Selective exposure and dissonance after decisions

Well-known literature reviews from the 1960s question whether cognitive dissonance underlies experimental participants' selective exposure of themselves to consonant messages and avoidance of dissonant ones. A meta-analytic review of 16 studies published from 1956 to 1996 and involving 1,922 total participants shows that experimental tests consistently support the supposition that dissonance is associated with selective exposure (r = .22, p < .001). Statistical power exceeded .99. Advances in statistical methodology and increased attention to selecting appropriate tests of dissonance theory were essential to finally resolving this question.     

Sea lions and equivalence: expanding classes by exclusion

Experiments have shown that human and nonhuman subjects are capable of performing new arbitrary stimulus-stimulus relations without error. When subjects that are experienced with matching-to-sample procedures are presented with a novel sample, a novel comparison, and a familiar comparison, most respond by correctly selecting the novel comparison in the presence of the new sample. This exclusion paradigm was expanded with two California sea lions that had previously formed two 10-member equivalence classes in a matching-to-sample procedure. Rather than being presented with a novel sample on a given trial, the sea lions were presented with a randomly selected familiar member of one class as the sample. One of the comparisons was a randomly selected familiar member of the alternative class, and the other was a novel stimulus. When required to choose which comparison matched the sample, the subjects reliably rejected the familiar comparison, and instead selected the unfamiliar one. Next, the sea lions were presented with transfer problems that could not be solved by exclusion; they immediately grouped the new stimuli into the appropriate classes. These findings show that exclusion procedures can rapidly generate new stimulus relations that can be used to expand stimulus classes.     

Perception and production of rise-fall intonation in American English

At the segmental level, the rate of speaking affects the degree of physical undershoot of articulatory targets and the resulting perception. Little is known regarding evidence of these effects at the suprasegmental level, particularly in intonation. In this study, the effect of rate of speaking on fundamental frequency and on perceptual judgments of peak pitch in a rise-fall intonation pattern was investigated. First, speakers produced rise-fall intonations in sentence contexts at slow, normal, and fast speaking rates. Peak fundamental frequencies (F0) of the slow productions were significantly lower than those of the normal or fast productions. The mean normal rate production of the word Miami was used as a model for the target word in a series of subsequent perceptual experiments. Altering the duration of the target word to represent slow, normal, and fast rates of speaking did not affect listener judgment of peak pitch. Finally, the pitch of the target word was measured in a sentence context. No differences between peak pitch in isolation or in sentence context were found. It was concluded that the production and perception of this form of intonation was not subject to the effects of rate that are seen at the segmental level.     

Specificity of the MMPI-2 Fake Bad Scale as a marker for personal injury malingering

Psychologists who evaluate patients in medicolegal contexts should utilize objective assessment data with empirically established sensitivity and specificity for identifying negative response bias. The purpose of this study was to investigate the specificity of the Fake Bad Scale for identifying negative response bias in personal injury claimants. The cutoff scores proposed by Lees-Haley and colleagues were applied a federal prison, medical outpatients, and patients from to inmate volunteers from substance abuse unit. Half of the inmates were given instructions to malinger psychopathology to affect the adjudication process, and the remaining inmates and all of the hospital patients were given standard instructions. The original cutoff scores correctly identified the majority of inmates instructed to malinger psychopathology, but these scores resulted in unacceptably high rates of false positive classifications. The revised cutoff scores resulted in fewer false positives, i.e., 8%-24%.     

Discrimination of individual vocalizations by black-capped chickadees (Poecile atricapilla)

The auditory perceptual abilities of male black-capped chickadees (Poecile atricapilla) were examined using an operant go/no-go discrimination among 16 individual vocalizations recorded at 5 m. The birds learned to discriminate about equally well among eight male chickadee fee-bee songs and eight female zebra finch (Taeniopygia guttata) distance calls. These results do not indicate that chickadees have a species-specific advantage in individual recognition for conspecific over heterospecific vocalizations. We then transferred the chickadees to a discrimination of the same songs and calls rerecorded at a moderate distance. These results showed accurate transfer of discrimination from 16 vocalizations recorded at 5 m to novel versions of the same 16 songs and calls rerecorded at 25 m. That is, chickadees recognized individual songs and calls despite degradation produced by rerecording at 25 m. Identifying individual vocalizations despite their transformation by distance cues is here described as a biologically important example of perceptual constancy.     

Stem homographs and lemma level representations

Previous studies have found that priming a target like cerr-o ("hill") with an unmasked stem-homograph (e.g., cerr-ar, "to close") or with an unmasked allomorph of a stem-homograph (e.g., cierr-a, "he/she/it closes") has an inhibitory effect on target recognition. We report evidence from stem-homograph priming studies that implicate both morphological parsing and lexical selection processes at the lemma level. We argue that stem-homograph inhibition is the product of lexical selection mechanisms that are engaged just when a fully ambiguous stimulus (here, an inflectional stem) must be assigned one of its viable interpretations in order to afford conscious perception of lexical identity.     

The length of the retention interval,forgetting, and subjective similarity

A long retention interval tends to result in the poor retention known as forgetting. A high subjective similarity between stimuli frequently produces their poor retention. Thus, a long retention interval may increase the subjective similarity between stimuli (the RIISS hypothesis), and this increase may produce forgetting. To examine this hypothesis, college students made speeded same-different discriminations between two lines or tones of different lengths or frequencies that were 400 ms or 3,300 ms apart, and they rated the similarity of these stimuli. The long interval produced poorer overall performance as expected, but also produced poorer performance on different than same stimuli, implying that it increased the subjective similarity between the initial and subsequent stimuli, and it also increased rated similarity, in support of the RIISS hypothesis. The position that stored stimuli lose less common information than distinctive information explains RIISS evidence better than does perturbation theory.     

Age differences in overlapping-task performance: evidence for efficient parallel processing in older adults

Two psychological refractory period (PRP) experiments were conducted to examine overlapping processing in younger and older adults. A shape discrimination task (triangle or rectangle) for Task 1 (T1) and a lexical-decision task (word or nonword) for Task 2 (T2) were used. PRP effects, response time for T2 increasing as stimulus onset synchrony (SOA) decreased, were obtained for both age groups. The effect of word frequency on T2 was smaller at the short SOA than at the long SOA, reflecting slack effects, which were larger for older than younger adults in both experiments. These results suggest that older adults can perform lexical access of T2 in parallel with the processing of T1 at least as efficiently as younger adults.