A comparison of binary and rating techniques in the signal detection analysis of recognition memory

Forty-eight subjects were run on a recognition memory task employing low, medium, or high meaningfulness (m) CVC items and utilizing either a binary (yes—no) or rating response technique. Significant differences were obtained between levels of m with higher m items resulting in larger d' values. The interaction term was also significant reflecting a large difference between the binary-rating techniques with high meaningfulness items. The results indicate that the binary and rating techniques do not reveal identical findings in the analysis of recognition memory data and that the frequent use of the rating technique by researchers in the analysis of memory data may not be appropriate.     

Relational responses in tests of transposition with Rhesus monkeys

Three adult Rhesus monkeys (Macaca mulatta), one with nonrelated discrimination learning experience and two experimentally naive, were trained to discriminate between two simultaneously presented stimuli differing only in height. After exceeding the learning criteria on a VR 4 reinforcement schedule and considerable overtraining, subjects were tested for transposition. Both upward and downward and near and far tests were administered to determine the effects of distance from the original training pair on the amount of transposition. In these tests, each of the 24 stimulus pairs contained one or more novel stimuli. Training trials were interpolated to avoid extinction effects and measures were taken to avoid motivational deficits or differential rewards during testing. All three subjects responded relationally at far as well as near distances from the original training pair. Stimulus generalization, on the basis of increments of association, was found to be an inferior explanation for these data. Slight decrements on far tests can be better explained in terms of the learning-performance distinction.     

Parallel discrimination of subjective contours defined by offset gratings.

Recent physiological studies (von der Heydt & Peterhans, 1989) suggest that the orientation of subjective contours is encoded very early in the visual system (V2 in monkey). This result is seemingly at odds with existing psychophysical data which suggest that the detection of subjective contours involves selective attention. It is argued that certain subjective contours are registered in a reflexive (bottom-up) manner by the visual system but that selective attention may be needed to gain access to this representation. To assess this suggestion, a visual-search task was used in which subjects were to detect the presence of a horizontal (vertical) subjective contour (defined by offset gratings) in a variable number of vertical (horizontal) subjective contours (also defined by offset gratings). When there were no competing organizations within the display, detection was indeed independent of the number of nontarget distractors, that is, selective attention was unnecessary. In a second experiment, we found that a curved form (a crescent defined by subjective contours) was easier to detect in a background of vertical bars (also defined by subjective contours) than vice versa, namely, a search asymmetry paralleling those found by Treisman and Gormican (1988). A final experiment showed that when the horizontal and vertical bars of the first experiment formed textured regions, they could be discriminated at very brief display durations (30-120 msec). However, when the line terminations aligned along the subjective contour were tapered rather than abrupt, discrimination dropped off with the degree of tapering. The latter result is consistent with the assumption that the registration of subjective contours in V2 involves the integration of responses from aligned, end-stopped cells found in V1 (von der Heydt & Peterhans, 1989).     

Detection and discrimination of subjective contours defined by offset gratings

Three experiments were conducted to refine our understanding of the mechanisms that encode subjective contours. In Experiment 1, discrimination thresholds (stimulus onset asynchronies [SOAs] yielding 81% correct) were measured in a backward masking paradigm for subjective contours defined by offset gratings. For large apertures, thresholds increased as carrier frequency increased. For the smallest aperture, thresholds were a U-shaped function of carrier frequency. Experiment 2 showed that these threshold results were generally consistent with the rated strength of the subjective contours. Experiment 3 showed that detection thresholds (SOAs yielding 81% correct) again increased with carrier spatial frequency, increased for obliquely oriented carriers, and, for a particular frequency and orientation of the carrier, were lower when the subjective contour was orthogonal to the carrier. All of these results are well explained by a two-stage process in which a second-layer filter integrates the responses of end-stopped mechanisms to the terminators defining the subjective contour. In the model, the end-stopped mechanisms have low-pass sensitivity to carrier spatial frequency, and the sizes of the second-layer filters are proportional to the scale of the end-stopped mechanisms from which they draw their input.     

Preattentive and cognitive effects on perceptual completion at the blind spot

Our findings indicate that preattentive processes, such as the filling in of homogeneously colored areas, discrete dots, or bars across the blind spot, take into account both the color and the form that stimulate the retina around the optic disk. Perceptual completion of the “junction” of two opposite colors facing each other on opposite sides of the blind spot was resolved by simultaneous segregation of the two colors at the location of a filled-in perpendicular line that suggested a boundary separating the two colors. Orientation preference and relative salience of one color versus the other determined which color was perceptually completed in a forced-choice situation that involved perceptual completion at the intersection of a cross formed by bars of opposite colors. A 1-min exposure to these stimuli presented an ambiguous situation for perceptual completion of either color within the blind spot, and resulted in a perceptual “flip-flop” from one color to the other, much like the phenomenon that occurs in figure reversal. Instructions to speed up this reversal process led to a fivefold reduction in latency to first reversal.     

Effects of a school-based cognitive-behavioral intervention for ADHD children

Two variations of school-based cognitive-behavioral training (CBT) program were compared to each other and to a waiting-list control condition in the treatment of children with attention-deficit hyperactivity disorder (ADHD). The experimental interventions included a multicomponent condition that provided coordinated training programs for parents, teachers, and children and a teacher-only condition that offered training for classroom teachers only. Evaluation of outcome occurred at pre-intervention, post-intervention and at 6-week followup periods. Depedent measures included classroom behavior observations, teacher ratings of child behavior, child self-report, and teacher ratings of adjustment. The multicomponent CBT condition was significantly better than the other conditions at improving observed off-task/disruptive behavior at post-test. This improvement was maintained at followup, although treatment condition differences were no longer significant. There were no treatment condition differences on any other measures at postintervention or followup. It was concluded that the intervention had minimal short-term effects on the ADHD children. The results are discussed within the context of several methodological limitations of the study which serve as proposals for continued research in this area.The authors gratefully acknowledge the support and assistance of the faculty and staff at Echo Park, Cedar Park and Westview Elementary Schools (Rosemount, MN, Independent School District), and the parents and children who participated in this study. The authors would also like to extent special thanks to the principals of these schools, Mr. Robert Keaton, Mr. William Mack and Mr. Marvin Skinner, and the school psychologists servicing these schools, Ms. Sheila Peterson, Ms. Ann O'Brien, and Mr. Mark Kaloski, for their commitment and service to children with attention-deficit hyperactivity disorder.     

Family work with victims and offenders in a secure unit

Two examples of family therapy in a secure unit for violent mentally ill offenders are described. The model used incorporated ideas from reparation schemes for victims and offenders in addition to an emphasis on the circumstances of the offence.     

Local and global mechanisms of one- and two-dimensional orientation illusions

One-dimensional (1-D) orientation illusions induced on a test grating by a tilted and-surrounding 1-D inducing grating have a well-known angular function that exhibits both repulsion and attraction effects. Two-dimensional (2-D) orientation illusions are those induced on a test grating by 2-D image modulation, such as a pair of superimposed inducing gratings at different orientations, usually orthogonal (a plaid). Given the known angular functions induced by the plaid component gratings, two hypotheses were developed that predicted different plaid-induced illusion functions. Hypothesis 1 states that the 1-D component-induced effects simply add linearly; Hypothesis 2 states that there is an additional mechanism that responds to the virtual axes of mirror symmetry of the plaid and adds to the effect. The data of two experiments were consistent with the predictions from the second hypothesis but not the first. Possible neural substrates of mechanisms that extract axes of symmetry are discussed; it is suggested that such global symmetry axes may underlie the perceived orientation of complex shapes.