Novelty and familiarity as redundant cues in retardate discrimination learning.

Forty retarded children, a Low Mental Age (MA) Group (mean MA 3-3 yrs.) and a High MA Group (mean MA 5–7 yrs.) were trained on 120 different two-choice visual discrimination problems. For all subjects, half of these problems were standard four-trial problems (Standard Condition). The remaining 60 problems were variants of the Moss-Harlow Design, the first trial differing from the initial two-choice trial of the Standard Condition in having only a single stimulus present, either the positive stimulus (Positive Condition) or the negative stimulus (Negative Condition), in both cases followed by three trials with both stimuli present. Each subject received either Positive Condition Problems or Negative Condition Problems, but not both. An analysis of Trial 2 performance revealed that although no interproblem changes in the Standard Condition occurred, there were large initial performance differences and large interproblem changes in the Positive and Negative Conditions which varied with MA. Initial performance differences were interpreted as a differential preference for novel and familiar stimuli in the two MA Groups. Changes in interproblem performance were consistent with the hypothesis that these MA dependent novelty-familiarity preferences could be influenced by novelty-familiarity redundancy training. These interpretations were supported by predictions from theory.     

Infants' discrimination of faces by using biological motion cues

We report two experiments in which we used animated averaged faces to examine infants' ability to perceive and discriminate facial motion. The faces were generated by using the motion recorded from the faces of volunteers while they spoke. We tested infants aged 4-8 months to assess their ability to discriminate facial motion sequences (condition 1) and discriminate the faces of individuals (condition 2). Infants were habituated to one sequence with the motion of one actor speaking one phrase. Following habituation, infants were presented with the same sequence together with motion from a different actor (condition 1), or a new sequence from the same actor coupled with a new sequence from a new actor (condition 2). Infants demonstrated a significant preference for the novel actor in both experiments. These findings suggest that infants can not only discriminate complex and subtle biological motion cues but also detect invariants in such displays.     

Stimulus and temporal cues in classical conditioning

In 2 experiments, separate groups of rats were given stimulus conditioning, temporal conditioning, untreated control and (in Experiment 2) learned irrelevance control procedures, followed by a compound with both stimulus and temporal cues. Stimulus conditioning consisted of a random 15-s duration conditioned stimulus (CS) followed by food; temporal conditioning consisted of food-food intervals of fixed 90 s (Experiment 1) or fixed 75 + random 15 s (Experiment 2). The stimulus group abruptly increased responding after CS onset, and the temporal group gradually increased responding over the food-food interval. When the food-food interval was fixed 90 s, the temporal cue exerted stronger control in the compound, whereas when the food-food interval was fixed 75 + random 15 s, the stimulus cue exerted stronger control. The strength of conditioning, temporal gradients of responding, and cue competition effects appear to reflect simultaneous timing of multiple intervals.     

On energy-dependent cues in duration discrimination

We consider the possibility that, in a duration discrimination task involving very short empty time intervals, T and T + ?T, bounded by brief auditory pulses, there may be a critical value of the base duration T within the range 50–300 msec below which duration is coded on the basis of sensory interactions between the markers which bound the interval. With ?T fixed at 10 msec, the functional relation between performance and base duration was determined under three levels of marker intensity. Changing the intensity by 37 dB resulted in the same small change in performance at the shortest base duration (50 msec), where it is most likely that an intensity-dependent interaction could be present, as was obtained at the longest base duration (250 msec), where such an interaction should be minimally effective as a cue for duration discrimination. The code for the duration of an empty auditory interval greater than 50 msee probably is not dorived from energy-dependent processes.     

The effect of partially valid cues on children's discrimination learning

Second grade children were administered a two-choice discrimination learning task in which irrelevant dimensions were correlated .50, .75, or 1.00 with the 100 percent rewarded cue. The results indicated that when a cue was partially correlated with reward .75, learning was retarded. When all cues were relevant and redundant (r = 1.00), learning was most rapid. These results supported an implication of Hypothesis Testing Theory that partially correlated or partially valid cues would not be eliminated rapidly, thus retarding acquisition of the correct response.     

Use of position and feature cues in discrimination learning by the whiptail lizard (Cnemidophorus inornatus)

Animals use a variety of cue types to locate and discriminate objects. The ease with which particular cue types are learned varies across species and context. An enormous literature contains comparisons of spatial cue use to use of other cue types, but few experiments examine the ease with which various nonspatial cues are learned. In addition, few studies have examined cue use in reptiles. Thus, the authors compared whiptail lizards' (Cnemidophorus inornatus) ability to learn and reverse a discrimination using either position (left or right) or visual feature cues. Lizards learned and reversed the task using position cues faster and with greater accuracy than using feature cues.     

Using emotional cues in a discrimination learning task: Effects of trait emotional intelligence and affective state

Individuals may differ in their ability to learn the significance of emotional cues within a specific context. If so, trait emotional intelligence (EI) may be associated with faster cue learning. This study (N = 180) tested whether trait EI predicts faster learning of a critical cue for discriminating “terrorists” from “non-terrorists”, using virtual-reality heads as stimuli. The critical cue was either facial emotion (positive or negative), or a neutral feature (hat size). Cognitive ability and subjective state were also assessed. Participants were faster to learn with an emotive cue. Surprisingly, high trait EI was correlated with poorer performance, especially early in learning. Subjective distress was also associated with impaired learning to emotive cues.     

Negative anticipatory contrast and preference conditioning: flavor cues support preference conditioning, and environmental cues support contrast.

In 2 experiments, access to a 0.15% saccharin solution was followed on alternating days by access to a 32% sucrose solution and the same saccharin solution. In Experiment 1, rats increased both intake of and preference for a flavored saccharin solution that predicted sucrose, but neither effect was found using a predictive odor cue alone. Experiment 2 replicated the predictive flavor results but showed suppression of saccharin intake when environmental cues predicted sucrose. When both flavor and environment predicted sucrose, saccharin intake did not change, but preference for the predictive flavor increased. Discriminative taste cues appear to facilitate the development of preference conditioning, but environmental cues favor negative anticipatory contrast effects. Also, preference conditioning and contrast may develop concurrently and compete for expression.     

The basic laws of conditioning differ for elemental cues and cues trained in compound

The cue-duration effect (i.e., longer cues result in less conditioned responding than shorter cues) was examined as a function of whether cues were trained alone or in compound. Compound (AX) or elemental (X) cues of either long or short duration were paired with the unconditioned stimulus. In testing with X alone, the cue-duration effect was observed with elementally trained cues, but not with compound cues. Instead, stronger responding resulted from training with long compound cues relative to short compound cues (i.e., a reversed cue-duration effect). Moreover, an overshadowing effect (i.e., decreased responding due to compound conditioning) was observed when conditioning was conducted with a short cue, but compound conditioning resulted in enhanced responding when it was conducted with a long cue (i.e., reversed overshadowing). These findings are consistent with other recent demonstrations that some laws of learning that apply to elementally trained cues do not similarly apply to cues trained in compound.     

Relational and absolute cues in auditory discrimination by monkeys

Rhesus monkeys were trained to make auditory frequency, intensity, and duration discriminations. Initial training was carried out with a procedure which allowed the utilization of either relational cues or absolute cues. Later tests with similar auditory parameters allowed only the utilization of relational cues. Performance on these latter tests indicated that relational rather than absolute cues had been utilized when both types were available on the frequency and intensity discrimination tasks. However, absolute rather than relational cues were apparently utilized in making duration discriminations.