Retrieving effectively from source memory: Evidence for differentiation and local matching processes

The ability to distinguish between different explanations of human memory abilities continues to be the subject of many ongoing theoretical debates. These debates attempt to account for a growing corpus of empirical phenomena in item-memory judgments, which include the list strength effect, the strength-based mirror effect, and output interference. One of the main theoretical contenders is the Retrieving Effectively from Memory (REM) model. We show that REM, in its current form, has difficulties in accounting for source-memory judgments - a situation that calls for its revision. We propose an extended REM model that assumes a local-matching process for source judgments alongside source differentiation. We report a first evaluation of this model's predictions using three experiments in which we manipulated the relative source-memory strength of different lists of items. Analogous to item-memory judgments, we observed a null list strength effect and a strength-based mirror effect in the case of source memory. In a second evaluation, which relied on a novel experiment alongside two previously published datasets, we evaluated the model's predictions regarding the manifestation of output interference in item and lack of it in source memory judgments. Our results showed output interference severely affecting the accuracy of item-memory judgments but having a null or negligible impact when it comes to source-memory judgments. Altogether, these results support REM's core notion of differentiation (for both item and source information) as well as the concept of local matching proposed by the present extension.

Acute monoarthritis in children: clinical and laboratory factors distinguishing septic arthritis from noninfectious inflammatory arthritis

OBJECTIVE

Distinguishing septic arthritis from specific inflammatory arthritis in children with acute monoarthritis can be a clinical challenge. This study aimed to assess the diagnostic performance of presenting clinical and laboratory findings for distinguishing septic arthritis from common forms of noninfectious inflammatory arthritis in children with acute monoarthritis.

PATIENTS AND METHODS

Children presented for the first episode of monoarthritis were retrospectively reviewed and then divided into two groups: (1) the septic group, 57 children with true septic arthritis, and (2) the non-septic group, 60 children with several types of noninfectious inflammatory arthritis. Several clinical findings and serum inflammatory markers on admission were documented.

RESULTS

Univariate analyses demonstrated that body temperature, weight-bearing status, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), white blood cell count (WCC), absolute neutrophil count (ANC), and neutrophil percentage (NP) levels were significantly higher in the septic group than in the non-septic group (p<0.001 for each variable). Based on the ROC analysis, optimum diagnostic cut-off values were 63 mg/L for CRP, 6,300/mm3 for ANC, 53 mm/h for ESR, 65% for NP, 37.1°C for body temperature, and 12,100/mm3 for WCC. While children with no presenting factor had a 4.3% risk of having septic arthritis, those with six predictors had a risk of 96.2%.

CONCLUSIONS

A CRP level of ≥63 mg/L is the best independent predictor of septic arthritis among the commonly used serum inflammatory markers (ESR, WCC, ANP, NP). It should be borne in mind that a child with zero predictors may still have a 4.3% risk of septic arthritis. Thus, clinical assessment is still imperative in managing children presenting with acute mono-arthritis.

Turkish Emotional Word Norms for Arousal, Valence, and Discrete Emotion Categories

The present study combined dimensional and categorical approaches to emotion to develop normative ratings for a large set of Turkish words on two major dimensions of emotion: arousal and valence, as well as on five basic emotion categories of happiness, sadness, anger, fear, and disgust. A set of 2031 Turkish words obtained by translating Affective Norms for English Words to Turkish and pooling from the Turkish Word Norms were rated by a large sample of 1527 participants. This is the first comprehensive and standardized word set in Turkish offering discrete emotional ratings in addition to dimensional ratings along with concreteness judgments. Consistent with Affective Norms for English Words and word databases in several other languages, arousal increased as valence became more positive or more negative. As expected, negative emotions (anger, sadness, fear, and disgust) were positively correlated with each other, whereas the positive emotion, happiness, was negatively correlated with the negative emotion categories. Data further showed that the valence dimension was strongly correlated with happiness, and the arousal dimension was mostly correlated with fear. These findings show highly similar and consistent patterns with word sets provided in other languages in terms of the relationships between arousal and valence dimensions, relationships between dimensions and specific emotion categories, relationships among specific emotions, and further support the stability of the relationship between basic discrete emotions at the word level across different cultures.

Release from output interference in recognition memory: A test of the attention hypothesis

Retrieval results in both costs and benefits to episodic memory. Output interference (OI) refers to the finding that episodic memory accuracy decreases with increasing test trials. Release from OI is the restoration of original accuracy at some point during the test. For example, a release from OI in recognition memory testing occurs when the semantic similarity between stimuli decreases midway through testing, suggesting that item representations stored on early trials cause interference on tests occurring on later trials to the extent that the earlier items share features with the latter items. In two recognition memory experiments, we demonstrate release from OI for words and faces. We also test whether release from OI is the result of interference or is due to a boost in attention caused by reorienting to a novel stimulus type. A test for the foils presented during the initial test list supports the interference account of OI. Implications for models of memory are discussed.

Molecular investigation of Coxiella burnetii infections in aborted sheep in eastern Turkey

Q fever is a zoonotic disease that occurs worldwide and is caused by the obligate intracellular bacterium Coxiella burnetii. The aim of this study was to investigate the presence of C. burnetii infection in aborted sheep in eastern Turkey using PCR. A total of 200 fetuses were collected from aborted sheep belonging to 200 herds in different locations in the eastern part of Turkey. Foetal organ samples such as liver, spleen, lung and stomach were taken and the DNA was purified from two hundred pooled samples. PCR analysis of C. burnetii presence in infected organs was performed, and 4 samples (2%) were found positive. In addition, the pooled organ suspensions were inoculated to embryonated chicken eggs, and PCR analysis of yolk sacs showed C. burnetii DNA in 5 samples (2.5%). This study shows that C. burnetii infection has an important role in sheep abortions in eastern Anatolia region.

Age and response bias: Evidence from the strength-based mirror effect

Performance in episodic memory is determined both by accurate retrieval from memory and by decision processes. A substantial body of literature suggests slightly poorer episodic memory accuracy for older than younger adults; however, age-related changes in the decision mechanisms in memory have received much less attention. Response bias, the willingness to endorse an item as remembered, is an important decision factor that contributes to episodic memory performance, and therefore understanding age-related changes in response bias is critical to theoretical development. We manipulate list strength in order to investigate two aspects of response bias. First, we evaluate whether criterion placement in episodic memory differs for older and younger adults. Second, we ask whether older adults have the same degree of flexibility to adjust the criterion in response to task demands as younger adults. Participants were tested on weakly and strongly encoded lists where word frequency (Experiment 1) or similarity between targets and foils (Experiment 2) was manipulated. Both older and younger adults had higher hit rates and lower false-alarm rates for strong lists than for weak lists (i.e., a strength-based mirror effect). Older adults were more conservative (less likely to endorse an item as studied) than younger adults, and we found no evidence that older and younger adults differ in their ability to flexibly adjust their criterion based on the demands of the task.

Effects of spacing of item repetitions in continuous recognition memory: does item retrieval difficulty promote item retention in older adults?

BACKGROUND/STUDY CONTEXT: Older adults exhibit an age-related deficit in item memory as a function of the length of the retention interval, but older adults and young adults usually show roughly equivalent benefits due to the spacing of item repetitions in continuous memory tasks. The current experiment investigates the seemingly paradoxical effects of retention interval and spacing in young and older adults using a continuous recognition memory procedure.

METHODS

Fifty young adults and 52 older adults gave memory confidence ratings to words that were presented once (P1), twice (P2), or three times (P3), and the effects of the lag length and retention interval were assessed at P2 and at P3, respectively.

RESULTS

Response times at P2 were disproportionately longer for older adults than for younger adults as a function of the number of items occurring between P1 and P2, suggestive of age-related loss in item memory. Ratings of confidence in memory responses revealed that older adults remembered fewer items at P2 with a high degree of certainty. Confidence ratings given at P3 suggested that young and older adults derived equivalent benefits from the spacing between P1 and P2.

CONCLUSION

Findings of this study support theoretical accounts that suggest that recursive reminding and/or item retrieval difficulty promote item retention in older adults.