Preference and response suppression under different correlations between shock and a positive reinforcer in rats

A lever-press response by rats was reinforced by food in two successively presented types of trial signalled by different discriminative stimuli. When responding was punished by a shock in one type of trial, a groups for which the shock always preceded the reinforcer by .5 sec (positive correlation) showed less suppression in those trials than a group which received the shock and food separated in time (negative correlation). When, in a second experiment, rats were given a choice between food alone in one end of a shuttle box and either positively or negatively correlated shock and food in the other on a concurrent schedule, the group receiving the negatively correlated shock showed a greater preference for the food alone end. On the basis of a third experiment in which a tone was substituted for the shock in the choice situation, it was argued that the effect of correlation was not simply due to the stimulus properties of the shock. A final experiment demonstrated that when shock punishment is administered during extinction of the lever-press response, the rate of extinction is slower if the shock has been previously paired with the food reinforcer. Pairing a shock with food seems to attenuate the intrinsic aversiveness of the shock through Pavlovian counterconditioning.     

Semantic focus and sentence comprehension.

Reaction time to detect a phoneme target in a sentence was found to be faster when the word in which the target occurred formed part of the semantic focus of the sentence. Focus was determined by asking a question before the sentence; that part of the sentence which comprised the answer to the sentence was assumed to be focussed. This procedure made it possible to vary position of focus within the sentence while holding all acoustic aspects of the sentence itself constant. It is argued that sentence understanding is facilitated by rapid identification of focussed information. Since focussed words are usually accented, it is further argued that the active search for accented words demonstrated in previous research should be interpreted as a search for semantic focus.     

A search for contrast effects in discrete-trial discrimination learning by pigeons

Behavioral contrast has often been observed in free-operant experiments with pigeons, rarely in discrete-trial experiments with rats. Although Jenkins (1961) and Terrace (1963) have reported a discrete-trial contrast effect in pigeons, a series of experiments reported here found no evidence that latency of responding to S+ in a discrete-trial situation was reliably decreased by alternating reinforced trials to S+ with nonreinforced trials to S?. Latency of responding to S+ was affected neither by the length of the preceding intertrial interval (within the range of 10–60 sec), nor by whether the preceding trial had been to S+ or to S?. The results of two of these experiments suggested that the appearance of positive contrast in Jenkins's experiment was a consequence of differences in the variability of the intertrial interval experienced by control and discrimination groups. In two final experiments, employing standard free-operant procedures, contrast was observed as an increase in rate of responding to S+, but not as a decrease in latency of the first response on each S+ trial. The implication is that contrast effects are more readily observed with the rate measures of free-operant experiments than with the latency measures of discrete-trial experiments.     

Behavioral inference in young children

Three experiments are reported on behavioral inference in children of 3 to 5 years of age. In each experiment the children learned two separate sequences of behavior which they were required to put together in the final test stage in order to obtain a reward. In the first experiment moderate levels of behavioral inference were obtained, although a relatively high proportion of children failed to respond in the test phase. In the second experiment different instructions were used in the test phase, the number of nonresponders was greatly reduced and a much higher proportion of children showed behavioral inference. The third experiment obtained similar results under conditions which excluded the possibility of mediation during a memory test, which was included in the previous experiments. It was concluded that behavioral inference is found, under suitable conditions, in children as young as 3-years-old, and that reports by other investigators of failure to find such inference up to the age of about 8 were due to problems with apparatus and instructions.     

Mental representation of length and weight series and transitive inferences in young children

Forty-eight second graders (8 years of age) were trained on length or weight relationships between adjacent members of a five-term series of colored objects. Feedback was visual and of either minimal or strong salience. Differences in weight were assessed by either a balance scale or a spring scale. Results showed that more salient visual feedback reduced the learning effort for length but not for weight comparisons. After training children were tested on all possible object pairs. Children's comparisons of items by length were very accurate in contrast to their comparisons by weight. An explanation for these findings is suggested by the data from a group of 6-year-olds who were trained on two independent pairs of a four-term series. Test results showed that subjects spontaneously encoded absolute lengths but tended to ignore information about the absolute weight of objects. It is suggested that high test accuracy depends on stimulus material for which the absolute values of the relevant dimension are encoded. The implications for taking test performance as an indicator of “transitive reasoning” ability are discussed.     

Conditioned inhibition is not the symmetrical opposite of conditioned excitation: A test of the Rescorla-Wagner model

Rescorla and Wagner's (1972) linear associative model of learning predicts that a neutral stimulus will become weakly excitatory if it is paired with a conditioned inhibitor and the compound is not reinforced. If the inhibitor is not allowed to extinguish during these pairings, the model predicts that the neutral stimulus will become strongly excitatory. Rescorla (1971) has presented some evidence to support the former prediction of a weak effect. Experiment I tested the latter prediction of a strong effect using rats in a conditioned emotional response paradigm, and found no evidence that the pairings made the neutral stimulus excitatory. Experiment II replicated Rescorla's results, but showed that even on a relearning test the experimental group learned no faster than a novel stimulus control group.     

Acoustic memory and the perception of speech

The nature of acoustic memory and its relationship to the categorizing process in speech perception is investigated in three experiments on the serial recall of lists of syllables. The first study confirms previous reports that sequences comprising the syllables, bah, dah, and gah show neither enhanced retention when presented auditorily rather than visually, nor a recency effect—both occurred with sequences in which vowel sounds differed (bee, bih, boo). This was found not to be a simple vowel-consonant difference since acoustic memory effects did occur with consonant sequences that were acoustically more discriminable (sha, ma, ga and ash, am, ag). Further experiments used the stimulus suffix effect to provide evidence of acoustic memory, and showed (1), increasing the acoustic similarity of the set grossly impairs acoustic memory effects for vowels as well as consonants, and (2) such memory effects are no greater for steady-state vowels than for continuously changing diphthongs. It is concluded that the usefulness of the information that can be retrieved from acoustic memory depends on the acoustic similarity of the items in the list rather than on their phonetic class or whether or not they have “encoded” acoustic cues. These results question whether there is any psychological evidence for “encoded” speech sounds being categorized in ways different from other speech sounds.     

Interactive processes in sentence comprehension and recognition

Two experiments examined the roles played by semantic and surface information in reading and recognizing sentences. Subjects read sentences in normal and inverted typography. Their recognition of meaning and other sentence features was tested using sentences whose typography, wording, and/or meaning were either the same as or different from that in the first set of sentences. In Experiment 1, subjects either read aloud or performed a sentence continuation task. For originally inverted sentences, recognition of meaning was high, irrespective of task demands. For originally normal sentences, recognition was low for Read Aloud subjects and high for Sentence Continuation subjects. Sentence recognition was affected by repetition of wording and typography. Experiment 2 replicated the results with the read aloud task and showed the second reading of originally inverted sentences to be equally swift for paraphrase and verbatim test forms. It was concluded that reading and recognition are interactive processes, involving conceptually driven and data driven operations. The interaction of operations may be either automatic or controlled. While processing of normal typography is automatic, inverted typography induces controlled processing, resulting in better retention. Furthermore, semantic and surface information are conceptualized as interacting components of comprehension and memory processes.     

Activation of bipolar prototypes in attribute inferences

The present study examined how prototypes, as organizational principles of knowledge about persons, affect attribute inference judgments. A distinction is drawn between bipolar and unipolar categories. Two questions are addressed: First, whether only one or both prototypes of bipolar categories like extraversion-introversion are activated in making inference judgments, and second, whether information about the applicability of a stimulus item to a target is processed differently than information about the inapplicability of the stimulus item. The results support the hypothesis that only one prototype is activated and that this is the affirmative one, irrespective of whether the stimulus information is applicable or inapplicable to the target person. The implications of these findings are discussed.     

Intervention and sleeper effects: A reply to Victoria Seitz

Victoria Seitz (Developmental Review, 1981, 1, 361–373) has misperceived and misunderstood our position (A. D. B. Clarke & A. M. Clarke, Developmental Review, 1981, 344–360). For example, our argument endorsed a transactional and not a main-effect model, nor was our aim to argue that early intervention has no important later consequences, nor did we dispute Consortium findings (I. Lazar & R. Darlington, Lasting effects after preschool, Washington, D.C.: DHEW Publication No. (OHDS) 79-30178, 1978). In fact, agreements with Seitz greatly exceed disagreements. Our skepticism about whether a behavioral treatment can have long-range effects without also having earlier ones remains. Long-term changes appear to result from ongoing long-term processes.     

The use of natural consequences and a make-up period to eliminate school phobic behavior: A case study

The school-phobic behavior of a seven-year-old male was modified through implementing a program characterized by maximum parental involvement, restructing of natural consequences, and the use of a make-up period. Full-time school attendance was achieved on the sixteenth day of the program. The advantages of using school personnel as monitors and not as disciplinarians of the school-phobic child's behavior are discussed.     

Dissociation of algorithmic and heuristic processes in language comprehension: Evidence from aphasia

Three groups of aphasic patients, Broca's, Conduction, and Wernicke's, and a nonaphasic patients control group were tested for comprehension of object-relative center-embedded sentences. The sentences were of three types: sentences in which semantic constraints between words allowed the subjects to assign a correct semantic reading of the sentence without decoding the syntax, sentences in which semantic constraints were relaxed and for which a correct reading was only possible with knowledge of syntactic relationships among words, and sentences which described highly improbable events. The subjects' task was to choose which of two pictures captured the meaning expressed in the sentence. Broca's and Conduction aphasics performed near perfectly on sentences where they could use semantic information. Their performance dropped to chance when they had to use syntactic information. These results support a neuropsychological dissociation of heuristic and algorithmic processes based primarily, though not exclusively, on semantic and syntactic information, respectively.     

Filling gaps: Decision principles and structure in sentence comprehension

The correct grammatical characterization of sentences containing filler-gap dependencies is a topic of considerable theoretical interest in linguistics. In some grammatical frameworks, these dependencies are representef in terms of conditions on the permissible indexing of structures (or alternative structure evaluation conditions) which a representation must adhere to in order to be well-formed. In other frameworks, constraints on permissible filler-gap dependencies are simply inherent in the set of phrase structure rules contained in the grammar of a language.The processing of sentences with multiple (potential) filler-gap dependencies was investigated in two experiments. The first experiment provided evidence for three claims. First, the human sentence processor abides by a strategy of assigning the most recent potential filler to a gap. Hence, ‘recent filler’ sentences where this assignment proves to be correct takes less time to comprehend than ‘distant filler’ sentences where this decision turns out to be incorrect. Second, the recent filler strategy is itself just a special case of a more general strategy of assigning the most salient potential filler to a gap. Third, unambiguous sentences in which a filler-gap assignment is disambiguated by ‘control’ information specified by individual verbs gives rise to the same recent filler errors as ambiguous sentences. This suggests that tentative filler-gap assignments are made by the processor before all of the relevant constraints on permissible filler-gap dependencies are consulted by the processor.The second experiment tested an alternative hypothesis that the more complex ‘distant filler’ sentences took longer to comprehend in the first experiment only because these sentences often contained verbs which license two adjacent gaps. The experiment showed that there was a significant recent filler effect in sentences that did not contain adjacent gaps and that this effect did not interact with verb class.The finding that the processor delays use of verb-control information is extremely surprising. It may be explained by the fact that this information is only relevant to one type of gap (‘equi-gaps’) and what type of gap the processor is dealing with often can not be determined unambiguously at the time when it initially encounters a gap in its left-to-right processing of a sentence.If our interpretation of these findings is correct, they argue for a considerable amount of structure in the sentence comprehension system. Further, they favor a view of sentence processing in which processing operations involving constraints on the permissible indexing (or evaluation) of structures lag behind the processor's structure building operations. Hence, the results favor those grammatical theories which preserve this distinction over grammatical theories which provide a uniform characterization of all syntactic well-formedness conditions.