Sexual communication and domestication may give rise to the signal complexity necessary for the emergence of language: An indication from songbird studies

For language to be a vehicle of thought, protolanguage must develop a degree of complexity that allows for the syntactic manipulation of symbol sequences. Thus, before language emerged, a process in which signals became complex must have occurred. Here, we submit a scenario describing the process in which courtship songs gained in complexity during the course of domestication of Bengalese finches. By comparing domesticated Bengalese finches with their wild strain, white-rumped munias, we found that female preferences for complex songs were coupled with domesticated relaxed environments to give rise to song complexity. Furthermore, we found that the outcomes of domestication in Bengalese finches include decreased psychological and physiological stress reactions, decreased aggressiveness, and changed plumage colors. These characteristics are consistent with “domestication syndrome,” originally proposed for mammals but now possibly applicable to birds. Our finding that domestication was a cause of signal complexity might be helpful in considering the process of signal evolution in human language.     

Temporal expectation weights visual signals over auditory signals

Temporal expectation is a process by which people use temporally structured sensory information to explicitly or implicitly predict the onset and/or the duration of future events. Because timing plays a critical role in crossmodal interactions, we investigated how temporal expectation influenced auditory–visual interaction, using an auditory–visual crossmodal congruity effect as a measure of crossmodal interaction. For auditory identification, an incongruent visual stimulus produced stronger interference when the crossmodal stimulus was presented with an expected rather than an unexpected timing. In contrast, for visual identification, an incongruent auditory stimulus produced weaker interference when the crossmodal stimulus was presented with an expected rather than an unexpected timing. The fact that temporal expectation made visual distractors more potent and visual targets less susceptible to auditory interference suggests that temporal expectation increases the perceptual weight of visual signals.     

Is there any "free" choice? Self and dissonance in two cultures

Four experiments provided support for the hypothesis that upon making a choice, individuals justify their choice in order to eliminate doubts about culturally sanctioned aspects of the self, namely, competence and efficacy in North America and positive appraisal by other people in Japan. Japanese participants justified their choice (by increasing liking for chosen items and decreasing liking for rejected items) in the standard free-choice dissonance paradigm only when self-relevant others were primed, either by questionnaires (Studies 1-3) or by incidental exposure to schematic faces (Study 4). In the absence of these social cues, Japanese participants showed no dissonance effect. In contrast, European Americans justified their choices regardless of the social-cue manipulations. Implications for cognitive dissonance theory are discussed.     

The relative importance of spatial versus temporal structure in the perception of biological motion: an event-related potential study

We investigated how the spatiotemporal structure of animations of biological motion (BM) affects brain activity. We measured event-related potentials (ERPs) during the perception of BM under four conditions: normal spatial and temporal structure; scrambled spatial and normal temporal structure; normal spatial and scrambled temporal structure; and scrambled spatial and temporal structure. As in a previous study, we identified two negative components at both occipitotemporal regions: N210 reflected general motion processing while N280 reflected the processing of BM. We analyzed the averaged ERPs in the 200-300 ms response time window and found that spatial structure had a substantial effect on the magnitude of the averaged response amplitude in both hemispheres. This finding suggests that spatial structure of point-lights elicits a stronger response in the occipitotemporal region than temporal structure for the BM perception.     

Event-related brain potential in responses to social messages via human faces

In two experiments participants were presented a sequence of facial photographs to examine effects of pleasantness of facial expressions, namely, pleasant and unpleasant, and task relevance on P300 component of event-related brain potentials in the 3-stimulus version of the oddball task. Exp. 1 showed that, although the amplitudes of P300 were the largest in response to task-relevant target stimuli and moderate in response to task-irrelevant nontargets, the Pleasantness of stimuli did not affect the amplitudes of P300 when the stimuli were task-relevant or irrelevant. Data in Exp. 2 suggested that the emotional significance rather than physical characteristics of stimuli might be responsible for generation of P300 by task-irrelevant nontargets.     

Can we talk to robots? Ten-month-old infants expected interactive humanoid robots to be talked to by persons

As technology advances, many human-like robots are being developed. Although these humanoid robots should be classified as objects, they share many properties with human beings. This raises the question of how infants classify them. Based on the looking-time paradigm used by [Legerstee, M., Barna, J., & DiAdamo, C., (2000). Precursors to the development of intention at 6 months: understanding people and their actions. Developmental Psychology, 36, 5, 627-634.], we investigated whether 10-month-old infants expected people to talk to a humanoid robot. In a familiarization period, each infant observed an actor and an interactive robot behaving like a human, a non-interactive robot remaining stationary, and a non-interactive robot behaving like a human. In subsequent test trials, the infants were shown another actor talking to the robot and to the actor. We found that infants who had previously observed the interactive robot showed no difference in looking-time between the two types of test events. Infants in the other conditions, however, looked longer at the test event where the second experimenter talked to the robot rather than where the second experimenter talked to the person. These results suggest that infants interpret the interactive robot as a communicative agent and the non-interactive robot as an object. Our findings imply that infants categorize interactive humanoid robots as a kind of human being.     

Tobacco and alcohol tax relationships with suicide in Switzerland

Previous research has shown an empirical link between tobacco and alcohol use and suicide. If tobacco and alcohol use contribute to suicidal behaviors, then policies designed to reduce the tobacco and alcohol consumption may succeed in reducing suicides as well. To test this hypothesis, correlations for suicide rates with alcohol consumption, taxes on alcohol and tobacco in Switzerland were examined using sets of time-series data from Switzerland in 1965-1994. The tax on tobacco correlated significantly negatively with male standardized suicide rate. The tax on alcohol also correlated significantly with male standardized suicide rate in an autoregressive model. On the other hand, significant relationships with female suicide rate were not found. Policies designed to reduce tobacco consumption are consistent with a benefit of reducing suicides, particularly for men in this sample.     

Rapid acceleration of the lower arm correlates with agonist EMGs during the initial phase

Fifty-eight healthy subjects made rapid elbow extensions to a target over 54 degrees. Angular acceleration was measured and surface electromyograms (EMGs) were recorded from the antagonistic muscles using monopolar rather than bipolar electrode configurations. Marked individual differences were found in the peak value of the first derivative of acceleration (dAcc/dt_Pk). The dAcc/dt_Pk correlated with both quantitative and qualitative properties of the agonist EMGs, but not with those of the antagonist EMG. The agonist EMGs, integrated until the moment of dAcc/dt_Pk, were positively correlated with dAcc/dt_Pk. The interval between EMG onset and EMG peak decreased with increasing dAcc/dt_Pk. The duration of the initial negative phase in the EMGs, which was considered to index the time required to recruit high-threshold MUs, decreased with increasing dAcc/dt_Pk. The results indicate that the ability to rapidly accelerate the lower arm varies across subjects, probably due in part to individual differences in the neural capacity to drive the agonists.     

Effects of nonconscious perception on motor response

The present study reviews the literature on the empirical evidence for the dissociation between perception and action. We first review several key studies on brain-damaged patients, such as those suffering from blindsight and visual/tactile agnosia, and on experimental findings examining pointing movements in normal people in response to a nonconsciously perceived stimulus. We then describe three experiments we conducted using simple reaction time (RT) tasks with backward masking, in which the first (weak) and second (strong) electric stimuli were consecutively presented with a 40-ms interstimulus interval (ISI). First, we compared simple RTs for three stimulus conditions: weak alone, strong alone, and double, i.e., weak plus strong (Experiment 1); then, we manipulated the intensity of the first stimulus from the threshold (T) to 1.2T and 2T, with the second stimulus at 4T (Experiment 2); finally, we tested three different ISIs (20, 40, and 60 ms) with the stimulus intensities at 1.2T and 4T for the first and second stimuli (Experiment 3). These experiments showed that simple RTs were shorter for the double condition than for the strong-alone condition, indicating that motor processes under the double condition may be triggered by sensory inputs arising from the first stimulus. Our results also showed that the first stimulus was perceived without conscious awareness. These findings suggested that motor processes may be dissociated from conscious perceptual processes and that these two processes may not take place in a series but, rather, in parallel. We discussed the likely mechanisms underlying nonconscious perception and motor response to a nonconsciously perceived stimulus.     

There’s no ball without noise: cats’ prediction of an object from noise

We used an expectancy violation procedure to ask whether cats could use a causal rule to infer the presence of an unseen object on hearing the noise it made inside a container and predict its appearance when the container was turned over. We presented cats with either an object dropping out of an opaque container or no object dropping out (turning-over phase) after producing either a rattling sound by shaking the container with the object inside, or no sound (shaking phase). The cats were then allowed to freely explore the experimental environment (exploration phase). The relation between the sound and the object matched with physical laws in half of the trials (congruent condition) and mismatched in the other half (incongruent condition). Inferring the presence of an unseen object from the noise was predicted to result in longer looking time in the incongruent condition. The prediction was supported by the cats’ behavior during the turning-over phase. The results suggest that cats used a causal-logical understanding of auditory stimuli to predict the appearance of invisible objects. The ecology of cats’ natural hunting style may favor the ability for inference on the basis of sounds.