Effects of cycle length on performance on a temporally defined avoidance schedule

Three rats were trained on a temporally defined avoidance schedule logically similar to a fixed-interval, limited-hold positive reinforcement schedule. This avoidance schedule was composed of time periods during which responses had no scheduled consequences alternating with time periods during which a response precluded shock. As with fixed-interval length and response rate on positive reinforcement schedules, an inverse relationship was obtained between the length of the no-consequence interval and response rate during the no-consequence interval. An inverse relationship was also obtained between the length of the no-consequence interval and the per cent of shocks avoided. A rate increase within the no-consequence interval, similar to that typically produced by fixed-interval positive reinforcement procedures, was displayed by one of the rats where the no-consequence interval was at intermediate values and frequency of shock was relatively high. The introduction of a discriminative stimulus correlated with the avoidance interval produced typical discriminated avoidance behavior as well as alterations in temporal patterning of responses during the no-consequence interval in the two rats exposed to this procedure. These alterations in temporal patterning disappeared when the discriminative stimulus was removed. The results were consonant with those reported in the literature involving food reinforcement and fixed-interval, limited-hold schedules.     

Some deleterious consequences of the act of recollection

Two experiments investigated the impact of responding to recognition test items that do not include a correct alternative. In Experiment 1, subjects who were given exclusively incorrect response alternatives were less likely than control subjects to favor the correct alternatives on a second recognition test. Analysis of subjects’ responses indicated that commitments, rather than distractor familiarity, was the main source of this effect. In Experiment 2, an impairing effect of committing to an incorrect alternative was observed even when the initial distractors were excluded from the final test. Thus, this decreased performance cannot simply be attributed to a bias toward remaining consistent. One interpretation of these results is that committing to a distractor causes subjects to remember a false detail that can interfere with their later ability to access the original information. Other potential theoretical and applied implications of these results are explored.     

Birth order and intelligence: an immunological interpretation.

The literature indicates that the IQs and school performance of children tend to decline with increasing order of birth. A hypothesis is here presented that the effect of birth order upon intellectual performance may result from an increasing probability of maternal immune attack upon the fetal brain in utero with order of parity. In support of this hypothesis, evidence is adduced from the literature that the fetal brain is antigenic, that fetal antigens may reach the immune system of the mother, that the incidence of maternal sensitization to fetal antigens increases with parity, that antibodies may readily cross the placenta and reach the fetal brain, that antibodies can be highly teratogenic, and that certain antibodies may damage, in a lasting way, the structure, function, and learning capacity of brains in experimental animals and human infants.     

DEMAND EQUATIONS FOR QUALITATIVELY DIFFERENT FOODS UNDER FIXED‐RATIO SCHEDULES: A COMPARISON OF THREE DATA CONVERSIONS

Concurrent schedules were used to establish 6 hens' preferences for three foods. The resulting biases suggested wheat was preferred over honey‐puffed and puffed wheat, and puffed wheat was the least preferred food. The hens then responded under fixed‐ratio schedules for each food in 40‐min (excluding reinforcer time) sessions, with the response requirement doubling each session until no reinforcers were received. At the smaller ratios, the less preferred the food, the faster the hens' overall response rates (mainly as a result of shorter postreinforcement pauses) and the more reinforcers they received. The relations between the logarithms of the number of reinforcers obtained (consumption) and the response ratio (price) were well fitted by curvilinear demand functions. Wheat produced the smallest initial consumption (ln L), followed by honey‐puffed and puffed wheat, respectively. The response requirement at which the demand functions predicted maximal responding (P_max) were larger for wheat than for the other foods. Normalizing consumption and price, as suggested by Hursh and Winger (1995), moved the data for the three foods towards a single demand function; however, the P_max values were generally largest for puffed wheat. The results of normalization, as suggested by Hursh and Silberberg (2008), depended on the k value used. The parameter k is related to the range of the data, and the same k value needs to be used for all data sets that are compared. A k value of 8.0 gave significantly higher essential values (smaller α values) for puffed wheat as compared to honey‐puffed wheat and wheat, and the P_max values, in normalized standard price units, were largest for puffed wheat. Normalizing demand by converting the puffed and honey‐puffed wheat reinforcers to wheat equivalents (by applying the bias parameter from the concurrent‐schedules procedure) maintained separate demand functions for the foods. Those for wheat had the smallest rates of change in elasticity (a) and, in contrast to the other analyses, the largest P_max values. Normalizing demand in terms of concurrent‐schedule preference appears to have some advantages and to merit further investigation.     

Racial discrimination-induced anger and alcohol use among black adolescents

This study explored whether a relationship exists between anger among Black adolescents that has been provoked by racial discrimination, and alcohol consumption. Participants consisted of 134 Black adolescents from 14 to 18 years of age, residing in northeast Texas. All participants were administered a questionnaire measuring whether and the extent to which they might be dependent upon alcohol, a background information questionnaire which included questions about their drinking pattern, and a measure designed to assess the extent to which they feel angry either because they had been discriminated against or observed other Blacks being discriminated against or observed other Blacks being discriminated against in various situations. Only gender was found to be predictive of scores on the dependency scale. However gender, age, and racial discrimination anger scores were found to be predictive of the amount of alcohol consumed by the participants. Some implications for theory, research, and intervention are suggested.     

Information limits on identification of natural surfaces by apparent colour

By adaptational and other mechanisms, the visual system can compensate for moderate changes in the colour of the illumination on a scene. Although the colours of most surfaces are perceived to be constant ('colour constancy'), some are not. The effect of these residual colour changes on the ability of observers to identify surfaces by their apparent colour was determined theoretically from high-resolution hyperspectral images of natural scenes under different daylights with correlated colour temperatures 4,300 K, 6,500 K, and 25,000 K. Perceived differences between colours were estimated with an approximately uniform colour-distance measure. The information preserved under illuminant changes increased with the number of surfaces in the sample, but was limited to a relatively low asymptotic value, indicating the importance of physical factors in constraining identification by apparent colour.     

Neighborhood Violence and Psychosocial Adjustment in Low-Income Urban African American Children: Physical Symptoms as a Marker of Child Adjustment

We examined the association between neighborhood violence and three domains of psychosocial adjustment in low-income, urban African American children: internalizing, externalizing, and physical symptoms. Based on anecdotal and empirical evidence, it was hypothesized that, relative to internalizing and externalizing problems, a stronger association would emerge between physical symptoms and neighborhood violence. Mother-reported neighborhood violence was associated with child-reported physical symptoms, but not internalizing or externalizing symptoms. Child-reported neighborhood violence was associated with child-reported internalizing, externalizing, and physical symptoms; however, neighborhood violence accounted for a greater percentage of variance in physical symptoms than the other two symptom domains. Our findings were not moderated by the age or gender of the child. We discuss the importance of physical symptoms as a marker of child adjustment in low-income, urban, African American children, as well directions for future research.     

Emerging neurotechnologies for lie-detection: promises and perils

Detection of deception and confirmation of truth telling with conventional polygraphy raised a host of technical and ethical issues. Recently, newer methods of recording electromagnetic signals from the brain show promise in permitting the detection of deception or truth telling. Some are even being promoted as more accurate than conventional polygraphy. While the new technologies raise issues of personal privacy, acceptable forensic application, and other social issues, the focus of this paper is the technical limitations of the developing technology. Those limitations include the measurement validity of the new technologies, which remains largely unknown. Another set of questions pertains to the psychological paradigms used to model or constrain the target behavior. Finally, there is little standardization in the field, and the vulnerability of the techniques to countermeasures is unknown. Premature application of these technologies outside of research settings should be resisted, and the social conversation about the appropriate parameters of its civil, forensic, and security use should begin.     

A BEHAVIORAL INTERVENTION FOR IMPROVING VERBAL BEHAVIORS OF HEROIN ADDICTS IN A TREATMENT CLINIC

Positively reinforcing appropriate behaviors improved verbal behaviors of opioid-dependent patients in a buprenorphine treatment clinic. During B phases of an ABAB design, clients received stickers for engaging in appropriate verbal or nonverbal behaviors. Each sticker provided a chance of winning $25. No reinforcement was provided during the A phases. Appropriate verbal behaviors increased during reinforcement periods, and inappropriate verbal behaviors decreased.