Phonetic prototypes

Speech perception may be viewed as a phonetic categorization task in which the listener assigns incoming sounds to various phonetic categories. The present experiment tests two classes of models of phonetic categorization: (1) models in which the listener has a threshold or boundary between alternative categories vs. (2) models in which the listener compares the input to prototypical representations of the alternative phones. In a pretest, listeners located on a VOT continuum the /ga/ that they thought was prototypical. Selective adaptation was then conducted using both the selected prototype and adaptors nearer and further from the phoneme boundary. The prototype adaptor produced more adaptation than the other adaptors. This result supports a prototype-based representation for phonetic categorization; several process models using such a representation are considered.     

Human patellar reflex and conditioned reflex compared electromyographically

Inspite of continued work on the stretch reflex and “voluntary” movement study of the conditioned stretch reflex declined early in this century. The present experiments surveyed seven classical conditioning regimens for the human rectus femoris EMG seen after a blow to the patellar tendon. It was possible to (1) rule out conditioning to a knee touch that occured together with the tap, (2) establish weak conditioned stimulus, Sc, control for a tape recorder click and subsequent fist clench that preceded the tap by variable elapsed times, and (3) establish strong Sc control for a tone that sounded an invariant 0.27 sec before the tap. There were large differences, however, in Sc power across subjects, as measured by amplitude, latency, and frequency of conditioned EMG activity that occured prior to tap or when the tap was omitted. Purely reflexive responses, especially later EMG segments, also varied in amplitude and frequency, to support a conclusion that numerous controlling stimuli added or competed from trial to trial. Further disclosure of Sc contributions, including those from movement-generated stimulation, is warranted, especially for behaviors whose rhythmic timings, as in locomotion, might favor Pavlovian conditioning.     

Noise stress and circadian arousal in self-paced computation

Previous work(Frankenhaeuser & Lundberg, 1977) has shown that unpaced mental arithmetic is performed at slower rates in noise, despite unchanged catecholamine indices of arousal; only male subjects were used, tested early in the day. Since the times of testing entail arousal effects that interact with noise stress, and the sex of subject further modifies these interactions, a new experiment was designed to include these variables. Men and women were tested on the Norinder mental arithmetic task, in quiet or in noise, either in the morning, when arousal was low, or during the early evening, when temperature curves indicate that arousal should be high. Analysis of the number of problems attempted shows a significant drop for men in noise in the morning, but an interaction due to reversal of the noise effect in the evening; there is no main effect of noise when women's scores are included. The results are compatible with interpretations combining motivation and cognition, and they demonstrate the importance of the experimental variables in explaining noise stress effects.The authors are indebted to the late David A. Shipp for his assistance in running subjects.     

Changes in Moods and Activation Levels During the Menstrual Cycle in Experimentally Naive Subjects

Two experiments providing additional validity data on the Profile of Mood States and the Thayer Activation-Deactivation Adjective Check List were per-formed. In the third and main experiment, seven normally menstruating women filled out both questionnaires at the same time every day for 90 days. They were not aware that they were participating in a study of menstruation. Analysis of the time series records of individual women revealed relatively few significant fluctuations in moods and activation levels. Analysis of the group data showed that Fatigue, Confusion, Deactivation/Sleep, and Depression/Dejection were significantly lower in the premenstrual phase than in the periovulatory phase of the cycle, while General Activation was higher. Anger/Hostility and Confusion were both lower in the menstrual phase than in the periovulatory phase. On a retrospective menstrual distress questionnaire, these same subjects say that they experience increases in anxiety, irritability, depression, and tension in the premenstrual phase of the cycle. The differences between individual and group data and the apparent discrepancy between daily self-reports and retrospective questionnaires are discussed.     

Reminder-induced recovery of associations to an overshadowed stimulus

The possibility of reversing the deficit produced by overshadowing through the use of memory reactivation was investigated. Using lick suppression as a measure of associative strength, water-deprived rats were conditioned in a Pavlovian paradigm which produced reliable overshadowing of a flashing light by a tone. It was found, however, that exposure to the overshadowed stimulus outside of the conditioning context during the retention interval (reminder treatment) caused an increase in lick suppression during testing in animals that had undergone overshadowing, relative to nonreminded overshadowed animals. Subjects that received the reminder treatment but were conditioned without overshadowing showed no increase in lick suppression. Additional control groups ensured that the increase in suppression observed in the overshadowed subjects following reminder treatment was not due to nonspecific fear. The results suggest that the performance deficit produced by overshadowing is due at least in part to a reversible failure to efficiently retrieve associations to the overshadowed stimulus at the time of testing, rather than a failure to form those associations during conditioning.     

Analogical problem solving

The use of an analogy from a semantically distant domain to guide the problemsolving process was investigated. The representation of analogy in memory and processes involved in the use of analogies were discussed theoretically and explored in five experiments. In Experiment I oral protocols were used to examine the processes involved in solving a problem by analogy. In all experiments subjects who first read a story about a military problem and its solution tended to generate analogous solutions to a medical problem (Duncker's “radiation problem”), provided they were given a hint to use the story to help solve the problem. Transfer frequency was reduced when the problem presented in the military story was substantially disanalogous to the radiation problem, even though the solution illustrated in the story corresponded to an effective radiation solution (Experiment II). Subjects in Experiment III tended to generate analogous solutions to the radiation problem after providing their own solutions to the military problem. Subjects were able to retrieve the story from memory and use it to generate an analogous solution, even when the critical story had been memorized in the context of two distractor stories (Experiment IV). However, when no hint to consider the story was given, frequency of analogous solutions decreased markedly. This decrease in transfer occurred when the story analogy was presented in a recall task along with distractor stories (Experiment IV), when it was presented alone, and when it was presented in between two attempts to solve the problem (Experiment V). Component processes and strategic variations in analogical problem solving were discussed. Issues related to noticing analogies and accessing them in memory were also examined, as was the relationship of analogical reasoning to other cognitive tasks.     

The effects of episodic and semantic memory on the identification of sentences masked by white noise

Two studies examine how episodic and semantic memory affect subjects’ abilities to repeat sentences masked by white noise. Subjects first hear a list of 70 sentences that are not masked. Subjects in the framework conditions are told prior to hearing the list that all sentences refer to a contextual framework concerning a deserted island. Subjects in the no-framework groups are not given this information. Subjects in the framework-after condition are given this information only after hearing the list of sentences. Subjects then perform a white-noise identification task. The results indicate that framework subjects are able to identify both old and new framework-related information better than other subjects. Subjects in the no-framework and framework-after conditions identify old information better than control subjects who do not participate in an acquisition phase. Emphasis is placed on the interdependence of episodic and semantic memory, including conditions leading to such interdependence.     

Locus of control and the perception of freedom in an agent of reinforcement

Internals and externals observed a staged videotape presentation that portrayed a “teacher” and a “learner” engaging in a 20-item anagrams task. For externals, any variability (10, 50, and 90% schedule) in the reinforcing behavior of the “teacher” (agent of reinforcement) resulted in significantly greater perceived freedom than when no variability (0 and 100% schedule) occurred in behavior. For internals, perceived freedom was a negative linear function of the amount of reinforcement administered. Internals indicated that they could influence the behavior of the “teacher” in all reinforcement conditions, whereas externals indicated that they could influence only the “teachers” in the variable reinforcement conditions. It was concluded that greater freedom is attributed to a person whose behavior is perceived as congruent with the person's inner disposition.     

Logical relations and comprehension in conversation

This study examines how logical relations (e.g., causality and identity) in spoken discourse affect comprehension. Research on cohesion, which shows that specific unit template structures link discourse and text together, is used to build a model of language comprehension that places template structures at the base of a context comparison operation. Subjects were engaged in ordinary conversation with a confederate trained to produce specific types of logical utterances unobtrusively. The comprehension model predicted that systematically different latencies, topical response, and remedial response of subjects would follow the test items produced by the confederate. The data support the predictions. It is shown that comprehension occurs via one processing path if there is a direct tie between the target item and the immediately prior item in discourse, and a separate processing path if the tie is between the target item and the earlier context. Subject response in conversation is shown to display useful evidence on the nature of comprehension achieved. The findings specify and extend the recent research on the integration of new information into a textual structure.