Effects of visual-field and matching instruction on event-related potentials and reaction time

Vertical letter pairs were presented randomly in the left and right visual hemifields in a physical identity match and name identity match condition. The reaction times showed a right visual field superiority for name matches, and a left visual field superiority for physical matches. Event-related potentials to letter pairs showed a sequence of three waves: a negative wave (N2, around 270 msec), a positive wave (P3, around 500 msec), and a broad positive slow wave (SW, around 600-700 msec), respectively. P3 and SW amplitudes were consistently larger at the left hemisphere than at the right hemisphere, regardless of the field of stimulation. At both hemispheres, N2 waves were always larger to stimuli presented in the visual field contralateral to a hemisphere than stimuli presented in the visual field ipsilateral to a hemisphere. The positive waves (P3, SW) showed the opposite pattern: smaller amplitudes to stimuli that were presented contralaterally than stimuli that were presented ipsilaterally to a given hemisphere. These results were attributed to a shift in sustained negativity on the directly stimulated hemisphere, relative to the indirectly stimulated hemisphere, reflecting either sensory at attentional processes in the posterior cerebral hemispheres.     

Spiral aftereffect duration as a correlate of impulsiveness

In a correlational analysis impulsiveness (Imp), assessed by means of a questionnaire concerned with speed of judgment and decision making, was found to be negatively related to spiral aftereffect (SAE) duration. However, this relationship was present only in a sample of subjects with high neuroticism scores. In this group SAE duration was also positively related to debilitating anxiety. A parallel was seen between Imp and Heymans' “Secondary function,” a personality dimension which was similarly operationalized in a visual aftereffect experiment. Some other SAE correlates are also discussed.     

Mechanisms of blocking by contextual stimuli

The influence of contextual stimuli on the conditioning and performance of responding to a discrete stimulus was examined in the US preexposure paradigm using both context shift manipulations and a measure of context conditioning. Four groups of rats received both repeated exposure to an electric shock US in one context (Context 1), and repeated nonshocked exposure to a second context (Context 2). Two additional groups of rats received exposure to these contexts, but never received shock presentations. Rats exposed to shock learned to escape from the stimuli of Context 1, but did not escape from the stimuli provided by Context 2. Rats not exposed to shock failed to escape from either context. All rats then received a single CER conditioning session in which four pairings of a 3-min noise CS and shock US were presented. Half the rats received those CS-US pairings in the excitatory Context 1, while the remaining rats received those pairings in the neutral Context 2. Finally, half the rats in each of the CER conditioning treatments received extinction test trials of the noise CS in Context 1, while the remaining rats received those test trials in Context 2. Thus, this design factorially manipulated the presence of excitatory or neutral contextual stimuli during both conditioning and testing of a discrete CS. In comparison with the two groups of rats never preexposed to shock alone, attenuation in acquisition of conditioned suppression observed during test trials occurred only when CER conditioning had been administered in the excitatory Context 1, and this effect was manifested when testing occurred in either the excitatory Context 1 or the neutral Context 2. These results support the model of R. A. Rescorla and A. R. Wagner (1972) (in A. H. Black & W. F. Prokasy (Eds.) Classical Conditioning II, pp. 64–99, New York: Appleton-Century-Crofts) which asserts that contextual stimuli and sicrete CSs compete for limited associative strength supportable by a given US.     

Asymmetry in reception and retention of colors.

In Experiment 1 a same-different comparison task involving simultaneous discrimination of colors differing by 2.5 steps in hue and presented 2° in the left or right visual field was given to 24 male and 24 female familial righthanders. A significant left visual field superiority was obtained. In a color naming task, the higher the number of color pairs for which both members were given the same name, the larger the left visual field superiority. In Experiment 2 the tasks were replicated with a 10-sec memory interval inserted between the stimuli in each color pair. No significant effects were obtained.     

The role of the magazine-response contingency on signal-directed responding in pigeons

Three experiments used a procedure for directly delivering water into the thirsty pigeon's mouth to explore the role that the instrumental magazine contingency plays in autoshaped responding. Magazine training was accomplished by requiring birds to contact a “magazine” key when it was illuminated, in order to obtain intraoral injections of water. Other subjects received water injections independent of a magazine-response contingency. Subsequently, magazine-trained subjects showed a transient enhancement in responding to the illumination of another “signal” key, whether that stimulus was presented alone or paired with water delivery. The overall level of maintained autoshaped responding was little influenced by the instrumental magazine contingency, although the within-trial time course of signal-directed responding was affected. When illumination of the signal key preceded access to water only when the signal was not contacted, pigeons directed many responses toward the signal key. However, there was no evidence that the instrumental magazine contingency enhanced responding on this omission schedule of reinforcement. These results thus confirm a small, but measurable contribution of the magazine-response contingency to signal-directed responding; they fail to support the conclusion that the instrumental magazine contingency greatly affects the outcomes of autoshaping studies.     

On the consequences of priming: Assimilation and contrast effects

Two experiments investigated the effects of priming (activation of a category by unobtrusive exposure to exemplars of that category) on subsequent judgments in an unrelated task. Subjects were primed with one of four levels of ferocity (size) in the course of a “color perception” experiment, and were later asked to judge the ferocity (size) of real (unambiguous) and unreal (ambiguous) animals. An interaction between ambiguity of judged stimuli (real vs unreal animals) and extremity of primed exemplars (moderate vs extreme levels of ferocity or size) was revealed. Assimilation effects (judgments consistent with the primed category) occurred only when moderate exemplars were primed and ambiguous stimuli judged. Contrast effects occurred when extreme exemplars were primed and ambiguous stimuli judged and, irrespective of extremity of the primed exemplar, when unambiguous stimuli were judged. The results are interpreted in terms of an integration of social judgment and social cognition perspectives.     

Attitude accessibility,attitude-behavior consistency,and the strength of the object-evaluation association

Two experiments were conducted in order to examine the accessibility of attitudes from memory as a function of the manner of attitude formation. The findings of the first experiment indicated that subjects could respond more quickly in a response-time task to inquiries about their attitudes when the attitudes were based upon direct behavioral experience with the attitude objects than when they were based upon nonbehavioral experience. It was suggested that, relative to indirect experience, behavioral experience may facilitate the attitude formation process and increase attitude accessibility once the attitude is formed. A second experiment found support for both of these notions. Two additional experiments indicated that repeated association of the attitude object and the attitudinal evaluation enhanced both attitude accessibility and attitude-behavior consistency. It was suggested that the strength of the object-evaluation association is a critical determinant of accessibility, which, in turn, acts as a central factor in the process by which attitudes affect later behavior. It was further suggested that the manner of attitude formation affects attitude-behavior consistency because direct experience produces a stronger object-evaluation association and, hence, a more accessible attitude than does indirect experience.     

Transfer of the signaling properties of aversive CSs to an instrumental appetitive discrimination

Rats received Pavlovian conditioning in which, based on a shock US, white noise was established for different groups as an aversive CS+, CSo, or CS?. Then, half of each group received the CS contingent upon either the food-reinforced or nonreinforced response in an easy, choice discrimination. Correct responses, i.e., number of reinforcements, to criterion showed that a CS+ for the reinforced response facilitated learning, whereas a CS? retarded learning; conversely, a CS+ for the nonreinforced response retarded learning, whereas a CS? facilitated learning. The same contingency difference occurred with errors to criterion for CS? subjects but was obscured for CS+ subjects apparently by an avoidance-producing effect of the CS+. In support of the generality of the transfer effect, Z-score transforms of the correct-response data showed that the magnitude of transfer was comparable to that obtained in more difficult discriminations. Collectively, the findings indicate that an aversive CS can function as a transformed signal for the presence (CS+) or absence (CS?) of an appetitive reinforcer and that the signal's control of behavior is via a within-chain mediational process.     

Visual behavior of the young human infant: Relationships between chromatic and spatial perception and the activity of underlying brain mechanisms

Two experiments investigated visual attention in human infants. In one experiment, babies looked longer at more than at less saturated colors. In a second experiment, babies looked longer at gratings aligned along the horizontal and vertical orthogonals than along the obliques. Because saturated colors and orthogonal stimulation elicit greater activity in visual system neurons and greater amplitude evoked potentials than desaturated colors or oblique stimulation, these two experiments support the hypothesis that the simple visual stimuli to which infants preferably attend are those that are particularly appropriate in stimulating the geniculostriate or primary visual system. The ethological significance of this taxic mechanism and its utility and function in perception, cognition, and aesthetics are underscored.     

Sexual fantasizing in males and females

Sexual fantasizing during intercourse, masturbation, and nonsexual activity was examined in 30 males and 30 females, American students at Tel-Aviv University. Each subject responded individually to questionnaires involving general background information, sexual activity, daydreaming frequency and attitudes toward daydreaming, and a sexual fantasy scale. The results indicated that virtually no man or woman denied having sexual fantasies. Any observable sex differences were in kind rather than amount of fantasy. Women had more submission fantasies, whereas men reported more performance fantasies. This difference was interpreted as reflecting social sexual stereotypes. In support of a cognitive skill model, it was found that sexual fantasizing proliferates along with increases in both sexual and daydreaming experience. Sexual passivity was related to a greater degree of fantasizing during sex. On the whole, the findings suggest that sexual fantasizing is a universal occurrence which in itself is not necessarily related to psychopathology.     

Memory functioning as related to developmental changes in bases of organization

Two series of object drawings classifiable according to either color or conceptual category were used: one to assess dimensional salience and the other to assess free recall, clustering, and cued recall. Parallel shifts in dimensional salience and the dominance of these dimensions as organizing principles in memory were investigated in nursery school and second- and fifth-grade children. Nursery school children manifested color salience, whereas the two older groups manifested conceptual salience. Above chance clustering according to the salient dimension in each age group and some increase in the size of organization units as a function of age were found. Within age groups, neither amount nor dimension or clustering were related to amount of recall. In each group, more words were accessed by salient than by nonsalient cues. Effectiveness of nonsalient cues depended on the order of presentation for young children, whereas for older chilren they were ineffective regardless of order. Implications of these findings for encoding and retrieval processes in children were discussed.     

The problem-solving strategies of kindergarten and first-grade children during discrimination learning

Kindergarten and first-grade children (6 and 7 years of age, respectively) were given specially designed discrimination tasks with introtact probes preceding each trial. One group (CON) was given the criterion task without prior training. A second group (LTL) received three pretraining tasks of the same type as the criterion task. A third group (HYP) received the same pretraining tasks, but with explicit instructions designed to teach a simple hypothesis-testing strategy. Several indices, designed to reflect the use of win-stay and lose-shift rules, as well as memory for disconfirmed hypotheses, were computed from the protocols of the criterion task. The indices for Group CON suggested that most of these children were using a guessing strategy that involved quite frequent changes in hypotheses. Moreover, many of these children restricted their hypotheses to the irrelevant cues. The indices for Group LTL revealed a spontaneous use of the hypothesis-testing strategy by nearly half of the children. The results for Group HYP indicated that over four-fifths of these children became highly efficient in the use of the problem-solving strategy.     

The development of orientation categories between 2 and 4 months of age

Recent research has indicated that infants are capable of responding to stimuli in a manner indicating that they categorize them. Infant perception of orientation was examined within a framework of categorization. In one experiment, it was shown that 4-month-old infants generalized habituation from one range of oblique grating stimuli to another, consistent with the interpretation that any two oblique stimuli were perceived as more similar than a vertical and an oblique. Four-month-old infants' generalization was not due to a simple inability to discriminate between obliques (Experiment 2) so the results of Experiment 1 reflect in large part true categorization behavior and not categorical perception. Results for 2- and 3-month old infants suggest that "vertical" serves as a reference stimulus in infant orientation perception such that gross distinctions between vertical and nonvertical precede the development of the "oblique" category. The category boundary between oblique and vertical did not successfully predict better between-than within-category discrimination in 4-month-old infants (Experiment 3) under the conditions of these experiments.     

The effect of the temporal locus of the introtact probe on the hypothesis-testing strategies of kindergarten children

The hypothesis-testing behavior of kindergarten children in discrimination learning was studied in a factorial design with two temporal placements of introtact probes (pretrial and posttrial) and two types of pretraining (unidimensional and multidimensional). Pretrial probes consisting of a request for the child's current hypothesis were administered in a conventional manner at the beginning of each trial with the stimuli in view and prior to the choice response. Posttrial probes were administered also with the stimuli in view, but after the choice response had occurred and feedback information had been provided. Learning-to-learn experience in solving three pretraining problems was given either with unidimensional simultaneous problems or with more complex multidimensional problems like the criterion tasks. The results indicated that posttrial probes produced superior local consistency, win-stay, and lose-shift probabilities, relative to pretrial probes, for both types of pretraining. Posttrial probes, however, facilitated learning and the testing of valid hypotheses only for multidimensional pretraining. These results are consistent with the hypothesis that posttrial probes constrain the child to be locally consistent and therefore improve short-term efficiency in hypothesis testing under both pretraining conditions. However, posttrial probes produce an improvement in long-term efficiency, and therefore in learning, only when other components of a successful strategy are acquired as in multidimensional pretraining.     

Generality of persistence: The role of stimulus and response factors in persistence to punishment

Previous research has shown that intermittent punishment of a response increases its persistence to continuous punishment and that intermittent punishment training in one situation produces persistence to continuous punishment in other situations. Experiment 1 showed that as long as the instrumental response and punishing stimulus were held constant from intermittent to continuous punishment marked differences between these situations had no decremental effect on persistence. Experiment 2 showed that intermittent punishment training of one response resulted in substantial persistence to continuous punishment of a different and apparently incompatible response and that such response change had no more than a marginal effect on persistence. The results were seen as requiring some revision to the traditional conditioning-model interpretation of persistence to punishment.     

Inference processes in learning well-defined concepts

In an adaptation of usual experimental techniques for studying the performance of a subject who has to discover a well-defined concept, two theories were independently tested. It was found that Bourne's set of inference operations (Bourne 1974; Salatas and Bourne 1974) predicted fairly well the relative difficulty for the connectives studied (inclusive disjunctive, alternative denial, joint denial, exclusive, exclusive disjunctive) for a stimulus population based on three-valued dimensions but not for a four-valued stimulus population. Reaction times gathered after the subject made no further classification errors fitted the decision-tree structures developed by Hunt et al. (1966). Inspection of the hypotheses subjects made about the rule, revealed two possible major reasoning obstacles: the introduction of a negative attribute and the notion of exception i.e. when the assignment of an attribute in one class depends on another attribute whereas in another class it does not.     

Effectiveness of hand overcorrection for topographically similar and dissimilar self-stimulatory behavior

Response contingent hand overcorrection was used to reduce the frequency of self-stimulatory behaviors in four retarded adult males. For two of the subjects, the treated behaviors (hand shaking and nose touching) involved hand movements which were topographically similar to the hand overcorrection procedure. For the other two subjects, behaviors topographically dissimilar to the treatment procedure were treated (inappropriate laughing and head weaving). All four behaviors were decreased in frequency during treatment. However, the hand overcorrection procedure was more effective with the topographically similar behaviors.