Adaptive changes of response criterion in recognition memory

An experiment was conducted to investigate people’s ability to vary a response criterion strategically, in a recognition memory task, as a function of the length of time given to process the test stimuli (from 100 to 1,500 msec). The experiment used the response signal procedure, in which the participants responded after a signal that came at a variable time delay from stimulus onset. The proportion of new versus old test items was varied systematically with the time of the response signal, with the proportion of new test items rising, falling, or staying constant at later signals. It was found that the participants’ response biases changed adaptively, becoming more conservative at later signals in the rising condition, becoming less conservative in the falling condition, and not changing significantly in the constant condition. Theoretical and methodological implications for recognition memory research are discussed.     

Age-related changes in children's hedonic response to male body odor

Male sweat smells disgusting to many adults, but it is unclear whether children find it so. In Experiment 1A, children (mean age = 8.7 years) and adolescents (M=16.6 years) smelled male sweat and other odors, rated each for liking, and attempted their identification. Only female adolescents disliked male sweat and could identify it. Experiment 1B, using the same procedure, obtained this gender difference in adults (M=26.7 years). In Experiment 2, children (M=8.1 years) and adolescents (M=16.6 years) were cued about the identity of the same odors. Irrespective of gender, adolescents disliked male sweat more than did children. In sum, dislike for the odor of male sweat may be an acquired social response that is based on odor identification.     

Age-related deficits in face recognition are related to underlying changes in scanning behavior

Previous studies demonstrating age-related impairments in recognition memory for faces are suggestive of underlying differences in face processing. To study these differences, we monitored eye movements while younger and older adults viewed younger and older faces. Compared to the younger group, older adults showed increased sampling of facial features, and more transitions. However, their scanning behavior was most similar to the younger group when looking at older faces. Moreover, while older adults exhibited worse recognition memory than younger adults overall, their memory was more accurate for older faces. These findings suggest that age-related differences in recognition memory for faces may be related to changes in scanning behavior, and that older adults may use social group status as a compensatory processing strategy.     

Strength-based mirror effects in item and associative recognition: Evidence for within-list criterion changes

Strength-based mirror effects occur when the hit rate is higher and the false alarm rate is lower following strongly encoded study lists than when following more weakly encoded study lists. In Experiments 1A and 1B, strength-based mirror effects were observed in separate tests of single item and associative recognition for random word pairs. In Experiment 2, strength-based mirror effects were again seen when item and associative recognition were tested together. Finally, in Experiments 3 and 4, opposing strength-based mirror effects were observed for item and associative recognition when individual words and word pairs were presented at different rates in the same study lists. Strength-based mirror effects could result from participants' adopting a more conservative decision criterion following strong lists than following weak ones. If this is the case for both item and associative recognition, the present results demonstrate that subjects can adopt different response criteria for different recognition tasks and can alternate between them on a trial-by-trial basis.     

Brain activations associated with shifts in response criterion on a recognition test.

Sensitivity and bias can be manipulated independently on a recognition test. The goal of this fMRI study was to determine whether neural activations associated with manipulations of a decision criterion would be anatomically distinct from neural activations associated with manipulations of memory strength and episodic retrieval. The results indicated that activations associated with shifting criteria (a manipulation of bias) were located in bilateral regions of the lateral cerebellum, lateral parietal lobe, and the dorsolateral prefrontal cortex extending from the supplementary motor area. These regions were anatomically distinct from activations in the prefrontal cortex produced during memory-based retrieval processes (manipulations of sensitivity), which tended to be more medial and anterior. These later activations are consistent with previous studies of episodic retrieval. Determining patterns of neural activations associated with decision-making processes relative to memory processes has important implications for Cognitive Neuroscience, including the use of these patterns to compare memory models in different paradigms.     

Conflict and criterion setting in recognition memory

Recognition memory requires both retrieval processes and control processes such as criterion setting. Decision criteria were manipulated by offering different payoffs for correct "old" versus "new" responses. Criterion setting influenced the following late-occurring (1,000+ ms), conflict-sensitive event-related brain potential (ERP) components: the stimulus-locked late posterior negativity (LPN) and the response-locked error-related negativity (ERN). The LPN-ERN were most negative to hits under conservative payoff conditions involving conflict between the correct old response and the payoff for new responses. This same conservative-hit condition was most frequently associated with response reversals when fast initial judgments were followed by slower judgments. Postresponse ERP activity may index conflict-sensitive processes underlying postretrieval cognitive control mechanisms involved with assessing responses to current items and updating response criteria on later trials.     

Strength-based criterion shifts in recognition memory

In manipulations of stimulus strength between lists, a more lenient signal detection criterion is more frequently applied to a weak than to a strong stimulus class. However, with randomly intermixed weak and strong test probes, such acriterion shift often does not result. A procedure that has yieldeddelay-based within-list criterion shifts was applied to strength manipulations in recognition memory for categorized word lists. When participants made semantic ratings about each stimulus word, strength-based criterion shifts emerged regardless of whether words from pairs of categories were studied in separate blocks (Experiment 1) or in intermixed blocks (Experiment 2). In Experiment 3, the criterion shift persisted under the semantic-rating study task, but not under rote memorization. These findings suggest that continually adjusting the recognition decision criterion is cognitively feasible. They provide a technique for manipulating the criterion shift, and they identify competing theoretical accounts of these effects.     

Age-related changes in visual pseudoneglect

Pseudoneglect is a slight but consistent leftward attentional bias commonly observed in healthy young populations, purportedly explained by right hemispheric dominance. It has been suggested that normal aging might be associated with a decline of the right hemisphere. According to this hypothesis, a few studies have shown that elderly tend to exhibit a rightward attentional bias in line bisection. In the present study, we tested this hypothesis in young and older participants using a perceptual landmark task. Results yield evidence for an age-related shift, from a strong attentional leftward bias in young adults toward a suppressed or even a reversed bias in the elderly. Right hemisphere impairment coupled to a left hemispheric compensation might explain the perceptual shift observed in older adults. However, a decline in corpus callosum function cannot be excluded. Alternatively, these results may be in agreement with the hypothesis of an age-related specific inhibition of return dysfunction, an overt attentional orienting mechanism, and/or a decrease of dopamine.     

Age-related changes in odor discrimination

Odor naming and recognition memory are poorer in children than in adults. This study explored whether such differences might result from poorer discriminative ability. Experiment 1 used an oddity test of discrimination with familiar odors on 6-year-olds, 11-year-olds, and adults. Six-year-olds were significantly poorer at discrimination relative to 11-year-olds and adults, who did not differ. Experiment 2 used the same procedure but with hard-to-name visual stimuli and compared only 6-year-olds with adults (as with the remaining experiments in this study). There was no difference in performance between these groups. Experiment 3 used the same procedure as Experiment 1 but with less familiar odors. Six-year-olds were significantly poorer at discrimination than adults. In Experiment 4 the researchers controlled for verbal labeling by using an articulatory suppression task, with the same basic procedure as in Experiment 1. Six-year-old performance was the same as for Experiment 1 and significantly poorer than that of adults. Impoverished olfactory discrimination may underpin performance deficits previously observed in children. These all may result from their lesser experience with odors, relative to adults.     

Cue quality and criterion setting in recognition memory

Previous studies on how people set and modify decision criteria in old-new recognition tasks (in which they have to decide whether or not a stimulus was seen in a study phase) have almost exclusively focused on properties of the study items, such as presentation frequency or study list length. In contrast, in the three studies reported here, we manipulated the quality of the test cues in a scene-recognition task, either by degrading through Gaussian blurring (Experiment 1) or by limiting presentation duration (Experiment 2 and 3). In Experiments 1 and 2, degradation of the test cue led to worse old-new discrimination. Most importantly, however, participants were more liberal in their responses to degraded cues (i.e., more likely to call the cue “old”), demonstrating strong within-list, item-by-item, criterion shifts. This liberal response bias toward degraded stimuli came at the cost of increasing the false alarm rate while maintaining a constant hit rate. Experiment 3 replicated Experiment 2 with additional stimulus types (words and faces) but did not provide accuracy feedback to participants. The criterion shifts in Experiment 3 were smaller in magnitude than Experiments 1 and 2 and varied in consistency across stimulus type, suggesting, in line with previous studies, that feedback is important for participants to shift their criteria.     

Age-related changes in auditory temporal processing

Two tone bursts separated by a silent interval and imbedded in a background white noise were presented to elderly subjects (M age = 71.3 years) and young subjects (M age = 22.2 years). Subjects were required to judge when the two tone bursts fused perceptually by adjusting the duration of tone-one. The bursts were separated by six discrete interstimulus intervals of 4, 8, 16, 24, 32, or 40 ms. The tone-two burst was held constant at 100 ms. Fusion point was defined as that critical tone-one duration at which the two tones fused (were perceived as one). Elderly subjects reached fusion point at longer critical tone-one durations than young subjects at each interval tested. The function relating tone-one duration and interval conformed to an exponential curve and is discussed with respect to an exponential decay model of the inhibitory interactions of neural systems responding to onsets and offsets of sensory events.     

Age-related changes in auditory temporal perception

The discrimination of signal and silence duration was evaluated in 6-month-old infants, 5 1/2-year-old children, and adults. Listeners were tested with a conditioned-discrimination procedure in which they were presented a sequence of 18 white-noise bursts and trained to discriminate a change in duration of the middle 6 signal or silence elements. There were no differential effects on performance for changes in signal compared to silence duration. At each age, performance varied only as a function of magnitude of duration change. Infants discriminated duration changes of 20 ms or greater, children discriminated 15 ms, and adults discriminated changes as small as 10 ms. These findings are consistent with other research in revealing age-related improvements in auditory temporal perception.     

Age-related changes in contextual associative learning

The hippocampus plays a critical role in processing contextual information. Although age-related changes in the hippocampus are well documented in humans, nonhuman primates, and rodents, few studies have examined contextual learning deficits in old rats. The present study investigated age-related differences in contextual associative learning in young (6 mo) and old (24 mo) rats using olfactory stimuli. Stimuli consisted of common odors mixed in sand and placed in clear plastic cups. Testing was conducted in two boxes that represented two different contexts (Context 1 and Context 2). The contexts varied based on environmental features of the box such as color (black vs. white), visual cues on the walls of the box, and flooring texture. Each rat was simultaneously presented with two cups, one filled with Odor A and one filled with Odor B in each context. In Context 1, the rat received a food reward for digging in the cup containing Odor A, but did not receive a food reward for digging in the cup containing Odor B. In Context 2, the rat was rewarded for digging in the cup containing Odor B, but did receive a reward for digging in the cup containing Odor A. Therefore, the rat learned to associate Context 1 with Odor A and Context 2 with Odor B. The rat was tested for eight days using the same odor problem throughout all days of testing. The results showed no significant difference between young and old rats on the first two days of testing; however, young rats significantly outperformed old rats on Day 3. Young rats continued to maintain superior performance compared to old rats on Days 4-8. The results suggest that aging results in functional impairments in brain regions that support memory for associations between specific cues and their respective context.     

Age-related changes in implicit emotion processing

The aim of the present study was to compare the performance of older and younger adults on an emotional priming task. Moreover, a nonemotional priming paradigm was used as a control task to disentangle age-related changes due to emotional processing difficulties from modifications due to a decline of executive inhibitory control abilities. Twenty-two young and 22 older healthy participants completed an emotional priming task and a nonemotional priming task. In the older adult group, reaction times in the emotional priming paradigm were not influenced by any of the prime conditions, whereas both groups exhibited similar facilitation effects induced by the congruent prime in the nonemotional task. The selective lack of an emotional priming effect in older adults shown in this preliminary report suggests that aging-induced changes in the ability to recognize emotions implicitly are directly dependent on emotional processing difficulties and not due to a general age-related modification of cognitive processes.     

Age-related changes in the misinformation effect

In these experiments, we examined the relation between age-related changes in retention and age-related changes in the misinformation effect. Children (5- and 6- and 11- and 12-year-olds) and adults viewed a video, and their memory was assessed immediately, 1 day, or 6 weeks later (Experiment 1). There were large age-related differences in retention when participants were interviewed immediately and after 1 day, but after the 6-week delay, age-related differences in retention were minimal. In Experiment 2, 11- and 12-year-olds and adults were exposed to neutral, leading, and misleading postevent information 1 day or 6 weeks after they viewed the video. Exposure to misleading information increased the number of commission errors, particularly when participants were asked about peripheral aspects of the video. At both retention intervals, children were more likely than adults to incorporate the misleading postevent information into their subsequent verbal accounts. These findings indicate that age-related changes in the misinformation effect are not predicted by age-related changes in retention.     

Age-related changes in cardiovascular response as a function of a chronic stressor and social support.

The effects of aging, chronic stress, and social support on cardiovascular functioning were examined using a cross-sectional design. Thirty-six family caregivers of Alzheimer's disease victims and 34 control Ss performed 2 active coping tasks while continuous noninvasive measures of cardiovascular activity were monitored. Results revealed that caregivers high in social support displayed typical age-related decreases in heart-rate reactivity, whereas caregivers low in social support displayed age-related increases in heart-rate reactivity. Analyses further indicated that only Ss with low social support were characterized by age-related increases in systolic blood pressure. These results suggest that social support can moderate age-related changes in cardiovascular functioning, particularly in Ss exposed to a chronic stressor.     

Age-related changes and gender differences in time estimation

A study was carried out in which age and gender differences were studied in the performance of an empty interval production task. The duration of these intervals was 10 s, 1 and 5 min. The sample was made up of 140 subjects, half male and half female, in seven different age groups from 8 to 70 years old. The age range permitted us to identify when differences begin to be significant. The results show an age-related increase in the underproduction of the intervals. The differences between age groups attained significance from 51 to 60 years onward. With regard to gender, the main result was a greater underproduction of longer intervals (1 and 5 min) for women. These findings were interpreted in terms of different models of time estimation.     

Age-related changes in aphasia type and stroke location

Two-hundred consecutive CT scans of patients with an infarction in the territory of the middle cerebral artery (MCA) were examined for evaluation of a possible relationship between age and stroke location. Two distinct procedures, one evaluating the incidence of four areas within the MCA territory and the other measuring some quantified parameters, were used. Statistical studies failed to show any significant correlation between these parameters and the age of patients. These results lead to refute previous claims that semiological changes in aphasia type with age in stroke patients may be due to a posterior shift of cerebral infarcts with age.     

Age-related decrease in recognition of emotional facial and prosodic expressions

The recognition of nonverbal emotional signals and the integration of multimodal emotional information are essential for successful social communication among humans of any age. Whereas prior studies of age dependency in the recognition of emotion often focused on either the prosodic or the facial aspect of nonverbal signals, our purpose was to create a more naturalistic setting by presenting dynamic stimuli under three experimental conditions: auditory, visual, and audiovisual. Eighty-four healthy participants (women = 44, men = 40; age range 20-70 years) were tested for their abilities to recognize emotions either mono- or bimodally on the basis of emotional (happy, alluring, angry, disgusted) and neutral nonverbal stimuli from voice and face. Additionally, we assessed visual and auditory acuity, working memory, verbal intelligence, and emotional intelligence to explore potential explanatory effects of these population parameters on the relationship between age and emotion recognition. Applying unbiased hit rates as performance measure, we analyzed data with linear regression analyses, t tests, and with mediation analyses. We found a linear, age-related decrease in emotion recognition independent of stimulus modality and emotional category. In contrast, the improvement in recognition rates associated with audiovisual integration of bimodal stimuli seems to be maintained over the life span. The reduction in emotion recognition ability at an older age could not be sufficiently explained by age-related decreases in hearing, vision, working memory, and verbal intelligence. These findings suggest alterations in social perception at a level of complexity beyond basic perceptional and cognitive abilities.     

Age,criterion flexibility,and item recognition

We examined young and older adults' ability to flexibly adapt response criterion on a recognition test when the probability that a test item had been studied was cued by test color. One word color signaled that the probability of the test item being old was 70% and a second color signaled that the probability of the test item being new was 70%. Young and older adults demonstrated similar levels of criterion shifting in response to color cues. Moreover, although both young and older adults were slowed when test-item color incorrectly predicted test-item status, the extent of slowing did not differ across age group. Putative measures of cognitive control predicted recognition accuracy but not the degree to which criterion changed with test-item color. These results suggest that adaptive criterion shifting does not tax cognitive control or, if it does require effort, may be no more onerous for older than for young adults.