Biology of elderly suicide.

Most studies of suicide in younger patients have demonstrated significant alterations in the serotonin system. Although a high percentage of completed suicides occur in late-life, to date very few studies of the biology of suicide have focused on this age group. This chapter describes age-related changes in the central nervous system pertinent to the biology of suicide, then reviews post-mortem biological studies of the brains of suicides and suicide attempters. As suicide attempts in the elderly are characterized by the use of violent means, biologic studies of impulsive violence are discussed. Finally we describe data on the effect of degenerative diseases on the serotonin system and the possible link to increased suicidal behavior in affected patients. This review underscores the need for further study of the biology of suicide in the geriatric age group.     

Assessing potential reinforcement-like effects of brief stimuli unrelated to food reinforcers

It is widely assumed that reinforcers are biologically relevant stimuli, or stimuli that have been associated with biologically relevant stimuli. However, brief, arbitrary stimuli have also been reported to have reinforcement-like effects, despite being unrelated to biologically relevant stimuli like food. The present study explored the potential reinforcement-like effects of brief stimuli across 5 experiments. In Experiments 1 through 4, pigeon subjects responded for food reinforcement and brief stimulus presentations in a 2-component multiple schedule. Neither baseline response rates nor resistance to change during disruption tests were systematically greater in a component with versus without brief stimulus presentations. Increasing the rate and duration of brief stimulus presentations in Experiment 4 did not reveal reinforcement-like effects when compared directly with food. In Experiment 5, pigeons chose between independent terminal links in a concurrent-chains procedure. Across conditions, varying the location, duration, and rate of brief stimulus presentations in the terminal links had no systematic effects on preference. In contrast, varying rates of food reinforcers resulted in large and reliable shifts in preference. Therefore, the present study found no systematic evidence that brief stimuli unrelated to food reliably increase response rates, resistance to change, or preference. These data demonstrate the value of systematic replication, and a behavioral momentum approach to assessing potential reinforcement-like effects.     

Adolescents' Contributions to Family Communication Patterns

Early explications of family communication patterns (FCP) suggested that a family's communication pattern arises as a result of interactions in which parents and adolescents influence each other. In contrast, empirical research usually treats FCP as parent‐imposed norms that influence socialization outcomes in adolescents, without testing whether adolescents' socialization influences FCP. This study revisits the assumption that adolescents influence FCP, using data from a longitudinal quasi‐experimental evaluation of a school‐based civics curriculum intervention (N = 313 parent‐adolescent pairs). Results show that the intervention‐stimulated adolescents to initiate discussion of politics at home and that these adolescent‐initiated discussions influenced adolescents' and parents' perceptions of FCP 6 months later.     

Differential effects of prime-probe duration on positive and negative location priming: Evidence for opponent facilitatory and inhibitory influences in priming tasks

A series of four spatial localization experiments is reported that examined the effects of display duration and presentation mode on positive and negative priming using an attended-repetition and an ignored-repetition paradigm, respectively. Experiment 1 showed larger positive priming with response-dependent than with 150 ms display durations while negative priming remained unaffected. Experiments 2-4 were performed to further elucidate the effects of prime-probe durations. Data suggest largely independent effects of prime and probe duration on priming effects. Manipulation of prime duration affected facilitation due to repetition of the prime distractor location as well as inhibitory effects associated with ignored repetition. Furthermore, anticipated probe duration modulated the effectiveness of inhibition of return. Findings are discussed within a framework proposing two major components of priming effects—a stimulus-driven or automatic component, and a strategic component related to the participant's expectations towards the probe.     

The Structure of Creativity in Primary Education: An Empirical Confirmation of the Amusement Park Theory

In this study, we explored the structure of pupils’ creativity in primary education following the Amusement Park Theory, by investigating undiscovered linkages between the domains of writing, mathematics, and drawing. More specifically, we examined: (a) whether some domains and general thematic areas are more closely related to each other than to others, (b) whether literacy and mathematical ability are specific underlying traits of creativity in writing and mathematics, respectively, and (c) whether intelligence and divergent thinking are related to creativity in all domains. The sample consisted of 331 Dutch 4th grade pupils. For each research question, a model was analyzed using structural equation modeling. We found creativity in mathematics and creativity in writing to be most similar, followed by creativity in mathematics and creativity in drawing, with creativity in writing and creativity in drawing being least similar. Additionally, we found evidence for several underlying traits (i.e., literacy ability and mathematical ability) and initial requirements of creativity (i.e., intelligence and divergent thinking), none of which were important for creativity in only one domain, and of which only intelligence was important for creativity in all domains. Herewith, our study provides insights regarding the complexity of the structure of creativity in primary education.     

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.