Why do wages become more rigid during a recession than during a boom?

Table 6 Layoff regression (probit)

Dependent variable: layoff ==1	(1)	(2)	(3)	(4)
Proxy of p:	p = CPI		p = Output
p/100	-0.1265	-0.1182	-0.0268	-0.0230
	(0.0632)	(0.0669)	(0.0122)	(0.0098)
Non-union Worker	0.0016	0.0011	0.0021	0.0014
	(0.0009)	(0.0005)	(0.0012)	(0.0007)
Male	0.0004	0.0005	0.0005	0.0006
	(0.0005)	(0.0004)	(0.0007)	(0.0004)
High School	-0.0013	-0.0008	-0.0016	-0.0010
	(0.0005)	(0.0005)	(0.0008)	(0.0007)
Junior College	-0.0008	-0.0006	-0.0010	-0.0007
	(0.0002)	(0.0003)	(0.0004)	(0.0004)
University	-0.0012	-0.0008	-0.0017	-0.0010
	(0.0003)	(0.0004)	(0.0006)	(0.0006)
Experience	-0.0000	-0.0000	-0.0000	-0.0000
	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Experience ²/100	0.0000	0.0000	0.0001	0.0000
	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Tenure	-0.0000	-0.0000	-0.0000	-0.0000
	(0.0000)	(0.0000)	(0.0000)	(0.0000)
Tenure ²/100	-0.0000	-0.0000	-0.0000	-0.0000
	(0.0001)	(0.0001)	(0.0001)	(0.0001)
Married	-0.0007	-0.0012	-0.0008	-0.0013
	(0.0006)	(0.0015)	(0.0009)	(0.0016)
Number of Children	-0.0000	-0.0001	-0.0001	-0.0001
	(0.0001)	(0.0001)	(0.0002)	(0.0002)
ln(Firm Size)	-0.0002	-0.0001	-0.0003	-0.0002
	(0.0001)	(0.0001)	(0.0002)	(0.0001)
Regional Dummies	No	Yes	No	Yes
Industry Dummies	No	Yes	No	Yes
Occupation Dummies	Yes	Yes	Yes	Yes
R-squared	0.138	0.235	0.123	0.217
Observations	4342	3164	4342	3164

Note: Marginal effects evaluated at the sample mean are reported. Standard errors clustered at industry levels are in parentheses under the regression coefficients. All explanatory variables, except for the gross-output deflators, represent information reported at the beginning of year t. The reference group for the education dummy variables is “Junior High School.” CPI is the industry-level consumer price index during January of each year.