Shirley C. Peeke

Attention, memory, and cigarette smoking

Four experiments tested the effects of smoking one cigarette on verbal memory and attention. In Experiment I, 18 men were tested under three conditions in a repeated-measures design (pretrial smoking, posttrial smoking, no smoking). Recall of a 50-word list was tested immediately and after intervals of 10 and 45 min. Pretrial smoking resulted in improved recall 10 and 45 min after learing, but not immediately. Posttrial smoking was ineffectual. In Experiment II, three posttrial smoking intervals (1, 5, and 30 min after presentation of a 20-word list) were compared with pretrial smoking and no smoking using a between-subjects design. The 76 light, moderate, and heavy smokers in Experiment II smoked a 1.38 mg nicotine cigarette and were tested 24 h later. Improved recall occurred for pretrial smoking, but not for any posttrial smoking interval and for light and moderate smokers only. Experiment III compared a low (0.40 mg) and high (1.38 mg) level of nicotine cigarette in light and heavy smokers using pretrial smoking. The high-nicotine cigarette resulted in improved recall for both immediate- and delayed-recall tests. The lownicotine cigarette was less effective. Light and heavy smokers different in effect of smoking on heart rate, but not in effect of smoking on recall. Experiment IV found no effect of smoking on depth of processing. The possible mechanisms by which nicotine affects recall are discussed.

Habituation of Conspecific Aggressive Responses in the Siamese Fighting Fish (Betta Splendens)

Mature male Siamese fighting fish (Betta splendens) were presented with a conspecific male confined in a clear plastic tube for either 15 minutes per day for 20 days (group E 15) or 60 minutes per day for 5 days (group E 60). A third group was presented with this aggression eliciting conspecific male stimulus for 15 minutes on days 1 and 2 and again on days 19 and 20. This group (group C 15) was designed to control for post-stimulation waning of aggressive behaviors independent of constant stimulation and also to control for response decrement as a simple function of time. Two components of the aggressive display and frequency of biting were recorded. It was found that with groups E 15 and E 60 all aggressive behaviors habituated. In general, habituation was more rapid with the short stimulation periods than with the longer ones, although qualitative differences were also found and described. Comparisons of groups E 15 and C 15 showed that repeated daily exposures to the aggression eliciting stimulus were necessary to obtain habituation and that two days of 15 minute stimulation followed by 16 days of no stimulation did not result in response decrement on any of the measures recorded.

Combined effects of alcohol and sleep deprivation in normal young adults

The effect of combining sleep deprivation and moderate alcohol consumption in male college students differed from the effects of each treatment alone. Following either alcohol or sleep deprivation, there was mild performance impairment, decreased alertness and reduced amplitude and increased latency of cortical evoked potential (EP) components. Heart rate increased after alcohol and anxiety increased after sleep deprivation. When alcohol and sleep deprivation were combined, antagonistic effects were found for most measures (reaction time, heart rate, alertness, anxiety, latency of early EP components), but synergistic effects also occurred (performance accuracy, latency of late EP components). These effects were found in a doubleblind experiment using 24 subjects. The experimental treatments were alcohol doses of 0, 0.45 and 0.90 ml/kg of 95% ethanol and 0 and 26 h of sleep deprivation.

Effects of two doses of methylphenidate on verbal information processing in hyperactive children

Nine hyperactive children participated in three sessions. During each they were given one of three drugs (placebo, 10 mg, or 21 mg of methylphenidate) in a double-blind crossover study. Following drug administration they were tested on three cognitive tasks. For one task, structural, acoustic, or semantic degrees of encoding of verbal information were induced. Memory for the verbal information was then tested. The 10-mg dose resulted in overall improvement of word recognition and recall. The 21-mg dose did not result in improvement. Amount of improvement was not related to degree of encoding of words. Two other tasks, learning a list of words and visual search of letters from a briefly presented display, were not affected by either the 10- or 21-mg dose. The results indicate that verbal learning can be facilitated by a low dose of methylphenidate but that the dose range may be narrow. Also, certain individuals did not respond favorably to either dose. In discussing the results, the possibility is presented that methylphenidate-induced facilitation may be restricted to certain types of learning or certain methods of assessing retrieval of information.

Alcohol, habituation and the patterning of aggressive responses in a cichlid fish ☆

Territorial cichlids were presented for 30 min with a conspecific male intruder (contained in a clear glass tube). Eight hr prior, 2 groups were administered alcohol (0.15 or 0.30 percent in the aquaria water). A third group served as a control. Three responses were recorded to allow analysis of topographic changes in behavior as well as changes in absolute levels. During the habituation phase, the normal group showed a sequence of long displays, followed by shorter ones as the frequency of attacks increased. The occurrence of threat which gradually gives way to attack is characteristic of the agonistic behavior of this species. In contrast to the controls, the 0.15 percent group was hyperaggressive, while the 0.30 percent group was hypoaggressive. Furthermore, the patterning of responses were abnormal. The 0.15 percent group gave abbreviated threats and more attacks (interpreted as a tendency to attack without warning); whereas, the 0.30 percent group gave many long threat displays, but few attacks. A stimulus specificity test provided strong evidence that the waning found during the initial phase was habituation.

Habituation, reinstatement and recovery of predatory responses in two species of teleosts, Carassius auratus and Macropodus opercularis

Abstract The tendency for predatory responses to habituate and to be reinstated through sensitization and the passing of time was studied in two species of fish (the goldfish and the paradise fish). Prey (live brine shrimp), confined in a clear plastic tube were presented for short daily exposures to individual fish. Bites directed at the stimulus tube containing the prey were the primary response measure. In both species biting decreased significantly over the 6 days of the experiment. Reinstatement of the habituated response occurred by two means: (1) reinforcement (i.e. allowing the fish to chase and consume the prey), and (2) passing of time (10 days) with no intervening stimulation (recovery). Reinstatement could not be produced by presenting a novel stimulus, nutritive stimuli, nor by a shorter recovery interval.

Long-term memory deficits for habituation of predatory behavior in the forebrain ablated goldfish (Carassius auratus)

Abstract Forebrain-ablated, sham-operated, and normal goldfish were presented with 40 live brine shrimp confined in a clear plastic tube for 10 min on each of 5 successive days. The predatory responses (bites) directed at the brine shrimp waned similarly for all groups on day 1, indicating no deficit in inhibition or in short-term memory. The normal and sham-operated groups showed complete savings of the previous days experience on subsequent days, indicating good memory for the first days habituation. The forebrainless fish showed essentially no savings between days, suggesting a deficit in long-term memory. The experimental paradigm makes it difficult to interpret the results according to nonspecific arousal or inhibitory explanations.

Effects of practice on marijuana-induced changes in reaction time

The effect of smoked marijuana on performance of complex reaction time (RT) tasks was studied in two groups receiving different amounts of practice. Group M-P had no undrugged practice on the task before performing during marijuana intoxication for four consecutive daily sessions. On the fifth test day they performed while non-intoxicated. Group P-M performed the task on four consecutive test days while non-intoxicated, then smoked marijuana on session 5. Significant RT slowing was found on session 1 for group M-P (performing during marijuana intoxication without prior practice). Performance of this group improved rapidly and by the end of session 2 was not different from undrugged performance. Group P-M (receiving four sessions of undrugged practice before marijuana intoxication) showed no RT slowing while intoxicated. Reaction time performance may involve two phases: an early, attention-demanding phase which is sensitive to drug effects and a later, “automatic”, phase which results from practice and is more resistant to drug effects.Pulse rate, salivary flow and subjective responses were recorded before and after smoking. These physiological and subjective measures showed only slight reduction in the acute effects of the drug over the four days of repeated usage.

Effects of alcohol congeners and acetaldehyde on aggressive behavior of the convict cichlid

Ethanol and three beverage alcohols were examined for their effects on the aggressive responses of the convict cichlid. At an ethanol concentration that gave negligible effects on the basal level of these responses, rum was observed to depress aggression. As its concentration of acetaldehyde was significantly higher than that of the other beverage alcohols, we assessed the effects of acetyldehyde on the aggressive responses, as well as the locomotor activity of the fish. At 4mg/l, acetaldehyde completely inhibited aggressive responses, without affecting locomotor activity. It is likely, however, that acetaldehyde does not explain the entire inhibitory effect of rum on the aggressive responses of the cichlid.

Relative frequency of attribute relevance and response times in visual search

Two experiments, one using a between-Ss and one a within-Ss design, showed that response latencies to single attribute probe stimuli were longer when the target stimulus embodied two attributes (form and color) rather than a single attribute. The magnitude of this “mixed attribute effect” was influenced by the probability of attribute relevance, but the “probability effect” was mostly due to a “repetition effect,” such that latencies on trials involving repetitions of the same attribute were shorter than when the relevant attribute was shifted. Implications of these results are drawn for the issues of holistic vs attributized representation of the target stimulus and serial vs parallel search of a set of attributes. Although no class of models can be ruled out on the basis of these experiments, constraints can be imposed on the versions of each that are compatible with the data presented.