A mathematical theory of optical illusions and figural aftereffects

If it is assumed that spurious enhancement of receptive field excitations near the intersection of image lines on the retina contributes to the cortical determination of the geometry of two-dimensional figures, an equation based on the least-squares fit of data points to a straight line-can be obtained to represent theapparent line. Such a fit serves as anextreemum on the precision with which a data set can be represented by a straight line. The disparity between theapparent line and the actual line that occurs in the case of peripheral (and to a lesser degree in more central regions of the retina) vision is sufficient to produce the perceptual errors that occur in the Poggendorff, Hering, and Mueller-Lyer illusions. The magnitude of the Poggendorff illusion as a function of the line angle is derived and experimentally tested. Blakemore, Carpenter, and Georgeson’s (1970) experimental data on angle perception are shown to fit this same function. Theapparent curve is derived for the Hering illusion. The Mueller-Lyer illusion is found to be a variation of the Poggendorff illusion. The equations are further developed and used to derive Pollack’s (1958) experimental results on figural aftereffects. The results involve onlyone experimentally determined coefficient that can be evaluated, within the limits of experimental error, in terms of physiological data. The use of these concepts provides a foundation for the abstract modeling of the initial phases of the central nervous system data reduction processes, including receptive field structure, that is consistent with the physiological limitations of the retina as a source of visual data, as well as with the findings of Hubel and Wiesel (1962).     

Natural visual capture in bilateral length comparisons

In left-right comparisons of perceived length, objects on the left were slightly overestimated by vision alone but not by touch alone. This conflict between vision and touch occurred in the absence of any experimentally induced distortion or illusion. Judgments made with concurrent vision and touch were similar to those made with vision alone regardlesa of whether the Os were judging which objectfelt longer,looked longer, orwas longer. The resolution of a natural conflict between vision and touch is an example of natural visual capture.     

Imagery ratings for 338 nouns

This paper reports imagery ratings for 338 nouns by a method similar to that of Paivio. For 111 of the nouns a comparison with ratings reported by Paivio with those reported here yielded a correlation of 0.944. Selection of nouns rated for this study was made from stimulus terms employed in various free-word-association studies.     

Blood glucose and brain function: interactions with CNS cholinergic systems

We recently found that glucose injections attenuate amnesia and hyperactivity produced by scopolamine, a muscarinic antagonist. The present study examined whether glucose would augment behavioral effects produced by a muscarinic agonist, physostigmine. In experiment I, doses were first determined for which neither glucose (10 mg/kg) nor physostigmine (0.05 mg/kg) altered scopolamine-induced hyperactivity. However, combined glucose-physostigmine injections significantly reduced scopolamine hyperactivity. Experiment II evaluated the effects of glucose on physostigmine-induced tremors. Glucose (10, 100, and 250 mg/kg) or saline injections were given 20 min before physostigmine injections (0.4 or 0.05 mg/kg). Observations of glucose effects on the severity of physostigmine-induced tremors were then obtained at 5-min intervals for 25 min after physostigmine injections. Glucose (100 mg/kg) significantly facilitated the onset of tremors when injected before either dose of physostigmine, and augmented (at 100 and 250 mg/kg) tremor severity when injected before the lower dose of physostigmine. These findings indicate that glucose can facilitate the actions of a cholinergic agonist on two behaviors, locomotor activity and tremors, adding support to the view that circulating glucose levels can modulate central cholinergic function. More generally, the results provide additional evidence that circulating glucose levels can influence brain function.     

Modifying food purchases in supermarkets with modeling, feedback, and goal-setting procedures

We compared several procedures designed to modify consumer food purchases with the objectives of reducing fat and increasing carbohydrate content, and reducing dollar expenditures on food. Participants were 126 volunteer community households which, after a 7-week baseline period, were randomly assigned to video-modeling, video-modeling-feedback, video-lecture, video-lecture-feedback, participant-modeling, video-modeling-discussion, and control conditions. The main dependent measure was a weekly record of food purchases, convertible to percentages of nutrients and dollar expenditures. Results indicated that modeling-feedback and participant-modeling procedures were most effective (e.g., 6% reduction of total fat consumption, 19% dollar savings). Strategies to refine and automate modeling and feedback in supermarkets that may benefit consumers, corporations, and government are discussed.     

TWO GENERATIONS OF MOTHERS AND DAUGHTERS: ROLE POSITION AND INTERDEPENDENCE

Using both partners as informants and three interdependence measures (contact, aid, and attachment) as criterion variables, we address the assumption that women's orientation to and dependence on other generations differ because of unique roles. In 135 pairs of student women and their mothers and 119 pairs of middle-aged women and their mothers, we ask how a woman's role position interacts with her partner's role position in regard to interdependence. Both dyadic and individual role combinations are examined. In younger pairs, we examine the combination of daughter's marital status and both mother's launching and work statuses; in older pairs, we examine the combination of mother's marital status and both daughter's launching and marital statuses. Regression analyses demonstrate that, except for younger pairs where married daughters and their mothers are less interdependent than single daughters and their mothers, interdependence is remarkably unrelated to role positions, singly or in combination. Results suggest normative pressures toward new conjugal bonds and stability in women's family roles.     

Primary prevention of behavior problems in mexican-american children

A primary prevention program, the Houston Parent-Child Development Center, directed towards infants and their parents, has effectively reduced the frequency of behavior problems for these children 5 to 8 years after the program's completion. Teacher ratings showed significantly fewer acting-out, aggressive behaviors for program children. Ratings of classroom behaviors found program children significantly less hostile and more considerate than control boys. This appears to be the first primary prevention program to have demonstrated effectiveness in reducing behavior problems over such a long time.     

An analysis of auditory alphabet confusions

The present study, using the nonhierarchical overlapping clustering algorithm MAPCLUS to fit the Shepard-Arabie (1979) ADCLUS model, attempted to derive a set of features that would accurately describe the auditory alphabet confusions present in the data matrices of Conrad (1964) and Hull (1973). Separate nine-cluster solutions accounted for 80% and 89% of the variance in the matrices, respectively. The clusters revealed that the most frequently confused letter names contained common vowels and phonetically similar consonants. Further analyses using INDCLUS, an individual differences extension of the MAPCLUS algorithm and ADCLUS model, indicated that while the patterns of errors in the two matrices were remarkably similar, some differences were also apparent. These differences reflected the differing amounts of background noise present in the two studies.     

The effect of lateral visual fixation on response latency to verbal and spatial questions

The results of several studies have suggested a relationship between lateral eye movements and contralateral hemispheric activation or ipsilateral inhibition. The present study investigated the effects of lateral and central eye fixation on response latency to verbal and spatial questions. Response latencies for verbal questions were significantly longer when subjects fixated to the left or centrally, as compared to the right. On spatial questions, response latencies were significantly longer in the right fixation condition than in the other conditions. The results indicate that visual fixation ipsilateral to hemispheric activation is related to slower problem solving, and suggest that eye movements during cognitive activity may have functional significance.