Fourier components of moving gratings

In designing experiments in which the proximal stimulus is a moving grating (including cases in which the distal stimulus is stationary but eye movements play a significant role), one must consider the effects of the motion of the stimulus on its Fourier components in the spatiotemporal frequency domain. Some of these effects are unexpected and counterintuitive. For example, the Fourier components of a moving grating do not include its stationary (or “instantaneous”) spatial frequency. Thus there is no linear filter that can extract a stationary grating from a moving one. Several useful relations are given for analyzing such stimuli.     

A tale of two processes: On Joseph Henrich’s the secret of our success: How culture is driving human evolution,domesticating our species,and making us smarter

We situate Henrich’s book in the larger research tradition of which it is a part and show how he presents a wide array of recent psychological, physiological, and neurological data as supporting the view that two related but distinct processes have shaped human nature and made us unique: cumulative cultural evolution and culture-driven genetic evolution. We briefly sketch out several ways philosophers might fruitfully engage with this view and note some implications it may have for current philosophic debates in moral and political theory and over the nature of extended cognition. We end by noting how Henrich’s view of the source of cultural design and innovation, and the prominence of place he gives to the extended process of cultural evolution, cuts against a cluster of broad but common views about human minds, recasting putative bugs as features and indicating that many of the distinctive features of our individual minds evolved to allow them to be effective cogs in the larger, more productive cultural machine.     

Emotions,Attitudes, and Reasons

Our emotional faculties respond to successes, gains, advantages, threats, losses, obstacles, and other personally significant objects or situations, producing positive or negative evaluations of them according to their perceived import. Being an evaluative response is a feature that emotions share with paradigm attitudes (beliefs, intentions, judgments, etc.). However, recently philosophers have been reluctant to treat emotions as attitudes. The usual reasons given have to do with the automaticity of emotions and their occasional recalcitrance. In this article, I argue that these things shouldn't disqualify emotions from counting as genuine attitudes. Our emotions do bear the kind of relationship with our reasons that is characteristic of our attitudes.     

Staying Together: A Bidirectional Delay–Coupled Approach to Joint Action

To understand how individuals adapt to and anticipate each other in joint tasks, we employ a bidirectional delay–coupled dynamical system that allows for mutual adaptation and anticipation. In delay–coupled systems, anticipation is achieved when one system compares its own time‐delayed behavior, which implicitly includes past information about the other system’s behavior, with the other system’s instantaneous behavior. Applied to joint music performance, the model allows each system to adapt its behavior to the dynamics of the other. Model predictions of asynchrony between two simultaneously produced musical voices were compared with duet pianists’ behavior; each partner performed one voice while auditory feedback perturbations occurred at unpredictable times during live performance. As the model predicted, when auditory feedback from one musical voice was removed, the asynchrony changed: The pianist’s voice that was removed anticipated (preceded) the actions of their partner. When the auditory feedback returned and both musicians could hear each other, they rapidly returned to baseline levels of asynchrony. To understand how the pianists anticipated each other, their performances were fitted by the model to examine change in model parameters (coupling strength, time‐delay). When auditory feedback for one or both voices was removed, the fits showed the expected decrease in coupling strength and time‐delay between the systems. When feedback about the voice(s) returned, the coupling strength and time‐delay returned to baseline. These findings support the idea that when people perform actions together, they do so as a coupled bidirectional anticipatory system.     

Investigating Correlates of Suicide Among Male Youth: Questioning the Close Affinity Between Suicide Attempts and Deaths

This study was based on a sample of male high school students who completed National Longitudinal Adolescent Health Surveys in 1994, 1995, and 2001. We studied these students prospectively, comparing those who later died by suicide (n = 21) with those who were still living (n = 10,101). We employed chi‐square and analysis of variance tests for statistical significance between suicide decedents and living respondents. Results showed suicide decedents were more likely to have experienced the suicide loss of another family member, to have been expelled from school, to have engaged in more delinquent actions including fighting, and to have greater involvement with the criminal justice system. Although one might have expected suicide casualties to have exhibited a greater amount of suicidal thoughts, attempts, and higher incidences of suicidality among their friends, our analyses did not find that these factors were associated with actual suicides. Should these findings be replicated, this would point to a need to refine youth suicide risk assessments. Collecting life histories, as well as identifying patterns of delinquency and fighting, may serve as more potentially fruitful means for assessing genuine suicide risk than some traditional risk assessment methods.z     

Candidate Vulnerability and Exposure to Counterattitudinal Information: Evidence From Two U.S. Presidential Elections

Politically motivated selective exposure has traditionally been understood through the lens of long‐standing attitudes and beliefs, but the role of environment in shaping information exposure practices merits further consideration. Citizens might respond to the political environment in their information‐seeking behavior for numerous reasons. Citizens who believe their position is politically vulnerable have specific cognitive and affective needs that may make them uniquely attuned to counterattitudinal information. In the context of a presidential election, this means that as the defeat of a supported candidate appears more likely, attention to counterattitudinal content will increase. Data collected in the 2008 and 2012 U.S. Presidential elections support this prediction, although this relationship was observed primarily among supporters of the Republican candidate in both elections.