Differentiation of brain damage among low IQ subjects with three projective techniques.

Using a battery of three projective techniques (Rorschach, Hand Test, Bender-Gestalt) only slight discrimination was found between low IQ subjects classified according to the presence or absence of brain trauma (exogenous vs endogenous), while substantial discrimination was obtained between the same subjects categorized in terms of "lower" (60-74) and "higher" (75-89) FS WAIS IQ. All four groups used in this study had been first equated on sex and age. Results were interpreted as supporting the position that some sort of brain impairment underlies most or all retardation. Question was raised concerning the efficacy of projective techniques for diagnosing organicity in subjects of average or better intelligence.     

Intrinsic feedback, interpolation, and the closed-loop theory

The amount of experience of a target location, or its surrounding locations, was manipulated to test Adams' (1971) prediction that the perceptual trace (stored perception of the correct response) is based on repeated sensations of the correct response. Sixteen learning trials, each followed by knowledge of results, on a linear-positioning task were permitted for all subjects. Each learning trial required movement to an adjustable physical stop. In learning condition without target experience, movements never terminated in a zone within which the target was interpolated. Other groups experienced movements terminating at the target point. The strength of the perceptual trace was inferred from the ability to move to the target during 20 test trials with the stop removed and without knowledge of the results. Slow movements could be made to a novel location equally as well as to a repeatedly practiced location.     

On problems of context and attribution in verbal reasoning

Investigated the effect of the verb on inferences in reasoning tasks with conditionals. Subjects were 60 pupils, both male and female, aged 17 to 18 years. Six verbs (buy, have, understand, ignore, hate, avoid) served as independent variables in conditional tasks consisting of two premises. The results which are statistically, highly significant, show an effect due to the verb depending upon the logical form of the task (2Î = 86.1, df= 30). indicate that certain semantic characteristics implicit in verbs determine the way in which a reasoning task is interpreted. A second experiment investigated why verbs differ in this way. Interviews were carried out with subjects using the verbs ‘buy’ and ‘ignore’. It is suggested that implicit meanings acquired through processes of social attribution play an essential role in verbal reasoning. In the present case, such attributions concern the depositional and episodic character of verbs and appear to be responsible for the interpretation of the premises of our tasks. It is concluded that any logical model aiming at an adequate representation of language in reasoning must take these implicit social attributions into account.     

A general parametric model of similarity and subjective difference

The field of multidimensional scaling is dominated by models that lack inherent parameters. Correcting parameters have been introduced, e.g. INDSCAL, to increase power of prediction. Although a nonparametirc model with correcting parameters may exhibit a very good fit to data, a parametric model is intrinsically superior. The general parametric model proposed here yields measures of both absolute and relative subjective differences (dissimilarity) in addition to similarity. It is basically unidimensioanal. Rules for combining values of attributes into a single multidimensional value may be applied either to the input or to the output of the model. One of the resulting functions is a generalization of the Eisler-Ekman similarity function. A special case of another function is identical to the Minkowski class of distance functions (including INDSCAL). The model is not limited to pairwise relations. It yields unitary measures for any number of objects.     

A method for simulating non-normal distributions

A method of introducing a controlled degree of skew and kurtosis for Monte Carlo studies was derived. The form of such a transformation on normal deviates [X N(0, 1)] isY =a +bX +cX ² +dX ³. Analytic and empirical validation of the method is demonstrated.This work was done while the author was at the University of Illinois at Champaign-Urbana.     

Conditioned fear and startle magnitude: effects of different footshock or backshock intensities used in training

In Experiment 1 four groups of rats received 30 light-shock pairings using footshock intensities of either .2, .4, .8, or 1.6 mA. One day later all rats were tested for startle by presenting tones in the presence or absence of the light CS. Potentiated startle (the difference between startle on light-tone vs tone-alone trials) was nonmonotonically related to the shock intensity used in training, with the greatest potentiation at intermediate shock levels. Experiment 3 demonstrated a similar relationship when backshocks instead of footshocks were used. In Experiment 2 rats were trained with either a moderate or high shock and then given an extended extinction-test session 1 day later. The moderate-shock group showed a gradual decline in potentiated startle over extinction. The high-shock group showed a nonmonotonic extinction curve where potentiation progressively increased toward the middle of extinction and dissipated thereafter. The results suggest that acoustic startle bears an inverted U-shaped relationship to fear and are discussed in relation to other studies concerned with this issue.     

A wood-gnawing sensor for recording collateral behavior emitted by rats on differential reinforcement of low rate schedules

The difficulties in measuring the idiosyncratic collateral behavior emitted by rats on a DRL schedule are overcome by providing woodblocks attached to a sensor. Wood gnawing is recorded by stylus transducer signals. An audio amplifier raises these signals to a suitable level for the operation of a threshold control unit. A pulse former operates the final relay amplifier for 150 msec from the onset of disturbance to the transducer.