A feed delivery system for the study of choice behavior in cows

A feed delivery system for the study of choice behavior in cows is described. Supportive data are provided for six dairy cows exposed to two-alternative, concurrent variable-interval schedules.     

THE SKILL OF PICTORIAL PERCEPTION: AN INTERPRETATION OF CROSS-CULTURAL EVIDENCE*

A theoretical framework is proposed for understanding perceptual skills in their functional context. Pictorial perception is construed as a functionally specialised skill whose pervasive importance in modern education derives from the proliferation of pictorial materials in Western culture. Drawing on cross-cultural research, the major components of the skill are identified as (1) detection of appropriate contexts for its application, (2) selection of a limiting frame of reference, (3) use of conventional criteria of fidelity to recognise depicted items, (4) sensitivity to impoverished depth cues, (5) an expectation of finding in the picture most of the information necessary for its disambiguation, and (6) various assumptions about the range of cognitive inferences that may legitimately be made ‘beyond the information given’. Training studies are interpreted as suggesting that the skill can be enhanced through guided experience.     

A repertory grid study of therapist/couple interaction

A case of marital therapy is described in which the presenting problem, one of non-consummation, is treated by the standard Masters and Johnson's technique. Using repertory grids at the start and finish of treatment the changing perceptions of both partners and the therapist were determined. In spite of an ostensibly behavioural treatment, substantial changes occurred in the couple's understanding of the nature of their problem. The changes undergone in the couple's perceptions, and their differences from the therapist's assessments of change give rise to speculations about the nature of the therapeutic interaction and suggest further lines of exploration.     

The effects of binocular and motion-generated information on the perception of depth and height

The perception of distance and size in the presence of optical gradient information was investigated under four viewing conditions—binocular view with and without head motion, and monocular view with and without head motion. Subjects (60 adults) matched distance intervals (from 15 to 127 cm) and heights of a target triangle (from 5 to 15 cm) by adjusting the length of a metal tape. Both linear and power functions were fitted to each individual’s distance judgments, and the competing perceptual models were compared. For both models, it was found that binocular information was sufficient to specify relative, but not absolute, distance, that monocular information was sufficient to specify an orderly relation between target distance and judgment but not absolute distance, that average error was less in the binocular conditions, and that perceived distance was not affected in either condition by the addition of head motion. The analysis of size judgments revealed that monocular and binocular judgments did not differ, that matches made with and without head motion did not differ, and that, in all conditions, matches exceeded target heights by an average 30% to 40%. Judged size was also analyzed as a function of target distance. In all conditions but monocular view with head motion, the effect of distance was to increase size judgments. The distance judgments support the hypothesis (Purdy, 1958) that the binocular stimulus carries information that the monocular stimulus does not; they fail to support the hypothesis (Gibson, 1966) that observer motion adds information to the static stimulus. The size judgments support neither hypothesis but suggest an independence of perceived size from perceived distance.     

The development of automatic word recognition and reading skill

The development of automatic word recognition as a function of reading skill was investigated in three experiments using the Stroop task. Reading skill level ranged from nonreaders to readers above the sixth-grade equivalent. Interference with color naming begins to emerge early in the process of learning to read, increases, and then subsequently decreases. Strings of identical letters delayed color naming for children just beginning to learn to read. The interference from words, presumably reflecting semantic processing, began developing early but did not peak until the second- to fourth-grade reading levels. These different sequences of development of interference in the various stimulus conditions suggest that word recognition is the result of a number of component processes that develop as children acquire skill in reading.     

The family and the child with epilepsy

Reports documenting psychosocial epiphenomena of chronic illness in individuals with that illness have been common in recent years. Few studies, however, have been concerned with how illness might affect the family. Those that have appeared in the literature often lack critical controls (i.e., control groups) and often fail to investigate possible links between illness-specific variables (i.e. chronicity, inhibition of mobility) and psychosocial outcomes on the family. The present study of 45 families focused on how children with epilepsy affect their families' functioning relative to families with a child with diabetes and families with no chronically ill members. The results suggest several areas of child and family adjustment (i.e. child self-concept, family communication, family cohesion) in which the families of epileptic children have great difficulty. Implications of these results are discussed with regard to differential influences of various chronic illnesses on families and family-based preventive and remedial treatment programs.     

Does reward depletion influence spatial memory performance?

If spatial memory tasks are considered as foraging problems, it can be predicted that rats' difficulty in learning a win-stay task—revisiting part of a maze where food has recently been found—should be partly overcome if the food is not fully consumed at the first visit (nondepleted reward) rather than being all eaten (depleted reward). Three experiments confirmed and further analysed this result. Experiments 1 and 2 showed that it does not depend on the amount of food initially found; nor is win-stay performance affected by the amount of food actually eaten. Experiment 3 suggested that the effects of nondepleted reward are mainly due to the animals' being interrupted while eating, and very little to the fact that uneaten food is left behind. The results are discussed with regard to their implications for learning theory, and for the application of foraging theory to learning and memory experiments.