Speech segmentation is facilitated by visual cues

Evidence from infant studies indicates that language learning can be facilitated by multimodal cues. We extended this observation to adult language learning by studying the effects of simultaneous visual cues (nonassociated object images) on speech segmentation performance. Our results indicate that segmentation of new words from a continuous speech stream is facilitated by simultaneous visual input that it is presented at or near syllables that exhibit the low transitional probability indicative of word boundaries. This indicates that temporal audio-visual contiguity helps in directing attention to word boundaries at the earliest stages of language learning. Off-boundary or arrhythmic picture sequences did not affect segmentation performance, suggesting that the language learning system can effectively disregard noninformative visual information. Detection of temporal contiguity between multimodal stimuli may be useful in both infants and second-language learners not only for facilitating speech segmentation, but also for detecting word–object relationships in natural environments.     

The momentum of human behavior in a natural setting

Adults with mental retardation in a group home received popcorn or coffee reinforcers for sorting plastic dinnerware. In Part 1 of the experiment, reinforcers were dispensed according to a variable-interval 60-s schedule for sorting dinnerware of one color and according to a variable-interval 240-s schedule for sorting dinnerware of a different color in successive components of a multiple schedule. Sorting rates were similar in baseline, but when a video program was shown concurrently, sorting of dinnerware was more resistant to distraction when correlated with a higher rate of reinforcement. In Part 2 of the experiment, popcorn or coffee reinforcers were contingent upon sorting both colors of dinnerware according to variable-interval 60-s schedules, but additional reinforcers were given independently of sorting according to a variable-time 30-s schedule during one dinnerware-color component. Baseline sorting rate was lower but resistance to distraction by the video program was greater in the component with additional variable-time reinforcers. These results demonstrate that resistance to distraction depends on the rate of reinforcers obtained in the presence of component stimuli but is independent of baseline response rates and response–reinforcer contingencies. Moreover, these results are similar to those obtained in laboratory studies with pigeons, demonstrating that the determination of resistance to change by stimulus–reinforcer relations is not confined to controlled laboratory settings or unique to the pigeon.     

Dependency, temporal contiguity, and response-independent reinforcement

A comparison was made of the effects of variable-interval, variable-time, and tandem variable-interval fixed-time schedules on key-peck responding of pigeons. The variable-interval component of the tandem schedule retained the response-reinforcement dependency; the fixed-time component allowed the temporal proximity between responding and reinforcement to vary, constrained only by the duration of the fixed-time interval. Response rates were highest during the variable-interval and lowest during the variable-time schedule. Intermediate response rates occurred during the tandem schedule. The results of a yoked control condition showed that the effects of the tandem schedule were not due simply to changes in reinforcement distribution or frequency. The results suggest that substantial reductions in responding occur when reinforcement is response-dependent but not necessarily contiguous with the response required to produce reinforcement.     

The S-R issue: its status in behavior analysis and in Donahoe and Palmer''s learning and complex behavior.

The central focus of this essay is whether the effect of reinforcement is best viewed as the strengthenng of responding or the strengthening of the environmental control of responding. We make the argument that adherence to Skinner's goal of achieving a moment-to-moment analysis of behavior compels acceptance of the latter view. Moreover, a thoroughgoing commitment to a moment-to-moment analysis undermines the fundamental distinction between the conditioning process instantiated by operant and respondent contingencies while buttressing the crucially important differences in their cumulative outcomes. Computer simulations informed by experimental analyses of behavior and neuroscience are used to illustrate these points.     

Allocation of speech in conversation

In a replication and extension of Conger and Killeen's (1974) widely cited demonstration of matching in conversations, we evaluated nine participants’ allocation of speech and gaze to two conversational partners. German speakers participated in two 90‐min sessions in which confederates uttered approval on independent variable‐interval schedules. In one of the sessions, confederates uttered approval contingent upon and contiguous with eye contact whereas in the other session approval was uttered independent of the participant's gaze. Several measures of participants’ verbal behavior were taken, including relative duration and rate of speech and gaze. These were compared to confederates’ relative rate of approval and relative duration and rate of talk. The generalized matching equation was fitted to the various relations between participants’ behavior and confederates’ behavior. Conger and Killeen's results were not replicated; participants’ response allocation did not show a systematic relation to the confederates’ relative rate of approval. The strongest relations were to overall talk, rather than approval. In both conditions, the participant talked more to the confederate who talked less—inverse or antimatching. Participants’ gaze showed the same inverse relation to the confederates’ talk. Requiring gaze to be directed toward a confederate for delivery of approval made no difference in the results. The absence of a difference combined with prior research suggests that matching or antimatching in conversations is more likely due to induction than to reinforcement.     

The reductive effects of noncontingent reinforcement fixed-time versus variable-time schedules.

The effects of fixed‐time (FT) and variable‐time (VT) schedules on responding were evaluated with 2 adults with mental retardation. Multielement and reversal designs were used to compare the effects of FT and VT schedules in reducing responses previously maintained on variable‐ratio reinforcement schedules. The schedules were equally effective in reducing the target behavior.     

Response-reinforcer relations and the maintenance of behavior

The effects on pigeons' key pecking of unsignaled delays of reinforcement and response-independent reinforcement were compared after either variable-interval or differential-reinforcement-of-low-rate baseline schedules. One 30-min session arranging delayed reinforcement and one 30-min session arranging response-independent reinforcement were conducted daily, 6 hr apart. A within-subject yoked-control procedure equated reinforcer frequency and distribution across the two sessions. Response rates usually were reduced more by response-independent than by delayed but response-contingent delivery of reinforcers. Under both schedules, response rates were lower when obtained delays were greater. These results bear upon methodological and conceptual issues regarding comparisons of contingencies that change the temporal response–reinforcer relations.     

Separating response dependency and response-reinforcer contiguity within a recycling conjunctive schedule

A procedure is described which disrupts response-reinforcer contiguity and response dependency and which demonstrates how the location of the response dependency in interval schedules can be regarded as a controlling variable in its own right. Rats' lever pressing produced sucrose on a recycling conjunctive fixed-time 30-second fixed-ratio 1 schedule of reinforcement. Reinforcement occurred only at the end of the fixed-time component on this schedule and only if a response had occurred during that component. This produced a pause-respond-pause pattern during the interreinforcer interval for all animals. When the location of the response dependency was then restricted to a 10-second period in the middle of the fixed-time component, the pattern was accentuated and response rates increased for all animals, while postreinforcement pauses decreased sharply for two animals. When responding was required in the first 10 seconds of the fixed-time component, responding peaked earlier in the interval for all animals. Response rates were slightly below those in the previous conditions, while postreinforcement pauses were between 2 and 6 seconds across animals.     

Conditioning of within-trial patterns of key pecking in pigeons

The possibility of conditioning systematic patterns of responding during brief discrete trials was studied by requiring hungry pigeons to key peck and then pause or to pause and then key peck in order to gain access to food. These schedules were highly effective in promoting decelerated and accelerated rates of responding, respectively, within individual trials; indeed, performance was quite similar to that observed when explicit external stimuli were correlated with “peck” and “pause” portions of the daily trials. Finally, schedules of reinforcement that did not selectively reinforce peck-pause or pause-peck patterns neither generated these patterns nor maintained them at the previous high levels. The results, therefore, confirm Shimp's (1976) proposal that organized groupings of discrete responses may function as operants—even in the absence of strict response-reinforcer contiguity.     

Conditioning of two-response patterns of key pecking in pigeons

On discrete trials, two response keys were made available to hungry pigeons and food reinforcement depended on the order in which the required two key pecks occurred. In different phases, only one of the four possible two-peck sequences (left-left, left-right, right-left, and right-right) produced food reinforcement. In each case, the pigeons learned to perform the correct two-peck sequence more often than the incorrect sequences. Furthermore, the course of differentiation mastery indicated that both reinforcement history and response-reinforcer contiguity influenced performance. These results reveal that response patterns comprising two instances of the same response left-left and right-right) or instances of two different responses (left-right and right-left) may function as operants, thereby extending the generality of conditioning principles from discrete responses to structured sequences of behavior. These and other results are discussed in terms of contiguity-based and memory-based models of learning.