Unsaid thoughts: Thinking in the absence of verbal logical connectives.

Combining two thoughts into a compound mental representation is a central feature of our verbal and non-verbal logical abilities. We here approach this issue by focusing on the contingency that while natural languages have typically lexicalised only two of the possible 16 binary connectives from formal logic to express compound thoughts-namely, the coordinators and -some of the remainder appear to be entertainable in a non-verbal, conceptual representational system-a -and this suggests a theoretical split between the "lexicalisation" of the connectives and the "learnability" of invented words corresponding to unlexicalised connectives. In a experiment aimed at tracking comprehension-related as well as reasoning-related aspects of the capacity to represent compound thoughts, we found that participants are capable of learning and interpreting a made-up word standing for logic's NAND operator, a result that indicates that unlexicalised logical connectives are not only conceptually available, but can also be mapped onto new function words, as in the case of coordinators, or connectives, a class of words that do not usually admit new coinages.

Parsing for Position.

Monitoring tasks have long been employed in psycholinguistics, and the end-of-clause effect is possibly the better-known result of using this technique in the study of parsing. Recent results with the tone-monitoring task suggest that tone position modulates cognitive load, as reflected in reaction times (RTs): the earlier the tone appears in a sentence, the longer the RTs. In this study, we show that verb position is also an important factor.

Disentangling perceptual and psycholinguistic factors in syntactic processing: Tone monitoring via ERPs.

Franco, Gaillard, Cleeremans, and Destrebecqz (Behavior Research Methods, 47, 1393-1403, 2015), in a study on statistical learning employing the click-detection paradigm, conclude that more needs to be known about how this paradigm interacts with statistical learning and speech perception. Past results with this monitoring technique have pointed to an end-of-clause effect in parsing-a structural effect-but we here show that the issues are a bit more nuanced. Firstly, we report two Experiments (1a and 1b), which show that reaction times (RTs) are affected by two factors: (a) processing load, resulting in a tendency for RTs to decrease across a sentence, and (b) a perceptual effect which adds to this tendency and moreover helps neutralize differences between sentences with slightly different structures.

Probing recursion.

The experimental probing of recursion in human performance is faced with non-trivial problems. Here, I analyse three case studies from the literature and argue that they tell us little about the underlying mental processes at play within each of these domains: (a) the question of whether experimental participants employ recursive rules in parsing artificial strings of nonsense syllables; (b) the role of self-embedded structures in reasoning and general cognition; and (c) the reputed connection between structural features of a given object and the corresponding, recursive rules needed to represent/generate it. I then outline what a recursive process would actually look like and how one could go about probing its presence in human behaviour, concluding, however, that recursive processes in performance are very unlikely, at least as far as fast, mandatory, and automatic modular processes are concerned.