Peer Contagion of Depressogenic Attributional Styles Among Adolescents: A Longitudinal Study

This study examined longitudinal associations between adolescents and their friends depressive symptoms and depressogenic attributional style. Participants included 398 adolescents in grades six through eight at the outset of the study. Adolescents completed peer nominations to identify reciprocated and unreciprocated best friendships as well as measures of depressive symptoms and depressogenic attributional style at an initial time point, and again 11 months later. Results revealed that best friends reported level of depressive symptoms was prospectively associated with adolescents own depressive symptoms and with adolescents depressogenic attributional style. Moderator effects suggested that friends attributional styles were prospectively associated with adolescents own attributional styles for those involved in reciprocated friendships. Lastly, findings offered preliminary support for adolescents Time 2 depressive symptoms as a mediator of the association between friends depressive symptoms and adolescents attributional style. Findings have important implications for cognitive and interpersonal models of adolescent depression, as well as the study of peer contagion effects.     

A model of exact small-number representation

To account for the size effect in numerical comparison, three assumptions about the internal structure of the mental number line (e.g., Dehaene, 1992) have been proposed. These are magnitude coding (e.g., Zorzi & Butterworth, 1999), compressed scaling (e.g., Dehaene, 1992), and increasing variability (e.g., Gallistel & Gelman, 1992). However, there are other tasks besides numerical comparison for which there is clear evidence that the mental number line is accessed, and no size effect has been observed in these tasks. This is contrary to the predictions of these three assumptions. Moreover, all three assumptions have difficulties explaining certain symmetries in priming studies of number naming and parity judgment. We propose a neural network model that avoids these three assumptions but, instead, uses place coding, linear scaling, and constant variability on the mental number line. We train the model on naming, parity judgment, and comparison and show that the size effect appears in comparison, but not in naming or parity judgment. Moreover, no asymmetries appear in primed naming or primed parity judgment with this model, in line with empirical data. Implications of our findings are discussed. This work was supported by Grant P5/04 from the Interuniversity Attraction Poles Program—Belgian Science Policy and by a GOA grant from the Ghent University Research Council to W.F.     

Effort in isometric muscular contractions related to force level and duration

The degree of perceived force involved in squeezing a handgrip dynamometer is shown to grow as a power function of the force of isometric contraction and also as a power function of the duration of the squeeze. The exponent for force turns out to be more than twice that for duration. These two power functions are able to predict measurements of muscle endurance, i.e., of the maximum length of time that contraction of any constant level of force can be sustained.     

Duration,luminance, and the brightness exponent

The relation of brightness to duration and luminance has been studied by matching one brightness to another and also by matching numbers to brightnesses (magnitude estimation). The two methods concur in confirming certain well-known visual functions: Bloch’s law, the Broca-Sulzer effect, and the shift of the Broca-Sulzer enhancement to shorter durations when luminance increases. It is shown that the shift with luminance requires the exponent of the power function for short-flash brightness to be larger than the exponent for stimuli of longer duration. An attempt is made to analyze some of the reasons why the procedure advocated by Graham may not give comparable results.     

Matching functions between loudness and ten other continua1

Cross-modality matches have been made between loudness and ten other perceptual continua. The matching functions are all power functions. When the exponent values of the matching functions are divided by the exponent values previously determined for the various continua, the quotients predict values for the loudness exponent. A tentative consensus suggests that the loudness exponent may be about 0.64.     

ON THE NEW PSYCHOPHYSICS

A discussion of problems and methods in modern psychophysics is presented. A distinction is made between prothetic and metathetic continua, and between ratio scales, category scales and what are called confusion scales. The paper includes a survey of some scaling experiments and reports the exponents of a number of power functions describing the relation between stimulus magnitude and subjective magnitude.     

Perceived warmth and skin temperature as functions of the duration and level of thermal irradiation!

This study examined the correlations among the degree of perceived warmth. the level and duration of irradiant flux. and the thermal response of the skin. For any constant duration. perceived warmth grew as a power function of the difference between the irradiant flux of the stimulus and the flux that approximates the absolute threshold for warmth. The exponent of the power function was about 0.87 for the shortest durations (2—6 sec). but rose to 1.04 for the longest duration of exposure (12 sec). For any constant level of flux. perceived warmth changed only slightly with duration. In contrast, superficial skin temperature. and inferred temperatures of deeper layers of the skin, rose continuously and markedly with duration. Neither the change in tissue temperature. nor the rate of change of tissue temperature, nor thermal gradient correlated consistently with level of perceived warmth. The change in the difference between the temperature 0.2 mm and that 1.0 mm below the skin surface provided a fairly good but not perfect correlate to perceived warmth. The findings suggest the possibility that sensory adaptation at the site of the receptor system mediating warmth could act in such a way as nearly to offset the effect of rising skin temperature with increased duration ofstimulation.     

Physiologic and motor conditioning and generalization in children with minimal brain dysfunction

Twenty-six children diagnosed as having minimal brain dysfunctions (MBD) were compared with 26 controls in a conditinoing and generalization procedure. Skin resistance, heart rate, and muscle action potentials were monitored throughout. Success involved learning which of two tones signalled the accessibility of a penny. Whereas 92 per cent of controls reached the criterion of five successive correct responses, only 62 per cent of MBD’s did. Further, a third of the MBD’s were so maladaptive as to force procedural variations, while only a few minor irregularities occurred with the controls. Quality of performance was related to age, intelligence, and ability to discriminate and remember tones. Controls were more physiologically reactive than MBD’s, especially in skin resistance. Physiologic differentiation of the two tones was significant in both groups of children and appeared concurrently with motor differentiation. The only evidence of physiologic generalization was in the SR data of controls. The possibility that defective arousal structures, or defective coupling of arousal structures and other perceptual and motor structures, could account for the decreased physiologic reactivity, short attention spans, and poor concentration ofsome MBD’s is discussed. This research, in conformity with other laboratory studies of the brain, indicates that motivational as well as cognitive defects may be organically based.     

Apparent warmth as a function of thermal irradiation

The skin of the back was periodically exposed to a source of radiant heat. In Experiment 1, 20 Ss matched numbers to the apparent warmth aroused by various levels of irradiant flux (method of magnitude estimation). In Experiment 2, 15 Ss matched the loudness of a white noise to the apparent uwmth aroused by the same levels used in Experiment I (method of cross-modality matching). Both experiments showed that apparent warmth is related to absorbed irradiance by a power function whose exponent is approximately 0.7.