A nonparametric procedure for evaluation of true and false positives

A procedure is presented for the evaluation of single-point estimates of true and false positives without strong underlying parametric assumptions. The method is based upon the area operating characteristic and the Green area rule. Estimates of sampling error are also available. The procedure is extended to a strong one-parameter relation between true and false positives.     

Risk of false positives when identifying malingered profiles using the trauma symptom inventory

The Trauma Symptom Inventory (TSI; Briere, 1995) is a 100-item self-report measure of posttraumatic symptomatology that includes an Atypical Response (ATR) validity scale designed to differentiate honest from malingered profiles. In this study, using an analogue design to experimentally manipulate honest and malingered responses on the TSI, we found that proposed ATR cut scores produce a significant risk of false positives. Furthermore, the functioning of proposed cut scores worsened when we used posttraumatic stress disorder relevant samples and low estimates of malingering base rates. In light of these findings, the TSI should be used with caution when assessing claims of posttraumatic stress in forensic or disability settings.     

Luria-nebraska neuropsychological battery: High rates of false positives for geriatirc subjects

This study examined false positive rates obtained for two normal adult age groups, using three different methods for interpreting performances on the Luria-Nebraska Neuropsychological Battery (LNNB). Among normal subjects ages 18 to 30 and ages 65 to 85, false positive rates were found to range from 3.9% to 7.7% for younger subjects and 13.5% to 32.7% for older subjects. Significant differences were found between the proportion of false positives in each age group on each method of interpretation. A lack of agreement was found between the three different methods of interpretation concerningwhich subjects should be classified as impaired. Further analysis was performed by dividing older subjects into two groups, ages 65 to 70 and over 70. False positive rates for subjects over age 70 were found to range from 20.7% to 41.4%. Significant differences were also found between the proportion of false positives in each of these two groups.     

Luria-nebraska neuropsychological battery: High rates of false positives for geriatirc subjects

This study examined false positive rates obtained for two normal adult age groups, using three different methods for interpreting performances on the Luria-Nebraska Neuropsychological Battery (LNNB). Among normal subjects ages 18 to 30 and ages 65 to 85, false positive rates were found to range from 3.9% to 7.7% for younger subjects and 13.5% to 32.7% for older subjects. Significant differences were found between the proportion of false positives in each age group on each method of interpretation. A lack of agreement was found between the three different methods of interpretation concerningwhich subjects should be classified as impaired. Further analysis was performed by dividing older subjects into two groups, ages 65 to 70 and over 70. False positive rates for subjects over age 70 were found to range from 20.7% to 41.4%. Significant differences were also found between the proportion of false positives in each of these two groups.     

Absence of color selectivity in the visual movement aftereffect

Lovegrove, Over, and Broerse (1972) reported that the magnitude of the movement aftereffect was reduced when the colors of the inducing and test stimuli differed, relative to when they were the same. Since this result is contrary to some earlier findings, four experiments were conducted to examine this claim. Neither the duration nor the magnitude (as measured by manual tracking) of the aftereffect generated by rotary or linear movement of contours were found to be affected by the color combinations of the inducing and stationary patterns.     

Selective attention and the organization of visual information

Theories of visual attention deal with the limit on our ability to see (and later report) several things at once. These theories fall into three broad classes. Object-based theories propose a limit on the number of separate objects that can be perceived simultaneously. Discrimination-based theories propose a limit on the number of separate discriminations that can be made. Space-based theories propose a limit on the spatial area from which information can be taken up. To distinguish these views, the present experiments used small (less than 1 degree), brief, foveal displays, each consisting of two overlapping objects (a box with a line struck through it). It was found that two judgments that concern the same object can be made simultaneously without loss of accuracy, whereas two judgments that concern different objects cannot. Neither the similarity nor the difficulty of required discriminations, nor the spatial distribution of information, could account for the results. The experiments support a view in which parallel, preattentive processes serve to segment the field into separate objects, followed by a process of focal attention that deals with only one object at a time. This view is also able to account for results taken to support both discrimination-based and space-based theories.     

Human visual perceptual organization beats thinking on speed

What is the degree to which knowledge influences visual perceptual processes? This question, which is central to the seeing-versus-thinking debate in cognitive science, is often discussed using examples claimed to be proof of one stance or another. It has, however, also been muddled by the usage of different and unclear definitions of perception. Here, for the well-defined process of perceptual organization, I argue that including speed (or efficiency) into the equation opens a new perspective on the limits of top-down influences of thinking on seeing. While the input of the perceptual organization process may be modifiable and its output enrichable, the process itself seems so fast (or efficient) that thinking hardly has time to intrude and is effective mostly after the fact.     

Absence of color-selectivity in Duncker-type induced visual movement

Using a stationary target and moving field, both consisting of gratings of vertical light and dark bars, Over and Lovegrove (1973) reported that, with monoptic viewing, induced target movement is weaker when the light bars of the two components are different in color. This reduction did not occur for dichoptic viewing, for which the aftereffect was almost negligible. Six experiments are described. The effect of different colors was not confirmed, using a stationary point and moving frame or stationary and moving gratings. Reduced effects for different colors and greatly reduced effects for dichoptic viewing occurred only when there was a stationary boundary to the moving bars of the field grating, as in Over and Lovegrove’s experiment. It is concluded that the effect studied by Over and Lovegrove is not the classical induced movement described by Duncker (1929/1938) but one due to periodic coincidence and noncoincidence of moving and stationary bars in grating patterns. This effect is absent when target and field bars are rendered more distinguishable by different colors.     

Reduced effects of pictorial distinctiveness on false memory following dynamic visual noise

High levels of false recognition for non-presented items typically occur following exposure to lists of associated words. These false recognition effects can be reduced by making the studied items more distinctive by the presentation of pictures during encoding. One explanation of this is that during recognition, participants expect or attempt to retrieve distinctive pictorial information in order to evaluate the study status of the test item. If this involves the retrieval and use of visual imagery, then interfering with imagery processing should reduce the effectiveness of pictorial information in false memory reduction. In the current experiment, visual-imagery processing was disrupted at retrieval by the use of dynamic visual noise (DVN). It was found that effects of DVN dissociated true from false memory. Memory for studied words was not influenced by the presence of an interfering noise field. However, false memory was increased and the effects of picture-induced distinctiveness was eliminated. DVN also increased false recollection and remember responses to unstudied items.     

Congruency effect of presentation modality on false recognition of haptic and visual objects

Studying a list of items related to an item that is not presented (lure item) produces a false memory. We investigated whether a haptic study/test results in false recognition and, if so, whether congruency of presentation modality between study and test reduces the false recognition. After haptic or visual study of lists of real objects that are related to a lure object, participants were asked to recognise whether the objects were presented haptically or visually. We obtained false recognition results with haptic study and/or test. False recognition was reduced when presentation and study modalities were congruent. After haptic study, false recognition was reduced in the haptic test, as compared to the visual test. In contrast, visual study always reduced visual false recognition. These results indicate that there is a general effect of retrieval cues that will reduce false recognition.     

Psychometric properties of the Hooper Visual Organization Test

The psychometric properties of the Hooper Vsual Organization Test (VOT) have not been well investigated Here the authors present internal consistency and interrater reliability coefficients, and an item analysis, using data from a sample (N = 281) of "cognitively impaired" and "cognitively intact" patients, and patients with undetermined cognitive status. Coefficient alpha for the VOT total sample was .882. An item analysis found that 26 of the 30 items were good at discriminating among patients. Also, the interrater reliabilities for three raters (.992), two raters (.988), and one rater (.977) were excellent. Therefore, the judgmental scoring of the VOT does not interfere significantly with its clinical utility. The authors conclude that the VOT is a psychometrically sound test.     

The role of test structure in creating false memories

In the Deese/Roediger-McDermott (DRM) paradigm, studying lists of semantic associates results in high rates of false recognition of a nonpresented critical word. The present set of experiments was designed to measure the contribution of additional processing of list items at test to this false memory effect. The participants studied sets of lists and then performed a recognition task for each set. In three experiments, using this paradigm, we investigated false recognition when the number of studied list items presented at test (0, 6, or 12) was manipulated. In Experiments 2 and 3, false recognition of critical lures associated to both studied and nonstudied lists increased significantly as the number of list items included in the test increased. These results indicate that processes occurring at retrieval contribute to false memory effects found with the DRM paradigm.     

Older children's misunderstanding of uncertain belief after passing the false belief test

A four-location belief task was designed to examine children's understanding of another's uncertain belief after passing a false belief (FB) task. In Experiment 1, after passing the FB task, participants were asked what a puppet would do after he failed to find his toy at the falsely believed location. Most 4-year-olds and half of 6-year-olds children who passed the FB test showed difficulty in handling uncertain belief; answering that the puppet would then look for his toy at the current (moved-to) location. Eight-year-old children and adults all recognized that the puppet would look for the toy everywhere, or at random. In Experiment 2, 4- and 6-year-olds were presented two other search tasks; it was shown that preschoolers could use search strategies to solve a similar search problem when FB was not involved. This new aspect of post-FB understanding can be interpreted in terms of limited understanding of uncertainty in a less-knowledgeable individual and of limited ability to infer the consequences of belief-disconfirmation.     

Sound enhances visual perception: cross-modal effects of auditory organization on vision

Six experiments demonstrated cross-modal influences from the auditory modality on the visual modality at an early level of perceptual organization. Participants had to detect a visual target in a rapidly changing sequence of visual distractors. A high tone embedded in a sequence of low tones improved detection of a synchronously presented visual target (Experiment 1), but the effect disappeared when the high tone was presented before the target (Experiment 2). Rhythmically based or order-based anticipation was unlikely to account for the effect because the improvement was unaffected by whether there was jitter (Experiment 3) or a random number of distractors between successive targets (Experiment 4). The facilitatory effect was greatly reduced when the tone was less abrupt and part of a melody (Experiments 5 and 6). These results show that perceptual organization in the auditory modality can have an effect on perceptibility in the visual modality.