Specificity of process, response, and stimulus in behavioral bioassays.

Reported 3 experiments which studied aspects of the behavioral specificity of the "biochemical transfer" phenomenon. In Exp I, using 120 common goldfish, an acquisition extract facilitated acquisition but not extinction, while an extinction extract facilitated extinction but not acquisition. In Exp II, using 60 Ss from Exp I and 20 additional Ss, brain extracts facilitated an avoidance response only if they originated in donors that made that same response; extracts from donors that did not respond, although exposed to identical stimuli, did not modify recipient behavior. In Exp III, the biochemical transfer effect was found to be stimulus specific in 48 large and 111 small Ss. Results suggest that the extracts in question are behavior specific and do not generally affect behavior in a global excitatory or global inhibitory way. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response prevention and extinction of escape behavior: Duration, frequency, similarity, and retraining variables in rats.

Describes 3 experiments in which a total of 158 female hooded rats received escape training, response prevention, and then regular extinction. Following training, Ss in Exp I received 1 response-prevention trial lasting 0, 120, 240, or 400 sec, or multiple trials (6, 12, or 20) lasting 20 sec each. Extinction was faster as prevention duration or frequency increased. At each duration, extinction was faster following multiple- than following single-prevention trials. In Exp II Ss received "prevention" in the original escape situation or in similar or dissimilar situations. Extinction was faster as prevention and training situations increased in similarity. To evaluate the persistence of prevention effects, in Exp III Ss received shock retraining between prevention and regular extinction. Retraining attenuated but did not eradicate the effects of prevention. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Experimental study of unconscious influences: Ultrasound as a stimulus.

Used ultrasound as a stimulus to study its effects on behavior without S awareness. In Exp I evoked responses were elicited in 7 of 24 undergraduates by ultrasonic tones when Ss were reporting the presence of no stimulus. In Exp II with 20 male Ss, galvanic skin response conditioning to a compound stimulus made up of ultrasound and a red light resulted in shorter latencies to the compound stimulus than to the red light alone, during extinction. The differences did not appear among control Ss, supporting the occurrence of conditioning without awareness. In Exp III with 16 Ss, reaction-time performance was disrupted by providing ultrasound as an anticipatory cue for 1 of 2 lights over 150 trials and then reversing the ultrasound-light pairing. The ultrasound did not facilitate reaction time to the paired light during the 1st 150 trials, however. Results support learning without awareness, and the method is discussed as it might be extended to the study of unconscious influences and to clinical applications. (75 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Topographic changes in responding during habituation to water-stream simulation in sea anemones (Anthopleura elegantissima).

Investigated habituation of contraction responses in 2 experiments with a total of 7 sea anemones using response-independent and response-dependent intertrial intervals (ITIs). In Exp I, repeated presentation of water-stream stimulation at 4 stimulus durations produced replicable response decrements in 5 out of 6 Ss in the response-independent ITI conditions. 3 Ss habituated repeatedly in the response-dependent ITI condition. Instances of both dishabituation and retention of habituation were observed, and habituation was often accompanied by changes in the topography of responding. In Exp II, habituation retention intervals were assigned values of 30, 60, or 90 min. 2 out of 3 Ss exhibited less responding at the shorter intervals. The data constitute nonassociative learning in individuals of a species lacking a central nervous system. (30 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

False feedback and longevity of the conditioned GSR during extinction: Some implications for aversion therapy.

Investigated the effects of 2 cognitive variables on GSR extinction rates. Exp. I replicated findings that Ss made aware of the onset of nonshocked trials exhibited extinction of a conditioned emotional response more rapidly than Ss not made aware. Exp. I and II (80 and 20 Ss, respectively) further demonstrated that extinction, even under conditions of awareness, can be significantly retarded when false feedback concerning the S's current emotional responsivity is supplied during extinction trials. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of classical conditioning on an internal clock.

Six experiments with 53 male Charles River rats used a psychophysical choice procedure to study the internal clock used to discriminate duration and to investigate whether this clock is sensitive to the signal value (associative strength) of a stimulus. The experiments involved 2 types of trials: On choice trials, a stimulus lasted a short (e.g., 3-sec) or long (e.g., 12-sec) duration; Ss then chose between 2 levers. The rewarded choice depended on the duration of the stimulus. On conditioning trials, the stimulus used on choice trials was presented, but it ended without food (extinction trials) or with food (pairing trials) regardless of what the S did. The main measure of performance was short bias, defined as accuracy with the short stimulus without a corresponding accuracy with the long stimulus. Exp I showed that extinction trials increased short bias relative to training without conditioning trials or to training with pairing trials. Exps II–VI tested explanations of these results. The same results were found when extinction trials were the same duration as the short stimulus (Exp II), when extinction trials were a random duration (Exp V), and when the signal value of the CS was changed in another way (Exp VI). The effect of conditioning trials was modality specific (Exps III and IV). It is concluded that, of the explanations considered, the most valid is that changing the signal value of a stimulus changes how the clock times the stimulus. Reducing signal value reduces the measured duration. (54 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The opioid/nonopioid nature of stress-induced analgesia and learned helplessness.

Investigated whether the same factors that activate the processes that produce escape interference might also activate processes leading to opioid stress-induced analgesia (SIA). Exposure to a variety of stressors produces a subsequent analgesic reaction that is sometimes opioid in nature (reversed by opiate antagonists and cross-tolerant with morphine) and sometimes nonopioid. In Exp I, 40 male albino rats were subjected to 20 min of intermittent footshock, 3 min of continuous footshock, tailshock on a VI schedule, or confinement only. Ss were given escape/avoidance training 24 hrs later. In Exp II, 36 Ss received SIA with a tail-flick apparatus. In Exp III, 40 Ss received inescapable tailshocks or confinement only. In Exp IV, 24 Ss received 2 sessions of footshock before tail-flick was assessed. Both of the opioids SIA procedures produced a learned helplessness effect as assessed by shuttlebox escape acquisition and an analgesia that was reinstatable 24 hrs later. The nonopioid procedures produced neither a learned helplessness effect nor a reinstatable analgesia. These data implicate the learning of uncontrollability in the activation of opioid systems. (33 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of exposure to conditioned stimulus and control of its termination in the extinction of avoidance behavior.

Describes 2 experiments in which, following signaled shuttle box avoidance training, a total of 52 female Fischer344 rats were exposed to the conditioned stimulus (CS) during no-shock treatment trials and subsequently tested during extinction trials in which shock was also absent. In Exp I, Ss that could control the termination of the CS during treatment responded significantly more often during extinction than yoked partners that received the same pattern and duration of CS exposure but could not control its termination. Exp II revealed that the probability of responding during extinction was a decreasing function of the duration of CS exposure during treatment. Thus, in the absence of shock, both lack of control over CS termination and increasing CS exposure each independently facilitated the weakening of well-established avoidance responses. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Appetitive learning and extinction in 11-day-old rat pups: Effects of various reinforcement conditions.

Studied the acquisition and extinction of approach behavior in 96 11-day-old albino Sprague-Dawley rat pups in 3 experiments. The reinforcement in Exps I & II was 15 sec of nonnutritive suckling on an anesthetized lactating female. In Exp I, detention duration, 0- or 15-sec in the goal box on nonreward (N) trials, was studied in 2 groups whose acquisition training consisted of alternating blocks of rewarded and nonrewarded trials with a short (5-sec) intertrial interval. Exp II combined an examination of the effect of detention length with whether or not the mother was physically present, though inaccessible, on N trials with partially or continuously rewarded groups. Detaining Ss on N trials slowed the rate of extinction when the mother was present but increased the rate of extinction when she was absent. There was no evidence of a partial reinforcement extinction effect in any of the groups. The effectiveness of 6 types of reinforcement on promoting acquisition of approach behavior was assessed in Exp III. Equally good acquisition, but differences in extinction was obtained with an adult conspecific as the reinforcer, independent of sex and suckling, but there was no acquisition of approach responding when a sibling or no conspecific was in the goal box. These data extend earlier findings of appetitive learning and extinction in infant rats. They do not support the view that inhibitory mechanisms are absent in the rat until the 3rd or 4th wk of life. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imagery and paired-associate learning.

In Exp. I with 20 undergraduates, the rate of paired-associate learning varied with the type of stimulus, from fastest to slowest: pictures (P), object names (ON), and category names (CN). The stimulus materials did not differ in meaningfulness, and ON had shorter imaginal latencies than CN. The ON-CN difference was replicated in Exp. II with 15 Ss, but presentation of the appropriate P together with an ON or CN on the 1st study trial did not facilitate acquisition of either list. Exp. III with 20 Ss involved the short-term retention of pairs. Using a measure of conditional recall (of responses, given stimulus recall), forgetting occurred over 18 sec., primarily in the 1st 3 sec., but was unaffected by the type of stimulus. The data led to a reevaluation of the conceptual peg hypothesis. (French summary) (17 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hippocampus and trace conditioning of the rabbit's classically conditioned nictitating membrane response.

In 2 experiments, 36 New Zealand albino rabbits received classical conditioning of the nictitating membrane response in a trace conditioning paradigm. In this paradigm, a 250-msec tone conditioned stimulus (CS) occurred, after which there was a 500-msec period of time in which no stimuli occurred (the trace interval), followed by a 100-msec air-puff unconditioned stimulus (UCS). In Exp I, lesions of the hippocampus or cingulate/retrosplenial cortex (CRC) disrupted acquisition of the long-latency or adaptive conditioned response (CR) relative to unoperated controls and Ss that received neocortical lesions that spared the CRC. When Ss with hippocampal or CRC lesions were switched to a standard delay paradigm in which the CS and UCS were contiguous in time, they acquired in about the same number of trials as naive Ss. In Exp II, multiple-unit activity in area CA1 of the hippocampus was examined during acquisition of the trace CR. Ss had a 500-msec trace interval (Group T-500), received explicitly unpaired presentations of the CS and UCS, or underwent conditioning with a 2-sec trace interval. Group T-500 acquired the CR in about 500 trials. Early in training, there was a substantial increase in neuronal activity in the hippocampus that began during the CS and persisted through the trace interval. Later in conditioning as CRs emerged, the activity shifted to later in the trace interval and formed a model of the amplitude–time course of the behavioral CR. (65 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Discriminative shock-avoidance learning of an autonomic response under curare.

Assigned 16 curarized, artificially respirated male Sprague-Dawley albino rats to 2 groups of 8 Ss each, rewarded for intestinal contraction (C) or relaxation (R), respectively. Each S received a predetermined series of CS+, CS-, and blank (B) trials, the latter involving no stimulation. On CS+ trials, Ss in Group C received a noxious electric shock to the tail for episodes of intestinal relaxation, while those in Group R received the shock for episodes of intestinal contraction. Results indicate that both groups spent significantly greater amounts of time, both toward the end of acquisition and during extinction, in the intestinal state for which they were rewarded, manifesting stimulus-specific escape and avoidance learning. In Exp. II with 4 curarized Ss, no consistent unconditioned effects on intestinal motility were observed as a result of shock application or shock offset. (16 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Probability learning on incidentally observed dimensions: A response bias effect.

Performed 2 experiments with 140 university students which demonstrate the occurrence of response bias effects as a function of previous probability learning and which are independent of stimulus dimensions. In Exp I, Ss first received training predicting the alternatives on a brightness dimension of metric patterns on a 70-30 probability distribution with the incidental dimensions of symmetry and concentration varying independently either on 70-30 or 50-50 distributions. After 200 trials, Ss were shifted to an incidental dimension; they predicted dimension alternatives on the incidental dimensions at a rate higher than appropriate controls Ss with no prior training. Exp II demonstrated that the response bias effect was dependent on the nature of the prior probability training. Ss first predicted on a 70-30 distribution of shape and were shifted to either a 70-30 or 50-50 distribution of nonsense syllables. Comparisons with nontraining control groups showed that Ss with prior training predicted the nonsense syllable alternatives at a higher rate. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Monitoring eye movements under conditions of associative matching, response production, and stimulus and response production.

Monitored eye movements in each of 3 studies with 20, 19, and 18 undergraduates, respectively, while Ss were given 8 study trials on a 7-item paired-associate list. Ss were then subjected to a single test trial of associative matching (Exp. I), response production (Exp. III) or stimulus and response production (Exp. IV). A 4th study with 42 Ss, (Exp. II), without eye movement monitoring, involved 3 groups of Ss given either 2, 4, or 6 study trials followed by a single test trial of associative matching. Results, with the exception of Exp. I, were generally consistent with a 2-stage notion of verbal paired-associate learning. (French summary) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Erratum: "Studies in Early Infant Learning: Classical Conditioning of the Neonatal Heart Rate."

Reports an error in the original article by D. H. Crowell et al (Developmental Psychology, 1976[Jul], 12(4), 373-397). Corrections to equations 1, 2, and 3 on pages 381 and 382 are presented. (The following abstract of the original article appeared in record 1976-20687-001.) Three experiments demonstrated that human newborn heart rate level can be reliably modified through classical conditioning procedures. The theory of sensitization served as a frame of reference for Exps I and II, and drive reduction served for Exp III. In Exp I the delay, delay-trace, and control groups, with 10 2-day-old newborns in each, received 5 preconditioning trials of the CS alone, 16 conditioning trials with CS-UCS pairings differing for each group, and 5 extinction trials. Exp II was a replication of the 1st study and involved only the delay and delay-trace groups with 10 infants each. In both studies the delay group curves showed significant monophasic acceleratory responses during extinction. Results support the sensitization hypothesis (i.e., the CR occurring in the interstimulus interval was fashioned out of the response to the CS). In Exp III, the measure of conditioning was the response to the probe technique. 10 experimental Ss received preconditioning trials of nitrogen puff (UCS-sub-1) administered to the abdomen, followed by 10 CS-UCS-sub-2 (500-Hz tone acetic acid) pairings with an interstimulus interval of 3 sec. 10 controls received the same design with a CS-UCS-sub-2 interval of 40 sec. Analyses of the probe stimulus trials showed significant changes for the control group and none for the experimental group. The CS-UCS-sub-2 pairings in the experimental group are interpreted as producing increased drive and adaptive damping of the heart rate response. Findings show that early learning may occur under a variety of conditions and that the results can be incorporated by different theories. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Malleability of conditioned associations: Path dependence.

Using conditioned suppression of barpressing to investigate the stability of a conditioned stimulus–unconditioned stimulus (CS–UCS) association, the present authors gave 151 water-deprived rats either a few pairings of the CS with a strong footshock UCS or many pairings with a weak footshock UCS so that barpress suppression in response to CS was equated. Exp I established training parameters that yielded this equivalence. Specifically, rapid acquisition to a preasymptotic level of responding with strong shock produced suppression comparable to the asymptotic level reached more slowly with weak shock. Exp II showed that although equivalent performance was obtained from extensive conditioning with a weak shock or limited conditioning with a strong shock, only extensive conditioning with weak shock resulted in retarded acquisition of an association between that same CS and a footshock level perceived as midway between the 2 initial training shock intensities as implied by asymptotic performance in Exp I. Exp III demonstrated that the observed retardation in Ss given many conditioning trials with weak shock was CS-specific. It is concluded that the malleability of learned behavior is not simply a function of initial associative strength but is dependent on the path during initial acquisition. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of acute trimethyltin exposure on appetitive acquisition and extinction performance in the adult rat.

16 adult male Sprague-Dawley rats were given an intragastric infusion of 7 mg/kg of trimethyltin chloride (TMT), and 16 additional Ss (controls) received saline, to investigate TMT's effect on Ss' appetitive acquisition and extinction performance. Ss from each condition were divided into 2 equal groups and trained with either partial or continuous reinforcement (PRF or CRF) in a straight-alley maze 21 days after dosing. The acquisition training phase contained 40 trials (4 trials/day) and was followed by 20 trials of extinction training (4 trials/day). Analyses performed on total speed revealed that TMT Ss performed at lower levels during acquisition than controls, regardless of schedule condition. Also, the rate of resistance to extinction was significantly reduced for TMT Ss compared with that of controls, regardless of the training schedules used during acquisition. A PRF extinction effect was observed for both control and TMT Ss, independent of dose regimen. PRF training occasioned greater persistence during extinction than did CRF training. Findings are discussed in terms of issues relating to TMT-induced hippocampal lesions. (19 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Proactive behavioral effects of theta-driving septal stimulation on conditioned suppression and punishment in the rat.

In 2 experiments, a treatment phase of septal stimulation preceded the acquisition of free operant leverpressing on a random-interval 64-sec reinforcement schedule. 32 male Sprague-Dawley rats were chronically implanted with a bilateral septal stimulating electrode and a unilateral bipolar hippocampal recording electrode. Ss received (a) low-frequency (7.7 Hz) stimulation, which drove the hippocampal theta rhythm; (b) random-pulse stimulation (average frequency 7.7 Hz), which produced only nonregular waveforms in the hippocampus; or (c) no stimulation. After 12 days of leverpress acquisition, Ss were presented while leverpressing with an auditory signal associated with a particular schedule of shock delivery: In Exp I, shocks occurred despite the S's response strategy; in Exp II, shocks were delivered only if the S pressed the lever. In both experiments, leverpressing was suppressed by the auditory stimulus. Theta-driving but not random-pulse septal stimulation proactively increased behavioral tolerance to the effects of electric shock. Results support the idea that proactive behavioral effects of septal stimulation are a consequence of the production of the hippocampal theta rhythm. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies in early infant learning: Classical conditioning of the neonatal heart rate.

Three experiments demonstrated that human newborn heart rate level can be reliably modified through classical conditioning procedures. The theory of sensitization served as a frame of reference for Exps I and II, and drive reduction served for Exp III. In Exp I the delay, delay-trace, and control groups, with 10 2-day-old newborns in each, received 5 preconditioning trials of the CS alone, 16 conditioning trials with CS–UCS pairings differing for each group, and 5 extinction trials. Exp II was a replication of the 1st study and involved only the delay and delay-trace groups with 10 infants each. In both studies the delay group curves showed significant monophasic acceleratory responses during extinction. Results support the sensitization hypothesis (i.e., the CR occurring in the interstimulus interval was fashioned out of the response to the CS). In Exp III, the measure of conditioning was the response to the probe technique. 10 experimental Ss received preconditioning trials of nitrogen puff (UCS?) administered to the abdomen, followed by 10 CS–UCS? (500-Hz tone acetic acid) pairings with an interstimulus interval of 3 sec. 10 controls received the same design with a CS–UCS? interval of 40 sec. Analyses of the probe stimulus trials showed significant changes for the control group and none for the experimental group. The CS–UCS? pairings in the experimental group are interpreted as producing increased drive and adaptive damping of the heart rate response. Findings show that early learning may occur under a variety of conditions and that the results can be incorporated by different theories. (79 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Within-compound learning with US presentation in taste aversion.

Determined whether the presentation of a LiCl unconditioned stimulus/stimuli (UCS) disrupts within-compound learning in a taste aversion preparation, using 30 male and 32 female rats in 3 experiments. In Exp I, Ss showed stronger associations between 2 solutions presented in a compound when the compound was followed by LiCl. Exp II showed that an immediate LiCl injection produced stronger flavor–flavor association than a delayed injection. Exp III provided a comparison with Ss that did not receive the treatment to enhance consumption of salty solutions. Results indicate that the effects of Exp II depended on the treatment that altered consumption of 1 component. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)