A Brain of Her Own: A Neural Correlate of Song Assessment in a Female Songbird

The song control region in the avian forebrain is a series of discrete, interconnected nuclei mediating song learning and production. It has been studied in males or in species where both sexes sing. Little is known about the neural correlates of song perception in nonsinging females, often the intended recipients of song. We studied cowbirds (Molothrus ater), a species in which only males sing but in which females discriminate between males on the basis of song. We focused on nucleus lMAN because it has been implicated in early song acquisition, a stage relevant to both sexes to choose among competing acoustic models. We found that volume of lMAN was monomorphic in cowbirds. Moreover, the volume and neuronal number of female lMAN were positively correlated with selectivity of copulatory responding. The results provide strong evidence of nonsinging female's use of “song” control nuclei for song perception without the possibility of song production.     

Other mothers: toward an ethic of postmaternal practice

This essay attempts a deliberately perverse interpretation of die new reproductive practices (e.g., contract pregnancy, in vitro fertilization, etc.) in an effort to rethink maternal subjectivity and the bodies that might accompany it.     

INTERNATIONAL MEETINGS

Intercultural relationships in the social science are obviously essential to scientific progress, but collaboration in research and training remains riddled with discontent and practical difficulties. Many of the problems arise from the failure of social psychologists to understand and articulate the basis on which collaboration is necessary and possible. During the last two weeks of June, 1968, twenty-three social scientists representing nine countries assembled at the East-West Center in Honolulu to work on joint research proposals, and to map out a strategy for meaningful interchange.     

On the misuse of manifest variables in the detection of measurement bias

Measurement invariance (lack of bias) of a manifest variableY with respect to a latent variableW is defined as invariance of the conditional distribution ofY givenW over selected subpopulations. Invariance is commonly assessed by studying subpopulation differences in the conditional distribution ofY given a manifest variableZ, chosen to substitute forW. A unified treatment of conditions that may allow the detection of measurement bias using statistical procedures involving only observed or manifest variables is presented. Theorems are provided that give conditions for measurement invariance, and for invariance of the conditional distribution ofY givenZ. Additional theorems and examples explore the Bayes sufficiency ofZ, stochastic ordering inW, local independence ofY andZ, exponential families, and the reliability ofZ. It is shown that when Bayes sufficiency ofZ fails, the two forms of invariance will often not be equivalent in practice. Bayes sufficiency holds under Rasch model assumptions, and in long tests under certain conditions. It is concluded that bias detection procedures that rely strictly on observed variables are not in general diagnostic of measurement bias, or the lack of bias.Preparation of this article was supported in part by PSC-CUNY grant #661282 to Roger E. Millsap.     

Using what children know to improve their learning

Eighty children from three to seven years of age were tested on two forms of a matrix task, one of which was designed to take into account children's limited problem solving skills. The tasks involved seriating nine items (geometric shapes or birds) across two dimensions in a 3 × 3 matrix. The children were required to replace items that had been removed from a matrix board, to reproduce the entire matrix when all items had been removed from the board, and to transpose the matrix, that is, to reproduce the same spatial relations between the items, rotated ninety degrees. Results showed that children performed better when tested using common materials than when they were given standard materials. Furthermore, a greater percentage of children were able to complete the tasks and were able to respond correctly on the first trial of the tasks when using common materials (bird families) than when using the standard geometric shapes. The results were discussed in terms of task variables that influence children's performance and the problems resulting from generating theories of children's cognitive competence based on their performance in specific situations.     

Diagnostic scale for evaluation of graduate-level teaching assistants

The TA Evaluator, 20 5-point ratings of the effectiveness of graduate teaching assistants, showed split-half reliability of .95. All 20 items loaded greater than .59 on a single iterative principal axis factor. Average for 10 items pairs was .55. Use in diagnosis and improvement will be undertaken.     

The influence of stimulus properties on multisensory processing in the awake primate superior colliculus.

Multisensory integration is a process whereby information converges from different sensory modalities to produce a response that is different from that elicited by the individual modalities presented alone. A neural basis for multisensory integration has been identified within a variety of brain regions, but the most thoroughly examined model has been that of the superior colliculus (SC). Multisensory processing in the SC of anaesthetized animals has been shown to be dependent on the physical parameters of the individual stimuli presented (e.g., intensity, direction, velocity) as well as their spatial relationship. However, it is unknown whether these stimulus features are important, or evident, in the awake behaving animal. To address this question, we evaluated the influence of physical properties of sensory stimuli (visual intensity, direction, and velocity; auditory intensity and location) on sensory activity and multisensory integration of SC neurons in awake, behaving primates. Monkeys were trained to fixate a central visual fixation point while visual and/or auditory stimuli were presented in the periphery. Visual stimuli were always presented within the contralateral receptive field of the neuron whereas auditory stimuli were presented at either ipsi- or contralateral locations. Many of the SC neurons responsive to these sensory stimuli (n = 66/84; 76%) had stronger responses when the visual and auditory stimuli were combined at contralateral locations than when the auditory stimulus was located on the ipsilateral side. This trend was significant across the population of auditory-responsive neurons. In addition, some SC neurons (n = 31) were presented a battery of tests in which the quality of one stimulus of a pair was systematically manipulated. A small proportion of these neurons (n = 8/31; 26%) showed preferential responses to stimuli with specific physical properties, and these preferences were not significantly altered when multisensory stimulus combinations were presented. These data demonstrate that multisensory processing in the awake behaving primate is influenced by the spatial congruency of the stimuli as well as their individual physical properties.