A developmental study of schedule-induced polydipsia in the rat

Rats 30, 60, 90, and 120 days of age were fed 105 45-mg food pellets on a noncontingent VT 70-sec schedule during 14 daily 2-hr sessions. Every animal became polydipsic on this schedule when compared with a schedule in which 105 pellets were presented at the beginning of the session. Mean polydipsic ratios (schedule intake/control intake) ranged from 2.9–5.4. Water intakes (milliliters per 100g body weight) did not differ during the last five sessions as a function of age. The results are discussed with respect to the generality of the class of adjunctive behaviors.     

Configural-like effects observed in the course of second-order conditioning in rats

After receiving first-order CER (conditioned emotional response) conditioning, four groups of rats were exposed to the first-order conditioned stimulus (CS₁) and a new stimulus (CS₂) according to one of three paradigms. For different groups, CS₂ preceded CS₁, was simultaneously compounded with it, or was explicitly unpaired with it. There was evidence of second-order conditioning (SOC) only when CS₂ preceded CS₁, with the effect diminishing when SOC training was continued for a long time. Though suppression to CS₁ extinguished in the course of SOC training, animals which had experienced CS₂ preceding CS₁ suppressed almost completely when later tested with CS₁ alone. This “protection-from-extinction” is formally similar to an analogous effect observed in the simultaneous compound group. Animals appear to “configure” elements of both simultaneous and successive compounds.     

The perception of interleaved melodies

If the notes of two melodies whose pitch ranges do not overlap are interleaved in time so that successive tones come from the different melodies, the resulting sequence of tones is perceptually divided into groups that correspond to the two melodies. Such “melodic fission” demonstrates perceptual grouping based on pitch alone, and has been used extensively in music.Experiment I showed that the identification of interleaved pairs of familiar melodies is possible if their pitch ranges do not overlap, but difficult otherwise. A short-term recognition-memory paradigm (Expt II) showed that interleaving a “background” melody with an unfamiliar melody interferes with same-different judgments regardless of the separation of their pitch ranges, but that range separation attenuates the interference effect. When pitch ranges overlap, listeners can overcome the interference effect and recognize a familiar target melody if the target is prespecified, thereby permitting them to search actively for it (Expt III). But familiarity or prespecification of the interleaved background melody appears not to reduce its interfering effects on same-different judgments concerning unfamiliar target melodies (Expt IV).     

Summation of food and shock based responding

In a multiphase experiment, dogs first received discriminative, discretetrial, barrier-jumping training with two tones (S^D, S^Δ) in a shuttle box reinforced by either shock avoidance (Group I) or by food (Group II). Then the dogs were trained on free-operant barrier-jumping reinforced by the qualitatively opposite reinforcer—food in Group I and shock avoidance in Group II. Finally, test presentations of the tone stimuli were superimposed on the free-operant behavior. The tone S^Ds markedly facilitated responding in all animals. This experiment demonstrates a summation of responding maintained by shock avoidance and food reinforcement and casts doubt on explanations of conditioned suppression outcomes that appeal solely to incompatible motivational states within the organism.     

Isolating the components of intelligence

In a recent volume (Sternberg, 1977b), I proposed a method called componential analysis that provides a means to isolate the components of intelligent performance. The method was described in detail, and then tested in a series of experiments. But an important question was left unanswered by this early work: Is componential analysis generalizable to tasks other than analogies? More recently, I have been investigating the generalization of the methodology to other tasks, and have also been engaged in extending the methodology in order to increase its flexibility of application. The present article (a) briefly summarizes the structure of a componential analysis, (b) describes the method of precuing, the method originally used for isolating the components of intelligence, and (c) describes new methods that have also been successful in isolating these components in a variety of reasoning tasks.     

The effects of commercial interruption of violent and nonviolent films on viewers' subsequent aggression

Aggressive responses following the viewing of violent and nonviolent films were studied. Groups of subjects saw one of three full-length films: (1) a staged violent film, (2) a realistic violent film, or (3) a nonviolent film. For half of the groups of subjects, films were interrupted periodically by sets of commercials. Results confirmed predictions that aggressive responses will be greater after viewing aggressive films than nonaggressive films, and that aggressive responses will be greater if films are interrupted by commercials than when not interrupted. A hypothesis predicting an interaction such that aggressive responses will be maximal when violent films are interrupted by commercials was supported. No differences in aggressiveness following presentation of realistic and staged violent films were found.     

Effects of initial limb position on the accuracy, reaction time and electromyographic patterns of rapid movements

An experiment was performed to determine the effects of initial limb condition on final accuracy of rapid, elbow flexion movements in the horizontal plane. Electromyographic (EMG) recordings were also taken from an agonist (biceps) and antagonist (triceps) muscle by means of bipolar surface electrodes. In the experiment the subject's forearm was passively oscillated by means of an electric motor, and when an auditory buzzer sounded, the subject was required to react as quickly as possible and rapidly move to the previously learned target angle. Thus, movements could be initiated from either static or moving starting positions. The results indicated that general accuracy was not greatly affected by these manipulations, however, constant error and pre-motor reaction time suggested that subjects may have been utilizing initial limb condition information contrary to a mass-spring view. EMG data showed that the timing characteristics of the agonist and antagonist muscles were modulated, depending on the type of movement produced, supporting an impulse-timing model (Wallace 1981).