Learned helplessness in the cockroach (Periplaneta americana)

For 3 consecutive days cockroaches (Periplaneta americana) were exposed to either escapable, inescapable, or no shock in an escape task. Twenty-four hours later they were tested in a shuttlebox escape task. There were reliable differences between escapable and inescapable animals and between inescapable and control animals in both escape latencies and the number of failures to escape.     

Sleep in the dove Zenaida asiatica

Electrographic and behavioral observations were made in five adult birds of the genus Zenaida asiatica. Five different vigilance states were quantitated: (1) Active waking (Aw) was characterized by constant behavioral activity; the nuchal electromyogram was tonically active with bursts associated to movements. The electroencephalographic pattern was low voltage and high frequency. (2) Quiet waking (Qw) was characterized by diminished behavioral activity and the EEG pattern was similar to that of Aw. (3) Drowsiness (D) was characterized by behavioral calm. Frequency of cerebral activity diminished progressively, but there were short periods of desynchronization corresponding to brief awakenings. (4) Slow wave sleep (SWS); during this period there was behavioral rest and EEG pattern of continuous slow waves and the nuchal EMG was tonically reduced. Spindles of sleep were not observed. (5) Paradoxical sleep (SP), behaviorally characterized by phasic manifestations consisting of noddings originated by rapid falling down of head and bursts of rapid eye movements. EEG activity was like that of waking state. EMG activity was maintained at the same level as during SWS but sometimes it decreased lightly. Total atonie was not observed. Sleep percentages were higher when recordings were done during the nocturnal period.     

Isolation-dependent enhancement of 2-[14C]deoxyglucose uptake in the forebrain of zebra finch males

In a previous study (H. J. Bischof & K. Herrmann (1986), Behavioral Brain Research, 21, 215-221) we demonstrated that four forebrain areas of the zebra finch male are activated in situations which arouse the animal, for example when the birds are chased around the cage or when they are exposed to a female. These areas, the hyperstriatum accessorium-dorsale (HAD), a part of the medial neo-hyperstriatum (MNH), the lateral neo-hyperstriatum (LNH), and a portion of the caudal archi-neostriatum (ANC), show enhanced 2-[14C]deoxyglucose (2-DG) uptake according to the experimental situation. On the basis of these experiments, we examined whether the activation of the areas is correlated with motor activity and is influenced by different isolation times prior to a 2-DG experiment, where courtship of the male birds is elicited by exposing them to a female zebra finch. For this purpose, we isolated male zebra finches for 1 day, 1 week, or 8 weeks, respectively, before we injected the 2-DG and exposed the birds to a female. During the experiment, besides other activities, the number of song motifs performed by the bird and the frequency of changing perches was recorded. Our experiments demonstrate that there is a weak negative correlation between motor activity and 2-DG uptake, and a positive correlation between isolation time and 2-DG uptake. We suggest that long isolation blocks courtship behavior by some unknown mechanisms, and that the "internal drive" of the animal, which possibly corresponds with the activity of the four forebrain areas, is enhanced by isolation and by the fact that the birds do not perform the consummatory behavior. Our results also demonstrate that the 2-DG method can show up small differences in the internal state of an animal, which cannot easily be detected by behavioral measurements.     

Is it smart to play the horses? Comment on "A day at the races: a study of IQ, expertise, and cognitive complexity" (Ceci & Liker, 1986)

Ceci and Liker (1986b) presented data that they contended shows two things: (a) Handicapping harness races is a cognitively complex undertaking that can be captured by a multiple regression model, and (b) neither overall skill at handicapping nor the complexity of the mental model used is related to standard measures of intelligence. The first contention is not at issue. But the second contention, that handicapping performance is unrelated to IQ, is not supported by the data presented; in fact, the opposite conclusion seems more likely. The purpose of this comment is to point out errors frequently made in individual-differences research concerning population definition, sample selection, dependent and independent variable reliability and validity and interpretation of results.     

Some tests of the interactive-activation model for word identification

Summary The interactive-activation model postulates (a) that activation at the letter level leads automatically to activation at the word level, (b) that the word-superiority effect reflects reactivation of letters by the word they spell, and (c) that subjects identify words on the basis of information obtained from separate letter-position channels. In the first two experiments, we showed words in upper, lower, or mixed case: the word-superiority effect was reduced when words were presented in mixed-case letters, presumably because extra-letter information is lost with mixed-case presentation; i.e., postulate (c) is wrong. The third experiment showed that when the letters of a word are rotated 180° subjects can identify the letters without producing a word-superiority effect; i.e., one of postulates (a) and (b) is wrong. In Experiments 4 and 5, we trained subjects to name words presented in inverted letters; training was more effective when subjects could exploit bigram information in addition to letter-channel information; i.e., reading inverted text is based on extra-letter-feature information, not on a general skill in rotating letters. Taken together, our data deny three of the interactive-activation model's major postulates. We offer some suggestions for future versions of the model. Electronic mail: Userid: MEWHORTD; Nodeid: QUCDN; Domain: BITNET     

A developmental-genetic analysis of aggressive behavior in mice (Mus musculus): III. Behavioral mediation by heightened reactivity or immobility?

This research was designed to investigate development and behavioral mediation in lines of ICR mice that have been selectively bred for aggressive behavior. General behavioral reactivity and behavioral immobility have been implicated as potential mediators by prior analyses of preattack interactions. To evaluate the separate roles of these dispositions, the emergence of attacks in genetically selected lines was tracked for 11 years by three levels of analysis: over successive generations, over development, and over dyadic interactions. Convergent outcomes were observed in all three levels with respect to two findings: (a) Robust line differences were obtained in attack behaviors, and (b) strong associations were found between line differences in attacks and line differences in behavioral immobility. Conversely, all three levels of analysis indicated a weak and inconsistent association between line differences in attacks and measures of social and nonsocial reactivity.     

Rodents' (Rattus, Mesocricetus, and Meriones) use of learned caloric information in diet selection

When given a choice between two mashes of equal caloric density but differing flavors, rats (Rattus norvegicus) show a robust preference for the flavor previously associated with a higher calorie food. This finding suggests that rats may identify food quality by sensory cues such as taste. Our initial attempt to show this effect in the golden Syrian hamster (Mesocricetus auratus) failed, apparently because of this species's tendency to store both high- and low-calorie mashes in their cheek pouches during conditioning trials. Initially we attempted to circumvent this seeming morphological constraint on learning by presenting low- and high-calorie mashes on alternate days. This procedure too failed to produce evidence of flavor-caloric learning, although this procedure produced robust learning in another rodent, the Mongolian gerbil (Meriones unguiculatus). Another method of preventing cheek pouching--concurrently presenting low- and high-calorie liquid diets--was more successful; then, hamsters showed clear evidence of flavor-caloric learning. Thus, although flavor-caloric learning is demonstrable in species of rodent besides the rat, the circumstances under which it occurs vary.     

Perceptual organization of acoustic stimuli by budgerigars (Melopsittacus undulatus): III. Contact calls

We trained budgerigars by operant conditioning to discriminate among a set of contact calls in a same-different task and analyzed response latencies from this task by using multidimensional-scaling (MDS) and cluster-analysis procedures. Humans listened to the same calls and indicated the similarity between pairs of calls by a direct rating procedure. An MDS program (sindscal) was used to arrange these complex acoustic stimuli in multidimensional space reflecting perceptual organization. Multiple regression techniques were used to identify the acoustic characteristics of contact calls that were correlated with the perceptual dimensions obtained from MDS. A number of spectral characteristics (e.g., peak frequency, rate of frequency modulation, and concentration of spectral energy) emerged as important for both budgerigars and humans, but the relative salience of these cues differed for the two species. Additional tests with two groups of budgerigars--cagemates and noncagemates--showed that experience with calls can change the salience of various acoustic characteristics used for perceptual organization and individual recognition.     

Learning from lectures: The effect of varying the detail in lecture handouts on note-taking and recall

Previous research on the effect of lecture handouts on student learning indicates that students who are given skeletal handouts usually perform better in course examinations than students who take all their own notes. The present study investigates whether the amount of detail in the handout is a critical factor in this. A randomized groups experiment was conducted in the context of a course on dental surgery. Four lecture handout conditions (headings and full text; headings and key points; headings only; no supplementary materials) were compared on tests 2 days and 2 weeks after the lecture. The significant differences between conditions were: ‘headings only’ better than ‘headings and key points’ on the first test; ‘headings only’ better than ‘no supplementary materials’ on the second test; and ‘headings and full text’ better than ‘no supplementary materials’ on the second test. These results indicate that the amount of detail is a critical factor in handout effectiveness.     

Expert knowledge as mnemonic cues

It is proposed that expert knowledge can operate as a cognitive cueing structure for the acquisition and retention of new information in memory. Two experiments are reported which demonstrate that expert knowledge about football and clothing can act as mnemonic cues for the recall of information newly associated with that knowledge. In Experiment 1 expert terms from the domains of football and clothing and those neutral nouns paired with them were both better recalled by experts than by non-experts. In Experiment 2 passages containing information contrary to factual knowledge about football and clothing were recalled better by experts than by non-experts, in spite of the fact that information in the passages contradicted what the experts already knew. The results of the two experiments were interpreted as showing that expert knowledge provides mental cues that have desirable mnemonic properties such as constructibility, associability, discriminability and invertibility. Also, the interpretation of expert knowledge as a cognitive cueing structure is compared to Ausubel's ideas regarding advance organizers.