EFFECT OF REINFORCER MAGNITUDE ON PERFORMANCE MAINTAINED BY PROGRESSIVE‐RATIO SCHEDULES

This experiment examined the relationship between reinforcer magnitude and quantitative measures of performance on progressive‐ratio schedules. Fifteen rats were trained under a progressive‐ratio schedule in seven phases of the experiment in which the volume of a 0.6‐M sucrose solution reinforcer was varied within the range 6–300 μl. Overall response rates in successive ratios conformed to a bitonic equation derived from Killeen's (1994) Mathematical Principles of Reinforcement. The “specific activation” parameter, a, which is presumed to reflect the incentive value of the reinforcer, was a monotonically increasing function of reinforcer volume; the “response time” parameter, δ, which defines the minimum response time, increased as a function of reinforcer volume; the “currency” parameter, b, which is presumed to reflect the coupling of responses to the reinforcer, declined as a function of volume. Running response rate (response rate calculated after exclusion of the postreinforcement pause) decayed monotonically as a function of ratio size; the index of curvature of this function increased as a function of reinforcer volume. Postreinforcement pause increased as a function of ratio size. Estimates of a derived from overall response rates and postreinforcement pauses showed a modest positive correlation across conditions and between animals. Implications of the results for the quantification of reinforcer value and for the use of progressive‐ratio schedules in behavioral neuroscience are discussed.     

The contingent a priori and the publicity of a priori knowledge

Kripke maintains that one who stipulatively introduces the term ‘one meter’ as a rigid designator for the length of a certain stick s at time t is in a position to know a priori that if s exists at t then the length of s at t is one meter. Some (e.g., Soames 2003) have objected to this alleged instance of the contingent a priori on the grounds that the stipulator's knowledge would have to be based in part on substantive metalinguistic knowledge. I examine Soames's argument for the a posteriority of the relevant metalinguistic knowledge, and I argue that its main premise is false.     

Sexual Priming, Gender Stereotyping, and Likelihood to Sexually Harass: Examining the Cognitive Effects of Playing a Sexually-Explicit Video Game

The present study examines the short-term cognitive effects of playing a sexually explicit video game with female “objectification” content on male players. Seventy-four male students from a university in California, U.S. participated in a laboratory experiment. They were randomly assigned to play either a sexually-explicit game or one of two control games. Participants’ cognitive accessibility to sexual and sexually objectifying thoughts was measured in a lexical decision task. A likelihood-to-sexually-harass scale was also administered. Results show that playing a video game with the theme of female “objectification” may prime thoughts related to sex, encourage men to view women as sex objects, and lead to self-reported tendencies to behave inappropriately towards women in social situations.     

The role of the nucleus accumbens in knowing when to respond

While knowing what to expect is important, it is equally important to know when to expect it and to respond accordingly. This is apparent even in simple Pavlovian training situations in which animals learn to respond more strongly closer to reward delivery. Here we report that the nucleus accumbens core, an area well-positioned to represent information about the timing of impending rewards, plays a critical role in this timing function.     

Treatment Foster Care in a System of Care: Sequences and Correlates of Residential Placements

We examined Treatment Foster Care (TFC) in residential trajectories for youth with psychiatric disorders and aggressive behavior. We analyzed residential placements of a statewide sample of youth during the 12 months preceding and following admission to TFC. Prior to TFC, the majority of youth were residing in more restrictive settings (group homes or residential treatment). Two-thirds of youth remained in TFC throughout the follow-up year. Of those who left, nearly half returned home, and slightly fewer were discharged to group homes. By the end of the 12-month follow-up period, rates of group home use were similar to those seen in the pre-TFC period. Movement out of TFC during the year was associated with being older at placement and with increased problem behavior (particularly externalizing behaviors). TFC serves as a step-down placement for a substantial number of youth. However, this is not the only way it is used, and models based on short-term transitioning or reunification with families may not be widely implemented or relevant in practice. Additional research is needed to understand current functions of TFC in residential trajectories and to maximize its utility in systems of care.     

Reliability of self-reported service use: Test-retest consistency of children's responses to the Child and Adolescent Services Assessment (CASA)

This paper reports on the reliability of children's responses on the Child and Adolescent Services Assessment (CASA) — a self-report instrument for use with 8– to 18-year-olds that gathers information about services used to address mental health problems. Findings were based on interviews completed by 77 children at a one week test-retest interval. Results showed that reports of lifetime service use were as reliable as were reports of service use in the preceding three months. Children reported restrictive and intrusive services more reliably than services that were provided in their natural environment. Reliability appeared to be associated more strongly with characteristics of the type of service than with characteristics of the child. Children also could report reliably on some details about their encounters with service providers (e.g., length of stay, number of visits, and onset of service use).     

New polytypes of long-period stacking ordered structures in a near-equilibrium Mg97Zn1Y2 alloy

By atomic-scale high-angle annular dark-field scanning transmission electron microscopy, the long-period stacking ordered (LPSO) structures in a near-equilibrium Mg₉₇Zn₁Y₂ (at.%) alloy have been characterised. In addition to 18R and 14H, new polytypes of LPSO structures are analysed and determined as 60R, 78R, 26H, 96R, 38H, 40H, 108H and 246R. All of these LPSO structures feature AB′C′A building blocks with two Mg layers and three Mg layers sandwiched between them. The Bravais lattices and space groups of new polytypes of LPSO structures were easily determined via the newly introduced method. A structural relationship between the LPSOs is proposed.     

A Time-Varying Measure of Dyadic Synchrony for Three-Dimensional Motion

We propose a novel approach to the analysis of synchronized three-dimensional motion in dyads. Motion recorded at high time resolution, as with a gaming device, is preprocessed in each of the three spatial dimensions by spline smoothing. Synchrony is then defined, at each time point, as the cosine between the two individuals’ estimated velocity vectors. The approach is extended to allow a time lag, allowing for the analysis of leader-follower dynamics. Mean square cosine over the time range is proposed as a scalar summary of dyadic synchrony, and this measure is found to be positively associated with cognitive empathy.     

Effect of pressure on the mechanical and dynamical stability of NaAlSi

The effects of pressure on the mechanical and dynamical stability of NaAlSi have been fully investigated by first-principles calculations within the generalised gradient approximation (GGA). The obtained results show that the optimised lattice constants, atomic positions and elastic constants at ambient pressure are in good agreement with the available experimental and theoretical data. The lattice constants decrease monotonically with increasing pressure. The elastic constant C₁₁, C₁₂, C₁₃, C₃₃ and C₆₆ increase while C₄₄ decreases with increasing pressure. It is found that NaAlSi is mechanically unstable when the pressure is above 25.97?GPa. The phonon-dispersion curves along several high symmetry lines are obtained. The phonon frequencies at the Z point decrease with increasing pressure and completely soften to zero at 27.52?GPa, further confirming the structural instability of NaAlSi.     

Withstanding the test of time: Multisensory cues improve the delayed retention of incidental learning

Multisensory tools are commonly employed within educational settings (e.g. Carter & Stephenson, 2012 ), and there is a growing body of literature advocating the benefits of presenting children with multisensory information over unisensory cues for learning (Baker & Jordan, 2015 ; Jordan & Baker, 2011 ). This is even the case when the informative cues are only arbitrarily related (Broadbent, White, Mareschal, & Kirkham, 2017 ). However, the delayed retention of learning following exposure to multisensory compared to unisensory cues has not been evaluated, and has important implications for the utility of multisensory educational tools. This study examined the retention of incidental categorical learning in 5‐, 7‐ and 9‐year‐olds (N = 181) using either unisensory or multisensory cues. Results found significantly greater retention of learning following multisensory cue exposure than with unisensory information when category knowledge was tested following a 24‐hour period of delay. No age‐related changes were found, suggesting that multisensory information can facilitate the retention of learning across this age range.