Purpose
This paper aims to extend the companion paper on “infant psychophysics”, which concentrated on the role of in-lab observers (watchers). Infants cannot report their own perceptions, so for five decades their detection thresholds for sensory stimuli were inferred from their stimulus-evoked behavior, judged by watchers. The inferred thresholds were revealed to inevitably be those of the watcher–infant duo, and, more broadly, the entire Laboratory. Such thresholds are unlikely to represent the finest stimuli that the infant can detect. What, then, do they represent?
Design/methodology/approach
Infants’ inferred stimulus-detection thresholds are hypothesized to be attentional thresholds, representing more-salient stimuli that overcome distraction.
Findings
Empirical psychometric functions, which show “detection” performance versus stimulus intensity, have shallower slopes for infants than for adults. This (and other evidence) substantiates the attentional hypothesis.
Research limitations/implications
An observer can only infer the mechanisms underlying an infant’s perceptions, not know them; infants’ minds are “Black Boxes”. Nonetheless, infants’ physiological responses have been used for decades to infer stimulus-detection thresholds. But those inferences ultimately depend upon observer-chosen statistical criteria of normality. Again, stimulus-detection thresholds are probably overestimated.
Practical implications
Owing to exaggerated stimulus-detection thresholds, infants may be misdiagnosed as “hearing impaired”, then needlessly fitted with electronic implants.
Originality/value
Infants’ stimulus-detection thresholds are re-interpreted as attentional thresholds. Also, a cybernetics concept, the “Black Box”, is extended to infants, reinforcing the conclusions of the companion paper that the infant-as-research-subject cannot be conceptually separated from the attending laboratory staff. Indeed, infant and staff altogether constitute a new, reflexive whole, one that has proven too resilient for anybody’s good.
