Effects of effort on response rate

Pigeons were trained to peck for food reinforcement, and the minimum effective force for a peck was varied. In a single-key situation, the response rate was unaffected up to a certain force value, beyond which increments caused a proportional decrement in response rate. Transient enhancement and suppression effects were observed following a change in the force requirement. A change from a high force requirement to a low force requirement resulted in a temporary enhancement of response rate above the stable performance level, whereas a change from a low to a high requirement produced a temporary suppression of the rate below the stable rate. In a two-key situation, the response rate on a key with a given force remained unaffected by the force requirement on the other key. When the rate of response was plotted against the required force, the resultant function was remarkably similar to that obtained from the single-key experiment. When the rates of reinforcement on the two keys differed, the decrement in response rate produced by an increase in the force requirement was proportionally greater on the key with the lower rate of reinforcement.     

Light source position in the perception of object shape

The apparent relief of monocularly viewed surfaces reversed when the order of light and shade was reversed relative to the position of a lamp observed the moment earlier. The pattern of shading was reversed either by illuminating from a direction opposite to that of the apparent direction of illumination or by inverting the illuminating image relative to the light source. The combination of both of these manipulations restores the original juxtaposition of light source and shading and reestablished accurate perception of relief. These results demonstrate that the perception of the relief of physical surfaces depends upon the remembered position of an apparent light source.     

A low-stress restraint procedure for EEG acquisition in awake rats

A restraint procedure was developed to reduce movement-related artifacts during the acquisition of EEG data from unanesthetized, unparalyzed rats. It combines the low-stress properties of a cloth restraint bag with the improved immobility of a rigid restraint device. The spontaneous behavior of the rat facilitates both the induction of and the subsequent release from restraint.     

The relationship between trauma and financial and physical well-being among Cambodians in the United States.

This study focused on the relationship between trauma and financial and physical well-being of Cambodian refugees in the United States. Trauma was defined by three variables: whether or not trauma had been experienced in Cambodia, the number of traumas experienced, and the number of years spent in refugee camps. It was hypothesized that these trauma variables would predict financial and physical health among Cambodians in the United States. A discriminant analysis showed significant relationships between the trauma variables and current employment status, and multiple regression analyses showed that trauma predicted income and physical health.     

Periodicity pitch perception and its upper frequency limit in cats

We have established a procedure for behavioral assessment of periodicity pitch perception in the cat. This procedure requires the training of cats to make a differential response to two different pure tones, and then testing for the transfer of learning when complex stimuli known to produce periodicity pitch sensations in humans are substituted for the pure tones. Complex stimuli consisted of three to five harmonically related frequencies of the same amplitude and phase. Eight cats were the subjects of these experiments. Two of them were controls. It is demonstrated here that cats do perceive periodicity pitch. We also used this procedure to measure the upper frequency limit of periodicity pitch perception for two cats. The frequencies tested were 100, 200, 300, 400, 600, 800, 900, and 1,200 Hz. The data indicate that the upper frequency limit of periodicity pitch perception in the cat is on the order of 600 to 800 Hz. There is a trend of decreasing prominence of the perception of periodicity pitch as the component frequencies are increased. These results are parallel to the human psychophysical data.     

Relationship between environmental factors and burnout of psychotherapists: Meta‐analytic approach

The present study aims to extend the scope of understanding on the relationships between environmental factors and burnout symptoms by targeting and including more extensive occupational demanding variables related to therapist burnout. The present study includes not only common occupational stressors (e.g., working hours, role overload and role conflict) but also variables reflecting the quality of relationship with clients (e.g., case load and negative clientele) that have not been dealt with before in meta‐analytic studies. A meta‐analysis was conducted on 27 original studies published from the year 2006 to 2018. The findings showed that, among environmental factors, role overload had the most significant positive correlations with exhaustion. In addition, negative clientele had the most significant positive correlations with depersonalisation and reduced accomplishment. Furthermore, caseload and low income had relatively weak relations with therapist burnout. Based on these results, implications and limitations of the study are discussed.     

Non‐ignorable missingness item response theory models for choice effects in examinee‐selected items

Examinee‐selected item (ESI) design, in which examinees are required to respond to a fixed number of items in a given set, always yields incomplete data (i.e., when only the selected items are answered, data are missing for the others) that are likely non‐ignorable in likelihood inference. Standard item response theory (IRT) models become infeasible when ESI data are missing not at random (MNAR). To solve this problem, the authors propose a two‐dimensional IRT model that posits one unidimensional IRT model for observed data and another for nominal selection patterns. The two latent variables are assumed to follow a bivariate normal distribution. In this study, the mirt freeware package was adopted to estimate parameters. The authors conduct an experiment to demonstrate that ESI data are often non‐ignorable and to determine how to apply the new model to the data collected. Two follow‐up simulation studies are conducted to assess the parameter recovery of the new model and the consequences for parameter estimation of ignoring MNAR data. The results of the two simulation studies indicate good parameter recovery of the new model and poor parameter recovery when non‐ignorable missing data were mistakenly treated as ignorable.     

Stress Judgment and Production in English Derivation,and Word Reading in Adult Mandarin-Speaking English Learners

For monolingual English-speaking children, judgment and production of stress in derived words, including words with phonologically neutral (e.g., -ness) and non-neutral suffixes (e.g., -ity), is important to both academic vocabulary growth and to word reading. For Mandarin-speaking adult English learners (AELs) the challenge of learning the English stress system might be complicated by cross-linguistic differences in prosodic function and features. As Mandarin-speakers become more proficient in English, patterns similar to those seen in monolingual children could emerge in which awareness and use of stress and suffix cues benefit word reading. A correlational design was used to examine the contributions of English stress in derivation with neutral and non-neutral suffixes to English word and nonword reading. Stress judgment in non-neutral derivation predicted word reading after controlling for working memory and English vocabulary; whereas stress production in neutral derivation contributed to word reading and pseudoword decoding, independent of working memory and English vocabulary. Although AELs could use stress and suffix cues for word reading, AELs were different from native English speakers in awareness of non-neutral suffix cues conditioning lexical stress placement. AELs may need to rely on lexical storage of primary stress in derivations with non-neutral suffixes.