavior, developed to enhance their chemical defenses and/or aposematism. The present study reports on the antipredator behavior of newts (Cynops pyrrhogaster) in response to snakes. Newts displayed a significant amount of tail-wagging and tail-undulation in response to a contact stimulus from the snake’s tongue, which is a snake-specific predator stimulus, as compared to a control stimulus (behavioral scores: tongue, 1.05 ± 0.41; control, 0.15 ± 0.15). Newts that were kept in warm temperature conditions, 20°C (at which snakes are active in nature), performed tail displays more frequently than newts kept in low-temperature conditions, 4°C (at which snakes are inactive in nature). Our results suggest that the tail displays of C. pyrrhogaster could function as an antipredator defense; they direct a snake’s attention to its tail to prevent the snake from attacking more vulnerable body parts. We also discussed the reason for inter-populational variation in the tendency of newts to perform tail displays.

Stories Collectively Engage Listeners’ Brains: Enhanced Intersubject Correlations during Reception of Personal Narratives

Audiences’ engagement with mediated messages lies at the center of media effects research. However, the neurocognitive components underlying audience engagement remain unclear. A neuroimaging study was conducted to determine whether personal narratives engage the brains of audience members more than non-narrative messages and to investigate the brain regions that facilitate this effect. Intersubject correlations of brain activity during message exposure showed that listening to personal narratives elicited strong audience engagement as evidenced by robust correlations across participants’ frontal and parietal lobes compared to a nonpersonal control text and a reversed language control stimulus. Thus, personal narratives were received and processed more consistently and reliably within specific brain regions. The findings contribute toward a biologically informed explanation for how personal narratives engage audiences to convey information.

Hot Wind to the Body Can Facilitate Vection Only When Participants Walk Through a Fire Corridor Virtually

Vection has been reported to be enhanced by wind, as long as the wind is a normal temperature and not hot. However, here we report that a hot wind can facilitate vection, as long as it is natural and consistent with the visual stimulus. We created a fire-corridor stimulus that was consistent with a hot wind and a control stimulus composed of cubes, which were irrelevant to a hot wind. We compared the vection strength induced by a fire-corridor (fire condition) visual stimulus with that induced by geometric cubes (no-fire condition) visual stimulus. There were three wind type conditions: a normal temperature wind, hot wind, and no wind. The results showed that a normal temperature wind facilitated vection and that a hot wind (but not a normal wind) highly enhanced vection when a fire-corridor stimulus was presented. These results suggest that vection is highly affected and modulated by high-level cognitive processes.

Rat Ultrasonic Vocalizations as Social Reinforcers—Implications for a Multilevel Model of the Cognitive Representation of Action and Rats’ Social World

Rats are social animals. For example, rats exhibit mutual-reward preferences, preferring choice alternatives that yield a reward to themselves as well as to a conspecific, over alternatives that yield a reward only to themselves. We have recently hypothesized that such mutual-reward preferences might be the result of reinforcing properties of ultrasonic vocalizations (USVs) emitted by the conspecifics. USVs in rats serve as situation-dependent socio-affective signals with important communicative functions. To test this possibility, here, we trained rats to enter one of two compartments in a T-maze setting. Entering either compartment yielded identical food rewards as well as playback of pre-recorded USVs either in the 50-kHz range, which we expected to be appetitive or therefore a potential positive reinforcer, or in the 22-kHz range predicted to be aversive and therefore a potential negative reinforcer. In three separate experimental conditions, rats chose between compartments yielding either 50-kHz USVs versus a non-ultrasonic control stimulus (condition 1), 22-kHz USVs versus a non-ultrasonic control stimulus (condition 2), or 50-kHz versus 22-kHz USVs (condition 3). Results show that rats exhibit a transient preference for the 50-kHz USV playback over non-ultrasonic control stimuli, as well as an initial avoidance of 22-kHz USV relative to non-ultrasonic control stimuli on trend-level. As rats progressed within session through trials, and across sessions, these preferences diminished, in line with previous findings. These results support our hypothesis that USVs have transiently motivating reinforcing properties, putatively acquired through association processes, but also highlight that these motivating properties are context-dependent and modulatory, and might not act as primary reinforcers when presented in isolation. We conclude this article with a second part on a multilevel cognitive theory of rats’ action and action learning. The “cascade” approach assumes that rats’ cognitive representations of action may be multilevel. A basic physical level of action may be invested with higher levels of action that integrate emotional, motivational, and social significance. Learning in an experiment consists in the cognitive formation of multilevel action representations. Social action and interaction in particular are proposed to be cognitively modeled as multilevel. Our results have implications for understanding the structure of social cognition, and social learning, in animals and humans.

Concluding Speculations

This final chapter is speculative. It addresses the entrainment assumptions of universality and resonance by reviewing the natural environments of a range of different species, from crickets to whales. The idea is that sensitivity to both rate and rhythm across different species is support for assuming natural driving rhythms exist that facilitate entrainment in a wide range of other species. Also discussed are two artifactual environments experienced by humans: namely, that of laboratory studies that artificially control stimulus timing and the contemporary machine-driven environment of computers and iPhones. The latter are speculated to lead to a sporadic habitat based on fast irregular (artifactual) driving rhythms.

When a Reactivated Visual Mask Disrupts Serial Recall

To prevent forgetting in working memory, the attentional refreshing is supposed to increase the level of activation of memory traces by focusing attention. However, the involvement of memory traces reactivation in refreshing relies in the majority on indirect evidence. The aim of this study was to show that refreshing relies on the reactivation of memory traces by investigating how the reactivation of an irrelevant trace prevents the attentional refreshing to take place, and (2) the memory traces reactivated are sensorial in nature. We used a reactivated visual mask presented during the encoding (Experiment 1) and the refreshing (Experiment 2) of pictures in a complex span task. Results showed impaired serial recall performance in both experiments when the mask was reactivated compared to a control stimulus. Experiment 3 confirmed the refreshing account of these results. We proposed that refreshing relies on the reactivation of sensory memory traces.

Fear of self-annihilation and existential uncertainty as predictors of worldview defense: Comparing terror management and uncertainty theories

Terror management theory (TMT) proposes that thoughts of death trigger a concern about self-annihilation that motivates the defense of cultural worldviews. In contrast, uncertainty theorists propose that thoughts of death trigger feelings of uncertainty that motivate worldview defense. University students (N = 414) completed measures of the chronic fear of self-annihilation and existential uncertainty as well as the need for closure. They then evaluated either a meaning threat stimulus or a control stimulus. Consistent with TMT, participants with a high fear of self-annihilation and a high need for closure showed the greatest dislike of the meaning threat stimulus, even after controlling for their existential uncertainty. Contrary to the uncertainty perspective, fear of existential uncertainty showed no significant effects.

Disgust-Related Olfactory Processing: The Role of Gender and Trait Disgust

For the rejection of disgusting and potentially health-threatening food, the sense of smell plays a critical role. We conducted two experiments in order to investigate the role of gender and trait disgust (the temporally stable tendency to experience disgust across different situations) on disgust-related olfactory processing. A total of 40 men and women (Study 1), as well as a group of women divided according to high versus low trait disgust (Study 2, n = 59), were compared with regard to their odor thresholds for carbon disulfide (which smells like spoiled food) and a control stimulus ( n-butanol). The stimuli were rated for experienced arousal, negative valence, and familiarity. In addition, all participants underwent the “Sniffin' Sticks” battery assessing general olfactory performance. We found that women had a lower carbon disulfide threshold and rated this odorant as more unpleasant than men. Trait disgust was neither associated with the detection of the odorant signaling spoilage, nor with general olfactory function. The latter finding questions the role of this personality trait for olfactory-driven food-rejection responses, at least for normosmic individuals.

Further Evidence That Repeated Checking Leads to Reduced Memory Confidence, Vividness and Detail: New Evidence That Repeated Object Exposure Also Results in Memory Distrust

Researchers have suggested that distrust in one's memory is both a cause and a consequence of repeated checking. We investigated whether reduced clarity and confidence occurs to an equal degree with repeated object use and repeated checking. In addition, whether decreased memory confidence persists after a delay in checking or use was examined. Participants (N = 113) either repeatedly checked or repeatedly used a virtual stove or a light bulb stimulus (the control stimulus). Significant declines in memory accuracy, confidence, vividness and detail were observed for the experimental compared to the control stimulus. No significant differences in these effects between the checking and exposure conditions were found. A significant increase in state anxiety across pre-, mid- and post-test was found for both conditions. These findings provide further support for the notion that repeated checking can be self-perpetuating due to its impact on memory processes. The findings also suggest that checking is not necessary for these effects to occur as repeated use without checking also results in significant declines in memory accuracy, confidence, vividness and detail. Theoretical and clinical implications are discussed.

fMRI Investigation of Monocular Pattern Rivalry

In monocular pattern rivalry, a composite image is shown to both eyes. The patient experiences perceptual alternations in which the two stimulus components alternate in clarity or salience. We used fMRI at 3T to image brain activity while participants perceived monocular rivalry passively or indicated their percepts with a task. The stimulus patterns were left/right oblique gratings, face/house composites, or a nonrivalrous control stimulus that did not support the perception of transparency or image segmentation. All stimuli were matched for luminance, contrast, and color. Compared with the control stimulus, the cortical activation for passive viewing of grating rivalry included dorsal and ventral extrastriate cortex, superior and inferior parietal regions, and multiple sites in frontal cortex. When the BOLD signal for the object rivalry task was compared with the grating rivalry task, a similar whole-brain network was engaged, but with significantly greater activity in extrastriate regions, including V3, V3A, fusiform face area (FFA), and parahippocampal place area (PPA). In addition, for the object rivalry task, FFA activity was significantly greater during face-dominant periods whereas parahippocampal place area activity was greater during house-dominant periods. Our results demonstrate that slight stimulus changes that trigger monocular rivalry recruit a large whole-brain network, as previously identified for other forms of bistability. Moreover, the results indicate that rivalry for complex object stimuli preferentially engages extrastriate cortex. We also establish that even with natural viewing conditions, endogenous attentional fluctuations in monocular pattern rivalry will differentially drive object-category-specific cortex, similar to binocular rivalry, but without complete suppression of the nondominant image.