Structural complexity as a determinant of serial pattern learning

A new methodology extends the study of serial pattern learning to nonhuman organisms by constructing patterns using elements that are both familiar and motivationally meaningful to animals. Two experiments examine the ability of rats to anticipate various quantities of food as measured by running times in a runway when the quantities occur in a serial order. In Experiment 1, a serial monotonic pattern (14-7-3-1-0 food pellets) produced more rapid learning and more accurate anticipation of the various quantities (“tracking”) than a serial nonmonotonic pattern (14-1-3-7-0 food pellets), particularly with respect to the final 0-pellet element. In Experiment 2, the same monotonic pattern generated faster learning and more accurate anticipation of pattern elements than a weakly monotonic pattern (14-5-5-1-0 pellets). Associative explanations including simple excitatory or inhibitory effects, temporal anticipation, reinforcement contrast, and the number and discriminability of pairwise associations are not adequate to account for the data. Rather, the formally defined structural complexity of each pattern adequately predicts its relative difficulty.     

Observer states and traits and the imitative process: A test of a new formulation

In three studies the formulation was tested that characteristics of the observer have an effect on imitation only in situations which provide little information concerning appropriate or expected behaviors. In Experiment I, female college students of high, medium, and low need for social approval underwent either a high or low arousal manipulation. Subjects observed a videotaped model who engaged in a size judgment task. For half the subjects the model received verbal reward (high information); for the other half the model received no feedback (low information). Subsequently, the model and subject responded alternately in the task during which no feedback was given. Neither need for social approval nor manipulated arousal was found to be systematically related to imitation in either information condition. However, the hypothesized relationships were found when subjects' arousal or anxiety levels were determined by self ratings. These results were replicated in a second, similar experiment. In a third experiment, which involved an improved arousal manipulation, the hypothesized relationships were confirmed.     

Reflection-impulsivity in normal and behavior-disordered children

The primary index of reflection- impulsivity is Kagan's Matching Familiar Figures Test (MFF), which yields both a latency and an error score. To evaluate further the construct validity of these measures, both the latency and error scores of 9- and 15-year-old normal and acting-out behavior-disordered children were compared. Young behavior-disordered children were found to be more impulsive than the other groups on the MFF error measure. No differences occurred on the MFF latency measure. This result is consistent with previous findings with normal children in supporting the construct validity of the MFF error score and raising questions about the construct validity of the MFF latency score. Findings were inconsistent with Kagan's assertion that normal children become more reflective with age. The older behavior-disordered children were more reflective on the error measure than the younger behavior-disordered children and had equivalent error scores to both age groups of normals. This finding suggested a lag in the development of reflection in behavior-disordered children.The authors wish to thank Dr. Kenneth C. Molkner for his valuable assistance in obtaining subjects and for his kind support.     

A biphasic 60-Hz synchronizer circuit for the recording of visually evoked responses in high-noise environments

A simple synchronizer clock circuit is described that aids in the rejection of 60-Hz noise from evoked potential measurements.     

Vowel recognition: Inferences from studies of forward and backward masking

The recognition of brief vowels was studied in forward and backward masking tasks. In a series of experiments in which both target and mask parameters were systematically varied, two populations of subjects were identified. The majority (Nonmaskers) evidenced little masking at any interstimulus interval, while relatively fewer subjects (Maskers) evidenced backward masking (but not forward masking) over a 100-200 ms interval. Increasing target set size systematically increased masking for the Maskers but not for the Nonmaskers. Adding white noise to the targets increased the extent of masking for both groups. These results suggest (1) that masking does not impose a substantive constraint on vowel perception in running speech, and (2) that multiple strategies may exist for vowel recognition.     

Performing item- and subject-based analyses using ALICE

By using the program ALICE, we are able to perform subject- and item-based analyses of randomly ordered sets of data without the usual computational effort. The program allows us to transform data and combine, partition, or systematically manipulate them by simple, readily interpretable instructions. Of equal importance to us is the ease with which students and staff learn to use the program independently.