The brachium of the inferior colliculus: The human auditory pathways: A quantitative study

Counts of nerve fibers in the brachium of the inferior colliculus in man from birth to 97 years (28 brains) revealed an average on the right of 168,311/mm² and an average of 168,593/mm² on the left. The total fiber population for each level studied averaged 350,562 for section A (immediately adjacent to the inferior colliculus), 452, 372 for section B (center of brachium), and 559,242 for section C (immediately adjacent to the medial geniculate body). These figures were averaged from brains whose ages ranged from 11 to 89 years. The area of the brachium, as well as its total fiber population, increased as the medial geniculate body was approached. This indicates that fibers were entering the brachium at various points along its course from the inferior colliculus to the medial geniculate body or were leaving in the reverse direction. A lower fiber density was found in infant brains, and a loss of nerve fibers was evident in the 91- and the 97-year-old specimens.     

Developmental changes in the semantic processing of pictures and words

Second- and fifth-graders' semantic decision times for pictures and words were analyzed relative to the predictions derived from unitary- and dual-memory models. At both grade levels, word-word response latencies were greater than picture-word latencies which, in turn, were greater than picture-picture latencies. An interaction between Grade and Condition indicated that verbal access times decreased more than pictorial access times. The data fit the predictions of a memory model postulating category storage in a single memory system as opposed to simultaneous representation in verbal and nonverbal memory systems. It was concluded that with increasing experience verbal access to this single semantic system is more rapid.     

Encoding specificity in the recall of pictures and words in children and adults

In this study, the modality of the retrieval cues (pictures or words) was varied in a cued recall task to determine how second and fourth grade children and college adults encode words (Experiment 1) and pictures (Experiment 2). According to the assumptions of the encoding specificity principle, cue modality should affect recall only to the degree to which subjects focus on modality specific (sensory) rather than nonmodality specific (semantic) information in stimuli. In both experiments, the results showed progressively smaller encoding specificity effects with increasing age. To ensure that differences in encoding activity were responsible for these effects, comparisons were made of recall patterns under intentional learn conditions, and under incidental conceptual and sensory orienting conditions. The recall patterns of the children in the conceptual orienting condition were similar to the adult patterns in the learn condition, and the adult recall patterns in the sensory orienting conditions were similar to those of the children in the learn conditions. These results suggest that there are developmental differences in encoding the sensory and semantic information in stimuli that may result from differences in the efficiency with which the semantic information in stimuli is processed. The results suggest that young children typically encode stimuli in a fashion that stresses the sensory aspects of the stimuli, and that recall suffers as a result.     

Development of voice recognition: parallels with face recognition.

Encoding and subsequent recognition of unfamiliar voices was examined in children, aged 6 to 16, and in adults. Performance changed markedly with age, improving sharply between ages 6 and 10, with 10-year-olds approaching adult levels. After age 10 accuracy declined significantly but returned to the adult level by age 14. The course of development closely matches that recently documented for the ability to encode and recognize unfamiliar faces. Several parallels between voice recognition and face recognition are discussed.     

Reading rate and retention as a function of the number of propositions in the base structure of sentences

English texts were constructed from propositional bases. One set of 16-word sentences was obtained from semantic bases containing from 4 to 9 propositions. For another set of sentences and paragraphs, number of words and number of propositions covaried. Subjects read the texts at their own rate and recalled them immediately. For the 16-word sentences, subjects needed 1.5 sec additional reading time to process each proposition. For longer texts, this value increased. In another experimental condition reading time was controlled by the experimenter. The analysis of both the text and the recall protocols in terms of number of propositions lent support to the notion that propositions are a basic unit of memory for text. However, evidence was also obtained that while the total number of propositions upon which a text was based proved to be an effective psychological variable, all propositions were not equally difficult to remember: superordinate propositions were recalled better than propositions which were stucturally subordinate.     

Bilingualism and brain functional asymmetry

The task of the neural organization of the native language, acquired by a direct method and of another language, studied at school, performed correspondingly by the left and the right hemispheres, was studied in the bilingual patient after unilateral electroconvulsive therapy used in psychiatry. It was established that in such a bilingual type the right hemisphere is concerned with the formation of deep semantic structures of the native language while the left hemisphere is responsible for the formation of second language deep structures and of surface structures of both languages. The effect of language learning method on cerebral organization of bilingualism is postulated.     

A developmental study of pronouncing responses in the discrimination learning of words and pictures

Subjects at three age levels were administered picture pair or word pair discrimination lists. They pronounced or pointed as a method of choice, and they pronounced or pointed at the correct item (or remained silent) during rehearsal. The results indicated that with picture pairs, pronunciation facilitated learning as a method of choice and a type of rehearsal in nursery school Ss. For fifth grade and college Ss, there was no significant difference between pronouncing and pointing as a method of choice. However, spoken rehearsal was superior to control performance for fifth grade Ss. College Ss performed equally well in the control and pronouncing conditions, but pointing during rehearsal produced significantly more errors than pronouncing. Word pairs produced no significant pronunciation effects. These results were discussed within an internalization of speech perspective.     

Incentive properties of sucrose and saccharin under different deprivation conditions

In Expt 1 it was found that hungry rats developed a 100% preference for 8% sucrose over water in a maze-choice situation, whereas thirsty rats developed no preference. When deprivation conditions for the two groups were reversed the pattern of preference relations also reversed. In a 2nd experiment nondeprived rats developed a preference for either 8% sucrose or 0.2% saccharin over water while thirsty Ss did not develop a preference for either of these over water. The results are discussed in terms of incentive theory.     

Effects of cooperative,competitive, and individualistic sets on performance in children's groups

Four instructional sets were employed in a study of task performance in triads of first- (age 7 years) and third-grade (age 9 years) children: promotive (equal rewards given to each participant for 12 trials); individualistic (rewards given in proportion to individual performance for 12 trials); contrient-promotive (winner take all for 6 trials followed by equal rewards for 6 trials); and contrient-individualistic (winner take all for 6 trials followed by proportional rewards for 6 trials). Performance under the promotive condition was superior to performance in the other conditions during the first half of the session. Promotive conditions improved performance during the second half of the session in triads that had received contrient instructions earlier but not to levels reached under continuous promotive conditions. Results are discussed in relation to theories of cooperation and competition.     

The effects of hand and direction parameter preknowledge on choice reaction times

The two studies undertaken investigated how reaction times are affected by preknowledge concerning hand and direction parameters, and the order in which these data are disclosed. In the first experiment, preknowledge was manipulated by selecting 2-CRT pairs which had either a common hand or direction component. Reaction signal information content (as defined by the number of unknown response parameters) was controlled, but no parameter differences emerged. When parameter order was manipulated by sequential precuing, the ‘hand then direction’ order conferred a significant advantage. Motor preparation and response selection explanations for this effect are considered. Various difficulties with the paradigms used are discussed, including those of distinguishing between response selection and motor programming contributions, controlling and inferring the strategies adopted by subjects, and defining task difficulty. The prospects for independently fostering either response identification or motor preparation by means of an appropriate selection of precues are also discussed.     

The effects of display and report order asymmetries on lateralized word recognition

Word recognition typically is better or faster in the right visual field than in the left visual field, an effect that often interacts with the handedness of subjects or the phonetic characteristics of the language employed. While these findings suggest a hemispheric locus, it is possible that the field difference is confounded with display or report order asymmetries. Here two experiments manipulate word orientation (horizontal vs. vertical), letter symmetry, and report order variables, and they demonstrate a generalized right field superiority that fails to interact with other factors. Since the superiority appears even when all apparent artifactual asymmetries are eliminated, the findings support a hemispheric interpretation.     

Delayed recognition memory for orientation by human infants

The familiarization/novelty preference paradigm was employed to study the effect of a delay (between the end of the familiarization phase and the beginning of the test phase) on discrimination of the orientation of square-wave gratings by 2- and 3-month-old human infants. Three stimulus pairs were studied: horizontal-vertical, non-mirror-image obliques, and mirror-image obliques. The data indicate that the members of the oblique-oblique stimulus pairs are confused in memory to a greater extent than the members of the horizontal-vertical stimulus pair. These findings are consistent with P.C. Bomba's (1984, Journal of Experimental Child Psychology, 37, 609-636) recent report that infants respond to the orientation of a visual stimulus in a categorical-like manner.     

Mechanisms for the cueing phenomenon: The addition of the cueing context to the training memory

A series of three experiments was run to test the hypothesis that when animals are exposed to a cue from prior training, the context in which cueing occurs becomes associated with the training memory. The first experiment demonstrates that when rats are trained to avoid in one context and then are tested in a different context performance is reduced. Experiments 2 and 3 demonstrate that this performance deficit can be alleviated by cueing the rats in the test context prior to testing. The data suggested that the improved performance does not seem to result from the association of the cueing context with a fear response. These results are discussed in relation to the context addition hypothesis.     

Stimulus factors and listening strategies in auditory memory: An experimental demonstration

Three experiments are reported in which digits spoken at different rates were recalled and monitored. In Experiment I, digits to be recalled were embedded in varying levels of noise. In Experiment II noise was presented only during the inter-digit intervals, either to the same or to the opposite ear as the digits. In Experiment III Ss monitored these sequences for a specified digit and reported its successor. Stimulus rate and signal-to-noise ratio affected perceptual processing time, as evidenced by the frequency and relative proportion of item and order errors. These stimulus factors induce listening strategies that influence the shape of the serial position curve and that persist after stimulus conditions are changed. The data are consistent with a two-stage processing model for the temporal course of speech perception and the nature of listening strategies.     

Categorized and uncategorized attributes as recall cues: The phenomenon of limited access

Our most general proposition is that access to a memory unit is limited to those cues which specify the identifying property of the unit. In our first experiment we had subjects categorize a colored shape by either its shape or color property. Recall for the other member of a unit was faster and better when the cue was the categorized rather than the uncategorized property. In a subsequent experiment evidence was presented which suggested that the asymmetry of the two types of cues was an access rather than an associative asymmetry. Finally, we found that retrieval latency to the uncategorized cue decreased sharply as list length was decreased, while very little effect was evident for the categorized cue, suggesting different retrieval processes for the two types of cues. We are led to infer that when a unit is stored it is also classified and that direct access to that unit is only possible via cues which are specified in the classification system.     

Postdecision evaluation of choice alternatives as a function of valence of alternatives,choice, and expected delay of choice consequences

The effects of valence of alternatives, choice, and expected delay of choice consequences on postdecision evaluations of choice alternatives were studied by either giving subjects a choice between two experimental tasks (both either pleasant or unpleasant) or assigning subjects their initially preferred task. Crosscutting valence and choice, subjects expected either no delay, 10-min delay, or 30-min delay before engaging in the task. All subjects evaluated both tasks immediately after the delay instructions but before experiencing the actual delay. Results confirmed the expected dissonance effect; that is, an upward evaluation of the chosen alternative and a downward evaluation of the rejected alternative, relative to no-choice conditions. Moreover, the relative upward evaluation of the chosen alternative increased as the expected delay decreased. Valence was not found to interact with other variables. The results are discussed in terms of differential salience of choice alternatives.